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Tyvek Under Roof Steel?

Tyvek Under Roof Steel?

Reader BRANDON in MIDDLEBOROUGH writes:

“Greetings I’m writing to discuss the best practice for what to place under a metal roof. I am building a post frame, for shop use and will eventually be insulted. I had initially intended to install a WRB, like Tyvek, under the sheet metal roof. My thought was that the inside of the shop will have a vapor barrier and insulation, thus the warm air would not come in contact with the steel and create condensation. Is this thinking flawed?”

WRBs allow moisture to pass through outward and not return inward. Even with a vapor barrier between your ceiling finish and floor of attic insulation, a properly vented attic does allow air to flow in through eave vents and out through ridge.

According to building scientist and founding principal of Building Science Corporation Joe Lstiburek, “Plastic vapor barriers should only be installed in vented attics in climates with more than 8,000 heating degree days.” For extended reading on heating degree days, please see: https://www.hansenpolebuildings.com/2022/11/what-is-degree-day/

You will want to make certain to have intakes and exhaust in proper proportion. Provision of 1 square foot of NFVA for each 300 square feet of attic floor if both following conditions are applicable:

• A Class 1 (≤ 0.1 Perm) or 2 (> 0.1 to ≤ 1.0 Perm) vapor retarder is installed on warm-in-winter side of ceiling when the structure is located in climate zone 6, 7, or 8.
• At least 40%, but not more than 50% of NFVA is provided by vents located not more than 3 feet below roof’s highest point.
• Provision for a minimum 1 inch air space between roof sheathing and insulation in attic at vent location. Air flowing into and out of your attic space may very well contain more moisture than desired, some of which could pass through your WRB and become trapped between WRB and roof steel.

My recommendation would be to order your roof steel with an Integral Condensation Control factory applied (read more here: https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/).

This entry was posted in Ventilation, Building Interior, Insulation, Pole Barn Questions, Workshop Buildings, Pole Barn Design, Roofing Materials, Pole Barn Heating, Pole Barn Planning, Barndominium and tagged Ventilation, tyvek, moisture barrier, integral condensation control, insulation, vapor barrier, steel roofing on October 15, 2024 by Rick Ochs.

Fasteners in ACQ, Vapor Barriers, and Buildings in NC

This Wednesday the Pole Barn Guru answers reader questions about use of which fasteners are best to use in to ACQ treated columns, the need for a vapor barrier in Washington State, and Hansen Buildings in North Carolina.

DEAR POLE BARN GURU: Potential new customer here. Doing a small job on my own right now.

What should I use for attaching 2x material into uc4b posts? Is stainless steel required? Nails or screws? I was told by Fasten Master that their ACQ approved screws are only approved for uc4a.

Thanks in advance. CHAD

DEAR CHAD: ACQ is highly problematic as, if water is added to the connection, a chemical reaction is created literally “eating” steel. This was found to be a huge issue with deck construction. Code requirement would be for HDG (hot dipped galvanized) fasteners into pressure preservative treated lumber. We would recommend Simpson SDWS screws (it is what we provide for all of our buildings).

DEAR POLE BARN GURU: Existing 4 year old pole building on property that we bought (building is heated living space ). Siding is T1-11 by prior owner. Here is the roof detail from top to bottom when we purchased it; metal roofing, MBI blanket, 2×6 purlins, purlin cavity filled with R-19 unfaced batt, 2×12 LVL rafters thru bolted to treated posts, sheetrock secured to bottom of purlins. First problem- not vented properly. Second problem- not enough insulation. We just changed the roof side ( per an engineer calcs ); removed the metal, removed the MBI blanket, added 2×4 sleepers flat 2′ on center running from eave to ridge, added 1/2 CDX, added asphalt shingles roofing, now there is venting over the top of the insulation from eave to ridge vent. Now to the inside space ( the building company said for a heated living space ) add 2×6 between the 2×12 LVL flush to the LVL bottom at 2′ OC then fill that void with a R30 batt, then install a new ceiling.1) Do you agree ?2) Do I need to remove the sheetrock, or can I cut a bunch of holes in it ?3) I plan to use TrussCore for the new ceiling finish, what do you suggest for a vapor barrier behind the TrussCore? I appreciate your thoughts in advance. PS. building is in western WA state. ALAN in STANWOOD

DEAR ALAN: Sounds like you bought into a real mess.

I don’t believe your proposed R-30 batts are going to come anywhere close to meeting Washington state’s energy code requirements: https://sbcc.wa.gov/sites/default/files/2024-01/2021_WSEC_R_2ndEd_012524.pdf

I would remove sheetrock, it is putting unnecessary weight upon your roof system and could result in deflection issues. If purlins overly deflect, your asphalt shingle roof will have obvious dips between rafters.

You should not need a vapor barrier between ceiling finish and framing.

DEAR POLE BARN GURU: Why is North Carolina not included in your list of locations to ship a pole barn house? RODNEY in MURPHY

DEAR RODNEY: Hansen Pole Buildings has provided over 100 fully engineered custom designed post frame buildings to our clients in the Carolinas, (as well as every state). To the best of our knowledge, there is no excluded list of any United States location we would not ship a pole barn home to (Hawaii and Alaska barndominiums are shipped to Port of Tacoma for our clients to arrange barge or container transport).

This entry was posted in Roofing Materials, Constructing a Pole Building, Barndominium, Pole Barn Planning, Pole Building Siding, Ventilation, Lumber, Building Interior, Insulation, Columns, Pole Barn Questions, Pole Barn Heating, Pole Barn Design and tagged Strong-Drive SDWS Timber Screws, North Carolina, insulation, vapor barrier, ACQ treated lumber on October 2, 2024 by Rick Ochs.

Footing Diameter, Non-Ground Contact Columns, and Ceiling Insulation

This Wednesday the Pole Barn Guru answers reader questions about the required footing diameter for a 20’x24′ pole barn garage, use of non-ground contact columns on a concrete stem wall or thickened edge, and Insulating a cathedral ceiling in a barndominium.

DEAR POLE BARN GURU: I am looking to build a 20ft x 24ft pole barn garage. The footings are going to be drilled and filled with concrete now, with the structure being completed at a future date. My city engineer requires 30″ deep footings. He was not able to say for sure what diameter footing I needed to drill. Do you have any insight to what diameter footing I should expect to need for this size structure? JOE in CINCINNATI

DEAR JOE: Ultimately required diameter will depend upon soil bearing capacity and imposed loads. If you are single story, chances are good an engineer would specify 18 inch diameter.

DEAR POLE BARN GURU: I was fortunate to have acquired enough columns for a building. My question as these are not ground contact columns and I prefer at this time to not pour a concrete floor is it allowable to pour a perimeter of concrete ( 2’x2′,3’x2′?) thickened edge if you will and set the columns to keep them off the ground? I was thinking partially setting rebar perpendicular in the concrete leaving 1-2′ protruding towards the buildings center to tie a future slab possibility into what would be the existing edge ( foundation). This is a cost driven situation as you may have already surmised. Really appreciate your knowledge and time. RICK in TWO RIVERS

DEAR RICK: To save further on costs, you can pour concrete piers to support engineered wet-set brackets. This would be much simpler than pouring a concrete perimeter. Bottom of piers should be at or below frost line. https://www.hansenpolebuildings.com/2019/05/sturdi-wall-plus-concrete-brackets/

DEAR POLE BARN GURU: Insulating a cathedral ceiling in a barndominium. It is house wrapped and single bubble beneath the metal roof panels. Girts and purlins are on 2 ft centers. Was planning on using Rockwool and Siga Majrex with the appropriate air gap. Building is vented through soffit on all sides. Also planning on using soffit baffles( and should I take them to the peak) , along with plastic vapor barrier above stone before concrete. Is there a better way, other than spray foam, and would that be in the ceiling over top of the single bubble also? Thanks. CHAD in DILLINER

DEAR CHAD: Thank you for the photos. You need to seal any venting coming in from endwalls. This can be done by placing 2×4 blocking flat between purlins on top of end truss. Install baffles between trusses and run them “uphill” to beyond depth of your insulation to be blown in. Do not use a vapor barrier between ceiling finish and truss bottom chords. Ideally blow in granulated Rockwool above ceiling (second choice would be fiberglass).

This entry was posted in Trusses, Barndominium, Ventilation, Concrete, Lumber, Building Interior, Insulation, Pole Barn Questions, Budget, Pole Barn Design, Professional Engineer, Constructing a Pole Building, Columns, Pole Barn Homes and tagged soil bearing capacity, wet set brackets, thickened slab, footing diameter, ground contact, ceiling insulation, dry columns, footings, insulation, vapor barrier on August 21, 2024 by Rick Ochs.

Insulate a Post Frame Building, Ventilation, and Column Sizes

This week the Pole Barn Guru answers reader questions about the most economical way to insulate a pole barn style building, advice on ventilation, and the best column size for a building in Michigan.

DEAR POLE BARN GURU: Hello, I am looking at either building a pole barn style or hybrid Steel column, post and joist with 2×6 purlins and girts. If I were to place 1/2″ sheathing on the walls and roof, install 30 felt paper then my metal on the walls and roof, what would be the most economical way to insulate it. It will be my hobby shop not a living space. ROBERT in OCEAN PARK

DEAR ROBERT: All of these recommendations are based upon meeting energy code requirements for conditioned buildings. Washington State will be a stickler for these.

1/2″ sheathing and felt is probably not your best design solution (besides being expensive).

Roof – order roof steel with a factory applied Integral Condensation Control https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/

Order trusses with raised heels (deep enough to not compress blown in attic fiberglass insulation) https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/

Order trusses designed to support weight of a ceiling and install one. Blow in R-60 fiberglass above ceiling. Vent eave and ridge in correct proportions https://www.hansenpolebuildings.com/2023/06/274512/

Walls: From out-to-in:

Steel siding; Weather Resistant Barrier (Housewrap); 2×8 bookshelf wall girts; R-30 unfaced Rockwool batts; 6mil clear plastic vapor barrier; Interior finish

Slab: If using radiant floor heat, R-10 under slab and at slab edge. Otherwise R-10 rigid boards down two feet, then out two feet.

DEAR POLE BARN GURU: I have an 18×20 metal building (my house) that’s covered with spray foam insulation at 1.5″ on the walls and 2″ on the inside roof. The entire space will be conditioned. I am now reading that I may need to ventilate the space. I thought the purpose of the spray foam was to make it air-tight as a closed envelope system. So, can you explain what I need to know about venting? Also I have a large attic fan I am wanting to install in the wall. It has louvers on it to hopefully seal the air and water out. I plan to use it to blow hot air out when I come home instead of cooling while at work. Then turn on the AC. Also plan to use on days that’s it’s not terribly hot as a method of cooling the whole house like my grandparents did. I live in East Texas so I won’t be able to do this too often. Is this ok or should I scrap this idea? Can I expect the louvers to seal good enough? With this would I need a mechanical ventilation system? Thank you for your awesome help. I’ve been reading your advice for years. CINDY in TYLER

DEAR CINDY: Thank you for your kind words and for being a loyal reader. Your solve is for your HVAC vendor to design and install a system to remove excess humidity from your interior air, otherwise you can expect to have some nasty condensation issues in your home.

DEAR POLE BARN GURU: What size posts should be used for 30′ x 40′ x 10 with 6/12 pitch in southern lower Michigan??? Storage/ garage / shop. STEVE in MARSHALL

DEAR STEVE: Looking at your most recent quote for a 30′ x 48′ truss bearing columns would be 6×6 solid sawn. We will be converting all of our roof supporting columns to glulams in a few months, then it would become 3ply 2×6 glulams.

This entry was posted in Ventilation, Footings, Insulation, Building Interior, Pole Barn Questions, Pole Barn Design, Pole Barn Planning, Pole Barn Heating, Trusses, Barndominium and tagged spray foam, attic fan, post frame insulation, columns, pressure preservative treated columns, moisture barrier, insulation, vapor barrier, HVAC on July 3, 2024 by admin.

High Humidity in a Pole Barn Home

High Humidity in a Pole Barn Home

Reader SAM writes: “I had a pole barn home built before pole barn homes became so popular. A concrete floor was poured around the 6×6 posts, and wooden trusses make up the roof. The pole barn walls have 2×6 purlins, and the roof has 2×4 purlins. Fiberglass insulation with a plastic vapor barrier sandwiched between the metal and the purlins. The vapor barrier is facing inside the structure, and the fiberglass is against the metal. I had living quarters framed inside the pole barn. The living structure is typical house construction with 2×4 walls, bat insulation in the walls, drywall, and cellulose blown over the ceiling joist of the living space. The living space has an HVAC with the air handler installed above the living space mounted between the trusses. When the structure was first built, the builder did not allow for any roof ventilation and no overhang or soffit vents to bring in fresh air. We started having high humidity inside the living space, even with the HVAC. Over the years, I had several HVAC companies evaluate the problem, and no one could give me an answer or solution to the problem. I removed a strip of the insulation and vapor barrier along the ridge cap and at the gable ends of the barn. I installed a vented ridge cap and used a cor-a-vent type vent installed under the gable rakes to provide ventilation up the gable walls and into the barn. I am considering installing another cor-a-vent product under the fascia along the walls to allow more airflow into the pole barn and attic space along the barn’s length. The concrete slab never appears wet on the garage side of the barn. Also, I have never noticed the flooring inside the living space being wet or damp. Do you have any ideas on why I am having the high humidity in the living space and what I can do to correct the problem?”

First why….

Everyday activities like cooking, washing, and showering can contribute to humidity levels.
Humidity levels can be affected by simple activities taking place in a household every day. These tasks can naturally add more moisture to air. Cooking and running a dishwasher can add more water vapor to kitchen air. Long, hot showers add a lot of moisture to bathrooms. Keeping areas ventilated by opening a window or installing an exhaust fan can lower humidity inside. Certain appliances, such as clothes dryers and stoves, need to vent to outside. A whole-house dehumidifier can also help eliminate some moisture created by these activities.

Leaks coming through cracks in plumbing system.
An interior plumbing leak from a bathroom or kitchen sink can cause increased moisture. Check pipes for cracks and corrosion.

Moisture from soil under your concrete slab.
If there is not a vapor barrier under your concrete slab, this can be a major source of moisture. This is called rising damp. Ineffective grading can be a significant factor since groundwater and rain can accumulate under your home. Gutters and downspouts should direct outflow at least 10 feet away from exterior walls. Ground outside your building should slope away at least six inches in 10 feet.

Your AC unit may be too big for your home.
Bigger isn’t always better: An oversize central AC unit may be reason for excessive moisture in a home. Evaporator coils found inside AC units act as a dehumidifier and pulls humidity from the as it runs. However, if a unit is too large, it may cool a room or home too quickly, running for only 10 to 15 minutes on a hot day before it abruptly shuts down. This is commonly referred to as short cycling. A longer runtime is needed to dehumidify a home correctly.

And then your likely solution:
I am surprised none of your HVAC professionals have recommended an ERV (Energy Recovery Ventilator). An ERV system will keep your indoor relative humidity at a desirable level.

This entry was posted in Pole Barn Heating, Pole Barn Questions, Barndominium, Pole Barn Design, Roofing Materials, Pole Barn Planning, Ventilation, Concrete, Building Interior, Insulation and tagged high humidity, Energy Recovery Ventilator, insulation, vapor barrier, Ventilation on June 20, 2024 by Rick Ochs.

Wall Insulation for a Hybrid Building

Wall Insulation for a Hybrid Building

Reader MASON in HILLSBOROUGH writes:

“I read your blog often and I truly appreciate the wealth of knowledge you openly share. I am in the process of starting construction on a hybrid steel shop that will house a small apartment that the wife and I will move into once its finished. We will sell our current home and then build a smaller house adjacent to the shop. 50 X 80 with 24′ wide mezzanine on one end. My questions are centered around wall/roof construction as well as proper insulation. Roof: I plan to install a standing seam roof with ice/water shield over 5/8 plywood. As you are aware, with hybrid steel it is hard to ventilate the roof with this type of construction. This downfall didn’t outweigh some of the benefits so this is what I am stuck with. Would like to understand some insulation options. Note: I do have the building designed to handle the loading of a couple of cupula’s and have considered making these passive and active ventilation points. (Exhaust fans with some louvers that I have yet to get the details figured out on)Walls (2 options): (Note: I prefer not to plan or have to always be fully conditioning the shop to 72 degrees…..I plan to have that ability by mechanical means but I don’t want to consistently have to be conditioning that much space, therefore I think i prefer the building to be able to breath out to the perimeter. I realize this may be tricky between the roof type and wall type)Option 1: metal siding – would like some input on wall and insulation construction based on the above notes of conditioning. Option 2: Hardie board vertical board and batten walls. Same as above, would like your input. There will be components on the first floor and second floor that make up the apartment space. Our approach on insulation and wall construction may change within those enclosed spaces may vary as they will be conditioned separately from the open shop space. Hope you can help shed some light on this approach and again thank you for your time and knowledge. Thanks!”

Thank you very much for your kind words!

In Orange County, being Climate Zone 3A, I would most often recommend drying to inside, using closed cell spray foam to insulate underside of roof deck and applied directly to wall steel. This does entail having to mechanically dehumidify.

Given your desire to dry walls to exterior, here are my thoughts:

Have a well-sealed vapor barrier under your slab on grade – you want as little moisture as possible entering building.

Include eave overhangs of at least two feet – this is again about moisture. You want to push weather (water) away from base of building.

Install continuous gutters, draining at least 10 feet away from building foot print.

For wall construction – regardless of siding being used, place a drainable housewrap under siding (make sure it is omnidirectional, so you can install either vertically or horizontally). Use bookshelf wall girts to minimize deflection and create an insulation cavity. Unfaced Rockwool insulation to completely fill insulation cavity. Well-sealed interior vapor barrier.

This entry was posted in Ventilation, Building Interior, Insulation, Pole Barn Heating, Pole Barn Questions, Pole Barn Design, Barndominium, Pole Barn Planning and tagged vapor barrier, housewrap, wall insulation, post frame insulation, gutters, close cell spray foam on May 28, 2024 by Rick Ochs.

To Vapor Barrier a Ceiling, or Not to Vapor Barrier a Ceiling.

To Vapor Barrier a Ceiling, or Not to Vapor Barrier a Ceiling.

Reader RAY in LAPINE writes:

“Hello, I live in Central Oregon, in climate zone #5. We are located in the High Desert at 4400 ft. The climate is dry with low humidity, occasional snow and cold in the winter. The summer temps are around 80 degrees, with large day to night temperature swings. Our heating hours per year are listed at approximately 7500+ per year. I am wanting to install 2×6 stringers, along with blow in insulation, but so many things are conflicting in my opinion, regarding my building when it comes to vapor barrier, no vapor barrier, heating hours per year, ventilation, etc., so I need your professional opinion. I have a 24×48 Pole barn, with double trusses, rated for 7 pound on the bottom cord. The truss bottoms are at 16ft off the concrete floor and are spaced 12 feet on center. The metal roof panels have dripstop that was factory installed. The walls have house wrap, behind bookshelf girts and was installed when the building was erected. The building has a continuous vented ridge, no soffit vents and is heated using a new, large, catalytic wood stove. I want to heat the building approximately 5-10 days a month, 8 to 10 hours a day for approximately 4 months of the year. So my question is, because of the drip stop panel coating and local heating hours, do I need any form of vapor barrier at the ceiling level or on the face of the purlins to avoid condensation issues??? I was originally going to install 10 mil, fire retardant, mesh reinforced poly on the bottom of the 2×6 stringers/trusses, wall to wall and blow insulation on top of the poly, then install 1/2 plywood painted white. Then I read not to use poly or a vapor barrier under 8000 heating hrs. After reading that, I thought I would use a air permeable product like ADO Insulweb, attached it to the bottom of the 2×6 stringers/trusses and blow insulation on top of that to R38, then install the plywood as stated before. Based on what I’ve read, it sounds like I need to install gable vents to the recommended ventilation ratio. Please provide me with your input and advice. Thank you.”

Spent many a winter day on Mount Bachelor’s slopes back when I lived in Oregon (even 4th of July one year), so am familiar with your turf (my step-brothers also live in your immediate area).

Based upon your information, I would install ceiling plywood and then blow in insulation directly on top of it. Paint your plywood after it is installed and this should be a sufficient vapor retarder. You will need to add gable vents, in lower half of your attic space. For a 24′ x 48′ building, you will need at least 139 square inches of NFVA (net free ventilating area) in each endwall, in order to provide sufficient air intake. This may require more than a single vent in each end.

This entry was posted in Budget, Insulation, Pole Barn Questions, Roofing Materials, Barndominium, Pole Barn Planning, Trusses, Ventilation, Building Interior and tagged attic ventilation, moisture barrier, blown in insulation, gable vent, vapor barrier, net free ventilating area, ceiling insulation on May 9, 2024 by admin.

Vapor Barriers, Post Longevity, and Spray Foam

This Wednesday the Pole Barn Guru answers reader questions about the need for a vapor barrier, the longevity of properly treated posts, and the better spray foam between open and closed cell.

DEAR POLE BARN GURU: Hello Sir, hoping you can help answer a question I cannot get a straight answer on. Currently building a 30x40x14 building and have the walls and roof house wrapped with Kelly Clark Block It. Steel is going on the building now. I just ordered steel for interior ceiling and trying to figure out if I should add a vapor barrier to bottom of truss first. Thoughts? MATT in ILLINOIS

DEAR MATT: Block it is wrong product for under roof steel. It allows moisture to pass through and be trapped between it and roof steel. As long as you do not blow in cellulose, you should not need a ceiling vapor barrier.

DEAR POLE BARN GURU: I bought a pole barn that has been retrofitted to a house. The posts are in ground. I’m worried about future resell and longevity of the post. Also, I’m in a cold climate and wonder if a proper footing would help with heating. Is there any good way to retrofit from in ground post to stem wall or something similar. I’m sure it’s all possible if money was not an issue. I’m looking for an economical solution. Thanks!! NICK in WEST LIBERTY

DEAR NICK: Properly pressure preservative treated columns (UC-4B) should outlast anyone alive on our planet today, especially in climates (such as yours) not prone to termite infestations. As for improving ability to heat – dig a trench around outside of building at least two feet wide and two feet deep. Invest in 2′ x 8′ (or 4′ x 8′ to be cut in half lengthwise), R-10 EPS insulation boards. Attach vertically to exterior side of pressure treated splash plank with top of insulation even with top of interior concrete slab. Run another 2′ horizontally out away from building at bottom of vertical. Any portion of vertical insulation above backfill will need to be protected from UV rays. This should keep your slab from getting so cold, as well as help to avoid frost heave. If you are in an area prone to burrowing rodents, you should further protect insulation https://www.hansenpolebuildings.com/2021/03/rascally-rodents/

DEAR POLE BARN GURU: I am trying to decide whether to go with open cell or closed cell spray foam on my bare metal pole barn walls. I will be enclosing the walls with some material, most likely plywood. What are your opinions regarding the pros/cons (is one or the other worse for corrosion, condensation, other pertinent factors, etc.) of the two foam approaches? Thanks so much! TERRI in CHESTER

DEAR TERRI: Open cell spray foam allows moisture to pass through and condense against steel cladding. I would not recommend it being used unless a two-inch thick layer of closed cell was first applied, then add open cell for extra R value (and to deaden sound).

This entry was posted in Pole Barn Planning, Barndominium, Ventilation, Building Interior, Lumber, Columns, Insulation, Pole Barn Homes, Pole Barn Questions, Pole Barn Design, Roofing Materials and tagged open cell spray foam insulation, closed cell spray foam insulation, vapor barrier, spray foam, UC-4B pressurem Preservative Treated columns, steel roof moisture barrier, moisture barrier, UC-4B on April 3, 2024 by admin.

Help – My Hobby Shop Has Wall Condensation

Help – My Hobby Shop Has Wall Condensation

Reader EVAN in PHILADELPHIA writes:

“Hi there, I recently constructed a small 20x20x10 pole barn for use as a hobby shop (woodworking, etc.). The eaves have vented soffit and the roof has a ridge vent. On the interior I did a metal ceiling with blown in R-C38 Cellulose. The attic space seems to be ventilating very well and I have no concerns. However, for the walls, I am having some moisture issues and am curious what the best plan of attack might be. The building is wrapped in Tyvek, I then constructed horizontal studs that line up with the exterior purlins and filled the gap with R19 faced Batts. I taped all the seams and tried to seal it the best I could. I then covered the walls with wood panels. However, after some activity that created some moisture in the air of the shop, I decided to check the walls and found the back of the Tyvek and fiberglass insulation soaking wet in a couple spots. Now, granted, the spots I had access to were less than ceiled (Around a pipe) that would be a likely spot for the warm moist air in the shop to get to the cold Tyvek, But I am afraid it’s likely an all-over problem. I know this is probably one of the most common questions you receive but I’m curious what you would recommend? Should I pull the wood panels off and add a vinyl vapor barrier. Would it be okay to put a vinyl vapor barrier over top of the faced fiberglass? Is there any negative to adding a vapor barrier? For example, would the reverse happen in the summertime if the shop is air conditioned? Any thoughts would be appreciated, I wish the company that sold me the barn would’ve discussed all this beforehand! But, we will move ahead. Attached are pictures showing the wall construction.”

This one really is not your provider’s fault.

Your faced insulation is already a vapor retarder. Adding another vinyl vapor barrier over interior of it is unlikely to change your outcome (although it shouldn’t negatively impact anything – other than being a lot of work).

If you do not have a vapor barrier under your slab, seal top of slab.

You have a very small area, so it takes only a very small amount of excess moisture to create challenges. Invest in a good portable dehumidifier (we bought one for our house at Walmart) and run it any time relative humidity inside your shop is over 40%.

This should take care of your challenge.

This entry was posted in Pole Barn Heating, Uncategorized, Insulation, Pole Barn Questions, Ventilation, Building Interior and tagged hobby shop, insulation, vapor barrier, housewrap, condensation, tyvek on February 15, 2024 by admin.

Plastic Vapor Barrier, PermaColumn, and a Fire Resistant Barrier

This Wednesday the Pole Barn Guru answers reader questions about use of 6 mil plastic vapor barrier in Michigan, if Hansen provides the option of a precast concrete pier to keep columns out of the ground, build heights, and “if anything needed between interior PVC panels, closed cell spray foam and the exterior metal siding.”

DEAR POLE BARN GURU: I have a pole barn that I am planning on insulating. The trusses are 2 foot on center and it has a shingled roof, the outside of the pole barn is steel. I live in Michigan and I was wondering if it is a good idea to put 6 mil plastic on the bottom of trusses before I hang steel on the ceiling. I will be blowing in insulation up there later. KAL in HUDSONVILLE

DEAR KAL: You are in Climate Zone 5A, so a ceiling vapor barrier is not required by Code. Building scientist and founding principal of Building Science Corporation Joe Lstiburek states, “Plastic vapor barriers should only be installed in vented attics in climates with more than 8,000 heating degree days.” (More on degree days here: https://www.hansenpolebuildings.com/2022/11/what-is-degree-day/).

I would only recommend you installing a vapor barrier above your steel ceiling if you were to be considering blowing in cellulose insulation. Why cellulose? https://www.hansenpolebuildings.com/2022/10/cellulose-post-frame-attic-insulation/

DEAR POLE BARN GURU: Do you deal with post frame designs that: 1) use the precast column to keep wood out of the ground? 2) Deal with designs that are 20′ eave height to accommodate 2 story interiors. JONATHAN in ZANESVILLE

DEAR JONATHAN: We have had several clients provide their own pre-cast Permacolumns and they can be incorporated into our engineered designs. There is, however, a less costly option to explore: https://www.hansenpolebuildings.com/2018/04/perma-column-price-advantage/

We can engineer and provide up to 40 foot tall walls and three stories without needing fire suppression sprinklers, so 20 feet eave heights are not a problem.

DEAR POLE BARN GURU: Hello, my question, which I can’t seem to find a straight answer anywhere online. Is anything needed between interior PVC panels, closed cell spray foam and the exterior metal siding? The pole barn is located in southern Indiana. It’s used as a shop and being heated occasionally with a wood stove. BENJAMIN in INDIANA

DEAR BENJAMIN: As your PVC and closed cell spray foam are both flammable, I would use an intumescent fire proof paint on interior face of closed cell spray foam, then fill balance of wall cavity (if any) with rockwool batts. As an alternative to intumescent paint, you could place sheetrock between wall framing and PVC panels (panels will lay much smoother).

This entry was posted in Ventilation, Uncategorized, Concrete, Lumber, Footings, Insulation, Building Interior, Pole Barn Questions, Columns, Pole Barn Design, Pole Barn Heating, Pole Barn Planning, Barndominium and tagged spray foam, permacolumn, eave height, fire resistance, 6 mil plastic, climate zone 5A, fire resistant barrier, PVC, blown in insulation, insulation, precast concrete, vapor barrier on February 14, 2024 by admin.

Spray Foam Insulation on Interior Surfaces of Metal Panels

Spray Foam Insulation on Interior Surfaces of Metal Panels

Information excerpted from MBCI.com

When it comes to insulating a building envelope, there are various methods that can be used depending on the building’s purpose and the required level of insulation. However, combining metal roof and wall panels with spray polyurethane foam insulation (SPF) is widely considered one of the most effective ways to achieve secure, strong, and long-lasting insulation. Utilizing this method of insulation offers numerous benefits including the sealing of panel joints, creating a vapor barrier, providing thermal insulation, and producing air barriers.

One of the most notable advantages of utilizing SPF insulation is that it can be used to fill spaces in the panel assemblies and function as a key component of an air barrier system, effectively reducing air leakage. However, there are a few design parameters to be mindful of when considering the use of SPF insulation for metal roof or wall panels. The Spray Polyurethane Foam Alliance (SPFA) has conducted research on the installation of SPF on steel panels and has suggested the following best practices for applying SPF to the interior surface of metal panels:

Closed-cell foam is recommended due to its water-resistant capabilities.

SPF is a recognized insulation material to be used below and in contact with through-fastened metal roof assemblies.

The surface of the metal panel being sprayed should be free from moisture, lubricants, dirt, or other contamination.

The technique used to apply the SPF can affect the performance and appearance of the foamed panels.

Using a release fabric membrane between foam and a metal panel in a wall assembly is not recommended due to the potential of creating voids between the SPF and the wall panel.

There is potential for stress-induced deformation (or “oil canning”) on 29 gauge or thinner material. (This can be minimized by following the foam manufacturers’ recommended application technique.)

Always follow national and local code requirements for fire protection. Exposed SPF may require an additional thermal barrier or other means for fire protection.

Consider using an SPF contractor accredited by SPFA’s Professional Certification Program (1) (compliant with ISO 17024) to provide high-quality and safe installation of SPF insulation.

It is important that a certified foam spray technician applies SPF to the required insulation thickness to achieve the optimum insulation density, adhesion, and thickness. The recommended application method when applying the foam is to use the controlled thickness spray technique, commonly known as the “picture frame” technique. SPFA describes this technique as if someone were following through the motion of picture framing, in which the applicator surrounds the interior perimeter of the wall framing stud and allows the foam to rise along the stud. This technique can also help to prevent SPF from getting between girts and architectural metal wall panels which could cause metal deformation.

The thickness of the initial pass fillet during picture framing should be at least 0.5 inch and should not exceed the maximum pass thickness recommended by the foam manufacturer. The minimum thickness of the initial pass is specified to provide enough material to activate the blowing agent and initiate the cure. After picture framing the perimeter of the area, the applicator fills in the center of the cavity using the maximum thickness recommended by the foam manufacturer. Maximum pass thickness varies by foam formulation and is listed in the technical data for each SPF product. Excessive pass thickness can result in inferior quality due to the increase in foam temperature during curing. For most closed-cell SPF, the maximum pass thickness is 1.5 to 2 inches. It is important for applicators of closed-cell SPF to follow manufacturers’ installation instructions on pass thickness limits and proper cooling times between subsequent passes made if they wish to develop the desired total thickness of the insulation.

Installers are trained to check the substrate surface for moisture, dirt, oils, rust, or other conditions that can interfere with proper foam adhesion. It is also important to clean the surface of these contaminants prior to spraying the insulation. If there is uncertainty surrounding the amount of adhesion needed for a metal surface, this can be determined onsite using a pull-tester in accordance with ASTM (American Society for Testing and Materials) D 4541 (Standard Test Method for Pull-Off Strength of Coatings Using Portable Adhesion Testers).

When the time comes to change an outdated or damaged panel, many SPF contractors use a release material such as building wrap or fabric to allow for a seamless and pain-free swap out. However, it is important to keep in mind that the use of a release material poses the potential of creating air gaps between the back of the SPF foam and the metal panel. These gaps could allow condensation to accumulate between the SPF and the panel and framing members.

Closed-cell Spray Polyurethane Foam is a viable insulation material for the interior surfaces of steel and aluminum metal wall panels. This foam application can be highly nuanced, and there is a possibility of deformation, distortion, or oil canning if the application of the SPF is done poorly

This entry was posted in Pole Building How To Guides, Pole Barn Planning, Ventilation, Uncategorized, Building Interior, Insulation, Budget, Pole Barn Questions, Pole Barn Design, Pole Barn Heating and tagged pole building spray foam, insulation, vapor barrier, spray foam, condensation control, moisture barrier on December 28, 2023 by admin.

What Bubble Insulation Brand do you Recommend, if Any?

What Bubble Insulation Brand do you Recommend?

Reader ERICA in WEST COLUMBIA writes: “Is there a specific bubble insulation brand you recommend? We will be using this as our vapor barrier in the roof. I’ve seen posts about this type of insulation disintegrating, so I’m wondering if the claims are exaggerated or if in fact it could be a certain brand. Also we are wanting to have cathedral ceilings throughout our building. Our roof is made with metal trusses and wood purlins. We are using bubble insulation and some type of batt insulation. What is the best method to vent if we are not going to have an attic space?”

To use batt insulation between roof purlins requires a minimum of an inch of continuous air flow between roof deck (roof steel) and insulation. To achieve this, you would need to add framing (such as 2×4 placed flatwise) running from eaves to ridge, then another layer running opposite direction. You could then use a reflective radiant barrier (bubble wrap) between overlays and batt insulation between purlins, up to depth of purlins. This requires vented eaves and a ridge vent.

Instead, look at spraying two inches of closed cell spray foam directly to underside of roof steel (between purlins), then fill balance of purlin cavity with unfaced rockwool batts. This will get you a higher R value and save on material and labor for a lot of 2×4. You should not vent either eaves or ridge in this case.

As for bubble ‘insulation’ – it is not insulation, at best (when completely sealed) it is an effective vapor barrier. There have been real problems with white vinyl facing of reflective radiant barriers flaking off over time. We had this same problem with our first supplier (and, of course, they went bankrupt before problems showed up). After selling millions of square feet, we stopped offering any reflective radiant barriers to our clients.

Read more about reflective radiant barriers here: https://www.hansenpolebuildings.com/2014/04/reflective-insulation-wars/

This entry was posted in Pole Barn Design, Roofing Materials, Pole Barn Heating, Constructing a Pole Building, Pole Building How To Guides, Pole Barn Planning, purlins, Uncategorized, Ventilation, Insulation, Building Interior, Pole Barn Questions and tagged moisture barrier, wood purlins, rock wool batts, vapor barrier, bubble insulation, batt insulation, spray foam, metal trusses on December 19, 2023 by admin.

Attic Ventilation With Trusscore Wall and Ceiling Panels

Attic Ventilation With Trusscore Wall and Ceiling Panels

Reader STACY in NEW BERG wrties:

“Hi, I have a pole building 28’x48′ 16′ high eave height. It’s used as a shop and RV storage. I’m insulating it and planning on heating it with a pellet stove. I’ve read your posts in many instances about (NOT) using a vapor barrier in the ceiling. Ok, that’s great, less work. However, I’m planning on using a fairly new product by Trusscore, wall and ceiling panels. These are a PVC material and can possibly be viewed as a vapor barrier itself, they lock-in tight to each other. The shop roof is 1/2″ Plywood and Tiger paw vapor barrier under 26 gauge Standing seam metal roof. I have a Gable vent powered with an Attic fan programmable by temp and/or humidity. I guess my question is, since I should not be putting up a vapor barrier, and given this material I’m using for the ceiling, should I be adding any venting through the ceiling to allow warm moist air from the shop to pass through the attic space? Seems like that would be wasting heat but, the moisture needs to go somewhere, right? Thanks much.”

Trusscore came about in 2020, as an alternative to painted drywall. It is a ½” thick panel with an unique internal truss design combined with high-strength polymer formulation.

Polyvinyl chloride (PVC) is an exceptionally durable material. It has a service life of up to 100 years and can stand up to wear and tear coming with interior wall and ceiling panels in residential, commercial, and agricultural applications.

Scratch, dent, and damage resistance properties make Trusscore Wall and Ceiling Board a great drywall alternative.

Combining PVC material and an internal truss design, you have durable, impact-resistant wall and ceiling panels able to stand up to contact without showing dents, cracks, or damage.

Trusscore products can handle nearly anything being thrown at them. From high-traffic residential spaces, commercial kitchens, to barns and workshops. I will guess you are also insulating at ceiling level, directly above your PVC Panels. You are creating a building “drying to inside” meaning it will be necessary to mechanically dehumidify (reach out to a qualified HVAC provider), otherwise you will have serious condensation problems. I am also concerned about your attic ventilation – as unconditioned dead attic spaces require both air intake and exhausts, in correct proportion. Not following these requirements will likely result in premature degradation of your roof system, or at least mold issues. You can read more on ventilation requirements here: https://www.hansenpolebuildings.com/2023/06/274512/

*For those of you who are wondering, Trusscore is not necessarily for those who are faint of pocketbook. Expect to pay somewhere around four dollars per square foot for panels only – roughly 10 times cost of gypsum wallboard (sheetrock).

This entry was posted in Ventilation, Building Interior, Budget, Pole Barn Questions, Pole Barn Design, Pole Barn Heating, Constructing a Pole Building, Pole Building How To Guides, Pole Barn Planning, Pole Barn Structure and tagged Ventilation, attic ventilation, trusscore panels, wall and ceiling panels, vapor barrier on December 7, 2023 by admin.

Insulation and Vapor Barrier, Rich-e Board Insulation, and a Tear-Off

Today’s “ask the Guru” answers reader questions about best applications of insulation and vapor barriers, the Guru’s experience with Rich-e Board insulation, and how to avoid a “tear-off” of a roof by adding layer of framing and insulation on top of old roof.

DEAR POLE BARN GURU: Hello, I am building a pole building in northern Indiana, I am looking for advice on insulation/vapor barrier locations. I have installed Tyvek on the outside before steel, will be putting wall girts and steel on interior as well. Plan is to install plastic on the inside before interior steel then blow in fiberglass insulation down in walls from top and do attic as well. I am just thinking since houses are built the same way with breathable Tyvek on the outside and the vapor barrier on the inside. Is the right way? Looking to keep the building from sweating on the inside. Thanks MICHAEL in KENDALLVILLE

DEAR MICHAEL: Internal sweating is a function of many more things than how you detail your wall insulation (you are correct in having Tyvek on exterior, vapor barrier on interior). As your building shell gets tighter, moisture is going to be trapped inside and you may need to mechanically dehumidify in order to prevent condensation. Some considerations – have a well-sealed vapor barrier under your slab, grade outside of building at no less than a 5% slope for at least 10 feet. Properly vent eaves and ridge, in correct proportions. You may want to consider your choice of blowing fiberglass into your walls, as it will settle over time, leaving a cold spot at top of wall. It is also affected by moisture. I would recommend using Rockwool batts instead.

DEAR POLE BARN GURU: What’s your experience with Rich-e board insulation? TERRY in NORTHPORT

DEAR TERRY: I wrote an article about Rich-e board not long after product was first announced (https://www.hansenpolebuildings.com/2016/11/one-inch-insulation-r-50/). I reached out to them when I was looking at doing a tear off reroof of my then home at Newman Lake, Washington. I was unable to ever even be able to obtain a quote from them. As best I can tell, it appears this business has permanently closed.

DEAR POLE BARN GURU: I’ve got a pole building/residence I was wanting to avoid a tear off, was thinking of using roof hugger stand offs and wanted to insulate on top of old steel. Thoughts? Could go with 2” blue board I guess. Since you’re up at Newman lake, any thoughts on contractors in NE WA? Thank you. TERRY in NORTHPORT

DEAR TERRY: Hansen Pole Buildings’ warehouse had a 40 plus year old steel roof, it leaked water like a colandar. We also wanted to add overhangs to eaves and endwalls. In order to overlay our old roof (building is 96′ x 96′), we placed 2×8 rafters at each existing truss, fastening through into truss top chords. We then joist hung 2×6 purlins between each rafter. Although we did not insulate (building is cold storage), we could have placed R-30 Rockwool batts between purlins. As long as your underlying old steel roofing is able to withstand any shear loads imposed, then pretty much any well thought out design solution would work. Ideally, you should engage a Registered Professional Engineer to evaluate your current structure and design a best structural solution. Least expensive, provided you can access underside of roof, your least expensive will be a tear off. If you have an attic space, order roof steel with an Integral Condensation Control factory applied. Any contractor who you would consider hiring should be booked out for at least a year, if not longer, and will want a premium unless they just happen to live nearby.

This entry was posted in Pole Barn Design, Roofing Materials, purlins, Constructing a Pole Building, Pole Barn Planning, Pole Barn Structure, Rebuilding Structures, Insulation, Professional Engineer, Pole Barn Questions and tagged Rich-E-Board, tear-off roofing, insulation, vapor barrier, housewrap, tyvek on November 22, 2023 by admin.

Conditioning and Insulating a Shop/House in Spokane (Climate Zone 5B)

Conditioning and Insulating a Shop/House in Spokane (Climate Zone 5B)

My Social Media friend TYLER in SPOKANE writes:

“Hello Mr. Guru, I am planning to build a 48′ x 60′ post frame shop with a 48’x20′ finished living space inside and the remaining to be insulated and climate controlled shop space. I’m planning for 14′ floor to ceiling height in the shop area to accommodate 12′ tall overhead garage doors. I am thinking of doing an 8′ ceiling in the finished space with a framed platform ceiling so I could utilize the space above for storage. My question is how would you go about efficiently heating and cooling this building? I’ve seen that you’re familiar with Spokane Washington so I’m sure you’re aware the range of temperatures in the area. One would think it would be more efficient to climate control the interior finished space on a separate system or zone than the shop area. The shop area would be okay having more tolerance in temperatures but would still need to be controlled. What type of HVAC/insulation solution would work best in your opinion? Thank you”

Radiant floor heat – have shop and living space on their own zones. www.RadiantOutfitters.com can set you up with the right products, done the right way. If you can afford to do so, go with geothermal (https://www.hansenpolebuildings.com/2016/12/modern-post-frame-buildings-geothermal/) as you can use it for both heating and cooling.

Insulation – Spokane is in Climate Zone 5B. Under slab, you want a well-sealed vapor barrier of at least 6mil (thicker is better and less likely to puncture while placing insulation, etc.). Code requires R-5 under slab insulation, however most people use R-10 under heated slabs. Slab edge insulation is required, but need not extend below slab, if heated.

Walls – from out to in: Weather Resistant Barrier (housewrap), bookshelf wall girts, R-30 unfaced Rockwool batts (fit perfectly with 2×8 girts), well-sealed 6mil interior vapor barrier.

Ceiling – vent eaves and ridge in proper proportion, order roof steel with an Integral Condensation Control factory applied, raised heel roof trusses to allow for full depth of blow- in R-60 insulation from wall-to-wall.

This entry was posted in Pole Barn Heating, Insulation, Pole Barn Questions, Shouse, Pole Barn Planning, Shouse, Building Interior, Lofts and tagged Radiant Outfitters, raised heel roof trusses, vapor barrier, unfaced rockwool batts, housewrap, Climate Zone 5B, bookshelf girts, heated slabs of concrete, blow-in R-60 insulation, geothermal on August 24, 2023 by admin.

Retrofitting for an Interior Workshop

Retrofitting for an Interior Workshop

Loyal reader LAURI in NORTH BRANCH writes:

“Thank you ahead of time for your generous gift of answering these questions. I love your blog. I have a 40 x 60 pole barn and doing an interior workshop of 25 x 40. Exterior walls (only in workshop area) have no vapor retarder and have R15 in Owens Corning pink board topped with 3/4″ plywood. I put in a tin ceiling (in the workshop area only) with no vapor retarder. I have not insulated the attic area above the workshop yet. It is well ventilated with eave and ridge vents. I put in a 2 x 6 partition wall which will separate the workshop area from uninsulated storage area. I will infrequently be using some form of AC on the hottest MN days and only occasionally use some form of heat (forced air, Mr. Heater or torpedo heater) to heat the workshop. The floors are sealed but without a vapor retarder under the concrete. I’m torn on what to do with the partition wall insulation. Vapor retarder or no Vapor retarder on the shop side? The interior shop wall covering will be 3/4″ plywood and the storage side will be OSB I have on hand. I’m thinking a wool product for minimizing any potential for mold. What insulation should I use for the attic space at truss chord level? I think you lean towards a blown in but can I leave the underside of the roof uninsulated? Vapor barrier or no vapor barrier on interior partition wall? What questions am I not asking that I should be? Thanks again for your wisdom. Nice to feel that someone has our interests at heart. Wish I would have found you guys before I built. Maybe a second one will be in our future where we can pay back the kindness.”

Mike the Pole Barn Guru says:

Thank you for your kind words, they are greatly appreciated.

My goal is to always try to assist people from making crucial mistakes they will regret forever.

My concerns for your workshop area are going to be ones of moisture – although your slab on grade has been sealed, it has no vapor barrier underneath, so you are probably yet going to have moisture passing through. Heating with either propane or kerosene will be adding even more moisture into this area.

I would look at design solutions allowing moisture to pass out of your workshop, and not in. For those interior walls, unfaced Rockwool batts, with a housewrap on the cold storage side of studs. Ceiling, if you can find it, use blown granulated Rockwool, as it is unaffected by moisture. Otherwise use Rockwool batts, overlaying layers 90 degrees to each other.

If you have no thermal break between roof purlins and roof steel, you are likely to have some condensation challenges, even if well ventilated. Keep a close watch and if you see condensation beginning to form, have two inches of closed cell spray foam applied to the underside of roof steel, otherwise it will rain on you.

This entry was posted in Insulation, Pole Barn Questions, Pole Building How To Guides, Pole Barn Planning, Concrete, Building Interior and tagged unfaced rockwool batts, vapor barrier, closed cell spray foam, rock wool batts on August 15, 2023 by admin.

Converting an Unfinished Wood Frame Steel Building

Converting an Unfinished Wood Frame Steel Building

Reader GEOFF in WILLISTON writes:

“ Mike, I think I came across a response on the internet of yours to a question about installing liner panels on the bottom chord of trusses and blowing insulation over the top. If memory serves me the question included the position of the vapor barrier on the liner side of the insulation. You had also recommended 2″ of spray foam on the underside of the roof panels to control condensation. My customer is converting an unfinished wood framed metal building into an equipment wash bay. I’m recommending spray foam on walls with liner panels over and liner panels affixed to the bottom cord of the trusses above. Do you think a vapor barrier on the bottom chords before liner panels, then blown insulation and spray foam on the underside of roof panels, and some power venting of the “attic” space should be about as effective as can reasonably be expected? (Trusses at 6′ O.C. with some supported added between.) “

I tend to agree with building scientist and founding principal of Building Science Corporation Joe Lstiburek.

Joe stated, “Plastic vapor barriers should only be installed in vented attics in climates with more than 8,000 heating degree days.”

Read more on degree days here: https://www.hansenpolebuildings.com/2022/11/what-is-degree-day/

What is Degree Day? – Hansen Buildings

According to Joe Lstiburek, “Plastic vapor barriers should only be installed in vented attics in climates with more than 8,000 heating degree days.”

www.hansenpolebuildings.com

In our climate, I would only install a ceiling vapor barrier above steel liner panels if I was intending to use blown cellulose for attic insulation. This is due to chemicals added to cellulose to prevent combustion tend to degrade steel if moisture is present. I would much rather see blown in granulated rockwool (my first choice) or fiberglass.

Attic ventilation is going to be critical here and is best resolved with adequate eave and ridge vents, rather than trying to be reliant upon an exhaust fan or fans.

This entry was posted in Ventilation, Insulation, Constructing a Pole Building, Pole Barn Structure, Trusses and tagged bottom chord of trusses, insulation, vapor barrier, condensation, blow in insulation, spray foam on July 18, 2023 by admin.

Looking for Advice on Insulating My Pole Barn Walls

Looking for Advice on Insulating My Pole Barn Walls

MATTHEW in CENTRAL ILLINOIS writes:

“Hello! I am a member of the Facebook pole barns and buildings page and see your post with advice often. I honor your opinions. I am wondering if you can help me out. I have a 30×48 pole barn in central Illinois. Concrete floor. I don’t believe there to be a moisture barrier under the concrete. I am wanting some advice on how to finish the inside. I’m thinking about doing bookshelf girts instead of interior girts attached to the poles. Should I use 2×4’s or 2×6’s? My thought is 2×6’s, but should I put them up against the exterior girts, or away from them to allow a space for insulation? There is no house wrap or vapor barrier on the inside of the metal. I would like to heat it as needed during the winter, but only when I’m working on a project. I wouldn’t have continuous heat. What insulation would be safest to use to prevent moisture along with being somewhat affordable? I do have a place about a half mile away that sells factory seconds of various foam boards. I have also heard good things about rock wool. Spray foam seems to be the most popular, but also can be more expensive. What are your suggestions taking in consideration of no current vapor barriers, location, and intermittent usage? “

Thank you for reaching out to me. Please message me any time with questions.

If unsure of whether there is a vapor barrier under your concrete slab, start by sealing it.

Here is how: https://www.hansenpolebuildings.com/2019/02/how-to-properly-apply-post-frame-concrete-sealant/

This sealant came highly recommended: https://www.hansenpolebuildings.com/2018/11/siloxa-tek-8505-concrete-sealant/

2×4 #2 bookshelf girts should be stiff enough on your small span between columns to prevent undue deflection of interior finishes, as well as limiting thermal transfer. Hold them flush to the inside of existing wall columns.

I would look to fill your insulation cavity with Rockwool batts, with a well-sealed vapor barrier on the interior.

This entry was posted in Insulation, Pole Barn Questions, Ventilation, Building Interior, Workshop Buildings, Pole Barn Heating and tagged closed cell spray foam, rock wool batts, vapor barrier, foam boards, house wrap on July 6, 2023 by admin.

Pole Barn Conversion, Condensation Concerns, and Setting Trusses

This week the Pole Barn Guru answers reader questions regarding converting a section of an existing building into living space, concerns about condensation in an insulated wall, and a concern about setting trusses too soon following a concrete pour.

DEAR POLE BARN GURU: Hello! We have a pole barn already built, 60×80, and we’ve decided to build living quarters in a 30×60 portion of the barn. We want to put a second level in the living quarters. We’ve done a 2ft monolithic pour that extends to the footings, around the exterior, 6-8inch thick concrete with steel grates underneath. We’ve done a 2ft by 3ft thick concrete footer underneath each pole. There are 16 total. Is this something that could be turned into engineered living space with a second story space (30×30)? Thanks in advance. KAITLIN in EDEN

DEAR KAITLIN: Most pole barns are built either without being engineered or to Risk Category I. For residential purposes, it would need to meet more stringent structural requirements of Risk Category II. You will probably have to add some perimeter slab insulation in order to meet Energy Code requirements. My best recommendation is to engage a Utah Registered Professional Engineer to do a physical evaluation of your existing building and to design needed structural upgrades.

DEAR POLE BARN GURU: Hello I recently built a post frame home and I have a question for you regarding the insulation on the walls. The exterior walls are 6×6 posts with 2×6 flat girts and a well-sealed WRB then steel. I used R-21 fiberglass with bookshelves girts on the inside of the wall then applied a 6 mil vapor barrier with acoustical caulk and tape to achieve a tight seal. Do you see any issues with this system in the long or short term as far as condensation and air sealing because of the lack of OSB or plywood sheathing on the outside? WESLEY in DULUTH

DEAR WESLEY: I have seen many far less well thought out wall systems without exterior sheathing not experience issues with condensation. As far as air sealing, you could get a blower door test done to find out exactly what your situation is. For extended reading, please see https://www.hansenpolebuildings.com/2020/10/blower-door-testing-your-new-barndominium-part-i/ and https://www.hansenpolebuildings.com/2020/10/blower-door-testing-your-new-barndominium-part-ii/

DEAR POLE BARN GURU: I am getting ready to pour my footing for my posts and am wondering how long I wait for the concrete to cure before setting the trusses, etc TRIPPE in NINE MILE FALLS

DEAR TRIPPE: We always suspend our columns eight (8) inches above bottom of holes and mono-pour footing and concrete encasement in a single pour (saves on paying for short haul charges). While concrete typically reaches 75% of compressive strength in seven days, when I was building we would pour one day and start building next day. For slabs on grade, it is recommended to not walk on them for 24-48 hours after a pour. Keep in mind, concrete compressive strength is in psi (pounds per square inch) and soil bearing capacity under footing is in psf (pounds per square foot). Most soil will support a maximum of 2000 psf or 13.88 psi, so your concrete (at 2500-3000 psi) is going to be much stronger, even after a very short time span, than soils beneath. You can increase concrete strength by ordering a higher cement mix and speed curing time by use of hot water (avoid use of chemical additives to speed curing).

This entry was posted in Pole Barn Planning, Professional Engineer, Columns, Lofts, Pole Barn Homes, Trusses, Post Frame Home, Ventilation, Barndominium, Concrete, Footings, Insulation, Rebuilding Structures, Constructing a Pole Building, Building Interior and tagged concrete pour, insulation, vapor barrier, condensation, setting trusses, occupancy classification, R-1, pole barn conversion, residential addition, R-III on June 21, 2023 by admin.

Dead Air as an Insulator

Dead Air as an Insulator

Are you considering building a climate controlled post-frame building? If so, then proper insulation is (or should be) at the top of your list.

If you have not seen ridiculous claims of double digit R-values from reflective radiant barriers yet (aka ‘bubble wrap insulation”) you will. Read more about these claims here: https://www.hansenpolebuildings.com/2014/04/reflective-insulation-wars/

Reflective radiant barrier manufacturers base their R-value claims upon an assembly including a 100% sealed dead air space on one or both sides of their products. In all reality, it is impossible to achieve this in real world construction.

For many years buildings have been built with an air space between building cladding and batt insulation in wall cavities. This air space did, in fact, help circulate air inside the wall and ventilate humidity through the wall. Now, as we increase wall air tightness quality and increase insulation levels, this air space no longer serves a ventilating function. Being on modern heavy insulation outside, it is too cold to help much with ventilation, and convection currents in this air space can actually make condensation problems worse. In addition, this air space is not a very good insulator. It is now recommended that all space between inside wall finishes (such as gypsum wall board) and outside cladding be filled with insulation, leaving no air space. Again – when insulating an exterior wall, don’t leave any air space.

Improper installation techniques with batt insulation can cost you 20% of an exterior wall’s insulating value from air spaces in hidden corners. This radically increases thermal bridging through framing members. If, on these same walls, you have an accidental space between insulation and vapor barrier, an air current can loop around insulation taking heat directly from warm interior finishes to cold cladding.

For an air space between wall insulation and interior finishes, vapor barrier location is critical. If an air space is between insulation and vapor barrier, air will rise because of building warmth. This air movement will find its way through or around insulation to cold side, where it will fall due to cladding’s colder surface. When insulation completely fills space between wall girts this looping is minimal. When insulation is installed less than perfectly, this looping force will accelerate. If there are open triangular corner spaces as mentioned above, this becomes a pump moving heat from interior finish to cladding as if there was no insulation there at all.

When there is an air space between vapor barrier and interior finish, nothing happens. Temperature goes from cool on bottom to warm on top but air in this space has no access to cold exterior cladding. It may circulate but it has no more effect than room air circulation.

Years ago walls were constructed to leave an air space between exterior wall framing and interior finishes. This was enough thermal break to stop condensation from forming on interior finishes in line with wall girts. With modern construction and heavier insulation, there is no longer a condensation problem on interior finishes caused by girts being cold. (There still is heat loss and in some climate zones building codes now actually require sheet insulation over all wall girts, either inside, or outside.) An air space’s insulating value is very small compared to the same thickness of any insulation.

Trapped air is an excellent insulator. Air moving freely carries heat. Circulating air, such as in a wall cavity, is effective at pumping heat from warm side to cold side. Not an insulator, in other words.

To be effective at isolating heat, air must be confined, trapped in tiny spaces, like in fibers of fiberglass, rock wool, or cellulose. Foam is particularly good at trapping air. So you take a not a very good heat conductor product and arrange for it to have many tiny cells able to capture air.

This entry was posted in Insulation, Constructing a Pole Building, Ventilation, Building Interior and tagged thermal break, cladding, radiant barrier, insulation, gypsum wall board, vapor barrier, convection, condensation, climate controlled, batt insulation, cold cladding, sheet insulation, Ventilation, thermal bridging on May 4, 2023 by admin.

Doggie Day Care

Hi Guru, I Need Your Guidance

Reader CHRISTINA in MILFORD writes:

“Hi guru, I need your guidance. I am looking to build a 30x135x14 commercial building for dog daycare. I have no experience in building/ordering a pole barn and want to get it right.

Bullet points: I need 4000 sq ft. broken down: 3000 for daycare with 1 garage, 1000 with garage for any type of renter to take an income. Side note: I did 14 feet for a car lift if renter was a mechanic. Question: is 30 wide the most cost effective width for my usage?

Insulation-would like it to be energy efficient: what is best to keep heat in? Spray foam or fiberglass. What rating/factors? Ceiling-thinking 10 ft ceiling to keep heat low. What’s best material for ceiling? Acoustical tiles 2×2, metal, or sheetrock. Will I need a vapor barrier? Spray foam, loose fiberglass bail or fiberglass rolls?

Gauge: what is the best gauge for my usage? Ventilation: what are soffit vents and do I need them in my structure in summer to release hot air from the ceiling. What is the best way to keep the structure cool/warm? Windows: would you recommend a window(s) high up that can be opened to have cross ventilation or a way to get rid of hot air? Concrete-radiant floor (hot water with pex) enough to keep dogs and employees warm or do I need a HVAC system too. Please include anything else I might have missed. Gotta get it right the 1st time. Thank you!!!”

Thank you for reaching out to me.

In answer to your questions:

Buildings closer to square are more cost effective than long, narrow ones. They reduce surface area of walls – so less expense in siding and interior finishes, as well as lower utility costs. Long, narrow buildings also put greater wind shear loads on roofs at each end as well as endwalls. This can result in a need to add structural sheathing to portions, adding to your investment further.

If you are considering your renter may be in automotive repair, you may want to consider a 40′ width, as it would allow for two standard vehicles to be parked inside end-to-end.

Pike County is in Climate Zone 5A

Under 2021’s IECC (International Energy Conservation Code) for commercial buildings Ceilings should be R-49, Walls R-20 plus R-3.8 continuous, slab R-15 three foot down at perimeter and R-5 under slab itself.

For roof system – order 29 gauge roof steel (https://www.hansenpolebuildings.com/2012/01/steel-thickness/) with an Integral condensation control factory applied (https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/), vent eaves and ridge in correct proportions (https://www.hansenpolebuildings.com/2018/03/adequate-eave-ridge-ventilation/), raised heel trusses (https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/), blow in R-49 of granulated rockwool (personally, I would do R-60).

Walls – commercial bookshelf wall girts (https://www.hansenpolebuildings.com/2011/09/commercial-girts-what-are-they/), Weather Resistant Barrier between framing and wall steel (think Tyvek or similar), unfaced Rockwool Batts with well-sealed 1″ Rockwool Comfortboard 80 applied to interior of wall framing.

Slab – at edges 4″ Rockwool Comfortboard 80 applied to inside face of splash plank and down vertically 3′. 1-1/4″ Rockwool Comfortboard 80 under slab.

I would use 5/8″ Type X drywall for the ceiling, without a vapor barrier. You will need to fire separate between rental shop and doggie day care. For the sake of making certain almost any occupancy will be allowed, plan on two layers of 5/8″ Type X on each side of the wall with no penetrations between.

Besides your radiant floor heat, I would also plan on an HVAC system capable of controlling humidity.

Most jurisdictions require a pre-application conference for commercial buildings, you will want to verify if this is available (https://www.hansenpolebuildings.com/2013/01/pre-application-conference/).

This entry was posted in Pole Barn Questions, Pole Barn Planning, Workshop Buildings, Commercial Buildings, Animal shelter and tagged sheetrock ceiling, insulation, vapor barrier, fiberglass insulation, spray foam, radiant floor heat, soffit vents on March 28, 2023 by admin.

Knee Bracing, Flying Gable Trim, and Ventilation Needs

This week the Pole Barn Guru answers reader questions about the removal of knee bracing to install interior ceiling and wall steel, a question about a special rake trim for a flying gable, and the possibility of adding ceiling liner panels to a structure and the need for a vapor barrier and proper ventilation.

DEAR POLE BARN GURU: Can I remove my knee bracing from the pole barn and put up interior ceiling and wall steel. I have a 60×104 pole barn on an 8″ wide 4′ high concrete wall with wet set braces (6×6 laminated beams. 8′ on center) ceiling is 16′ from floor my knee bracing takes up too much wall storage space. They brought them too far down the wall. About 6′. SEAN in MONTPELIER

DEAR SEAN: While knee braces generally cause far more structural harm, than good, they should never be removed without written authorization from whomever your building’s engineer is. If your building was not engineered (hopefully it was), then you should at least request written authorization from your provider including verification their removal will not affect any structural warranty.

In this article, another person dealt with similar issues: https://www.hansenpolebuildings.com/2015/11/can-i-take-out-knee-braces/

DEAR POLE BARN GURU: How do I trim out a metal ribbed roof panel on a barn with a widows peak? How do I make it match up with the rake trim? While maintaining proper drainage. KEVIN in LINCOLN

DEAR KEVIN: Your building kit provider should have had delivered to you one or more ‘special’ rake trims (one long side like a standard rake/corner trim, other flat with a hem) and some Emseal expanding closures. Here are your installation instructions: https://www.hansenpolebuildings.com/2016/05/9-steps-constructing-widows-peak/

DEAR POLE BARN GURU: I have a pole barn with a scissor truss (interior sloped ceiling) at 8′ on center. The builder placed insulation between the trusses and are kept from sagging by perpendicular metal straps approximately 2′ apart. When the breeze blows into the shop, the insulation batts float up and down like waves. I was thinking of installing a metal ceiling. I am concerned about the 8′ span between trusses and the possible need for a vapor barrier. What do you recommend? GREG in HUDSON

DEAR GREG: Hopefully you have vented eave soffits and ridge cap in correct ratios as lack of ventilation or too much or too little in wrong places can cause challenges (please read more here: https://www.hansenpolebuildings.com/2018/03/adequate-eave-ridge-ventilation/).

In your Climate Zone a ceiling vapor barrier should prove unnecessary. While I would not span eight feet with ceiling liner panels, I do see it being done successfully by many builders and specifiers.

This entry was posted in Insulation, Building Drainage, Pole Barn Questions, Building Interior, Pole Barn Design, Building Overhangs, Roofing Materials, Constructing a Pole Building, Pole Barn Planning, Trusses, Ventilation and tagged Ventilation, vented soffit, rake trim, vented ridge, liner panels, expandable closures, vapor barrier, Knee bracing, flying gable rake trim on February 22, 2023 by admin.

Why Fiberglass Insulation Doesn’t Work

Why Fiberglass Insulation Doesn’t Work

This article includes information in italics from a paper from Rastra.com, a provider of ICFs. For those interested, to read their paper in full please visit: https://www.rastra.com/docs/sales/Why_fiberglass_insulation_doesnt_work.pdf

I have been scouring insulation, vapor barrier and building envelope sources for months now, trying to get to truthful data I can rely upon. Let me tell you – it has been a task, and there are moments when I felt blood would squirt from my eyeballs!

“Fiberglass insulation is considered the standard in new construction. Unfortunately, fiberglass has serious flaws. Some of these may surprise you.

Let’s begin with this… it’s a little known fact that fiberglass insulation loses as much as 40% of its insulating capacity when outside temperatures fall below 20 degrees F. When this happens, R-19 fiberglass insulation performs as if it were only R-9. LEED confirms through a Canadian cold weather study that fiberglass loses half its R-value below 0 F. When you need it the most fiberglass insulation cannot properly insulate.”

While fiberglass insulation may lose some small percentage of R value in cold temperatures, this Oak Ridge study is very old news and no longer is pertinent (please read more here: https://www.hansenpolebuildings.com/2021/10/blown-in-fiberglass-attic-insulation/).

Andre Omer Desjarlais at Oak Ridge Laboratories was contacted about this issue, and he said, “This was true 20 years ago but all fiberglass manufacturers have changed their products appreciably since then and this is simply no longer an issue.”

I have searched high and low and cannot find this supposed Canadian cold weather study.

“Fiberglass also performs poorly in the presence of humidity within a wall cavity higher than just 30%. In winter this leads to condensation of moisture carried in by warm air through leaks through the wall. This raises humidity levels inside the building.”

This paragraph frankly makes no sense. I am finding no studies to back up fiberglass insulation performing poorly in high humidity. Condensation in walls can by minimized or eliminated by a well-sealed interior vapor barrier and/or using a flash and batt system with appropriate ratio of R value of closed cell spray foam applied to interior of siding, compared to batt insulation. Ratios are determined based upon the Climate Zone. If using flash and batt, mechanical dehumidification is necessary as walls will dry to the inside of the building.

“Once fiberglass insulation becomes damp its performance decreases dramatically. In fact, it only takes a 1.5% increase in moisture content in fiberglass to reduce its R-value by up to 50%. When moisture is trapped in a conventional wall cavity insulated with fiberglass and sealed with a vapor barrier, insulation becomes damp and loses its ability to insulate. This also promotes mold growth and leads to structural damage.”

I love “it fact” especially when I cannot locate any research to back it up! Regardless of insulation type, just keep wall cavities dry by use of properly placed Weather Resistant Barriers between framing and siding and well-sealed interior vapor barriers/retarders (when using batt insulation and not closed cell spray foam).

“Yet another problem with fiberglass is that for it to work it must be fully expanded to allow its air pockets to perform.”

From Bruce Harley (energy efficiency expert at Conservation Services Group), “When you compress fiberglass insulation, you increase its R-value per inch, up to a pint. However, when you compress a batt of a particular thickness, the total R-value does decrease. For example, standard low-density batts at their nominal rated thickness – R-19 at six inches – have an R-value of about 3.1 per inch. If you compress a 6-inch R-9 batt into a 3-1/2 inch cavity, you get about R-14, or 4.0 per inch.”

“Lastly, fiberglass wall insulation is designed to be used in framed walls. Everywhere a framing member is placed creates a thermal break between the pieces of insulation that allows air to pass. If 2x4s are used to construct the wall anywhere a 2×4 is positioned the wall only has an R-value of R-3.5. On average 27% of a building’s exterior wall’s surface is made up of 2×4 framing members with an R-value of only R-3.5.”

Assuming 2×4 studs at 16” on center, a stick frame wall would be roughly 10% not 27% (27% would take studs under six inches on center). In post frame construction with 2×8 bookshelf girts 24” on center, on a 10’ tall wall only 5% of wood members contact both interior and exterior surfaces, with 2×8 girts having an R-8.7 (per Green Building Advisor). Balance of the cavity could be filled with R-22 of fiberglass or R-30 Rockwool.

Calculating assembly R-values from ASHRAE:

Weather Resistant Barrier = .17
Interior Air Barrier = .68
½” gypsum board = 0.45

((1/22) x (.95)) + ((1/8.7 x (.05)) = .0489 = 1/.0489 = R20.4 + 1.3 = R-21.7 with fiberglass

((1/30) x (.95)) + ((1/8.7 x (.05)) = .0374 = 1/.0374 = R26.7 + 1.3 = R-28 with Rockwool

Moral of this story, fiberglass does work, however it may not be your best design solution.

This entry was posted in Insulation, Pole Barn Design, Pole Barn Planning, Ventilation and tagged Andre Omer Desjarlais, vapor barrier, condensation, fiberglass insulation, humidity, closed cell spray foam, dehumidification, flash-and-batt on January 24, 2023 by admin.

Purlin Spacing, Wall Insulation, and Roof Sheathing

This week the Pole Barn Guru answers reader questions about purlin spacing for 2×8 that span 17 feet, wall insulation recommendations, and if roof sheathing is needed for a new shop.

DEAR POLE BARN GURU: I need to span 17 feet with 2×8 purlins. Do I need to go 12 inch on center, or can I double 2x8s 24″ on center? Will deck with 7/16 OSB and install standing seam metal roof. BRAD in SPARTA

DEAR BRAD: IRC Rafter span tables are available online here: https://codes.iccsafe.org/content/IRC2021P2/chapter-8-roof-ceiling-construction

Scroll down to Table 802.4.1(1) (this would be for a minimal snow load).

Assuming 2×8 #2 Southern Pine 24″ on center will span only 13’1″ (even 2×10 #2 will only span 16’6″).

Going to a spacing of 16″ on center 2×8 #2 Southern Pine will span 17’1″.

DEAR POLE BARN GURU: Hello, I am looking to insulate the walls of my pole barn and plan on putting up vapor barrier. I insulated the ceiling last year and used Tyvek® basically to hold up the insulation as I can’t afford the steel yet. My question is should I also put up a vapor barrier on the ceiling? Thanks in advance, I appreciate the guidance as this is not my expertise. CHAD in GENESEO

DEAR CHAD: Henry County is Climate Zone 5A.

For your walls, I would recommend unfaced Rockwool either R-30 with a well-sealed interior vapor barrier or R-20 with R-5 well sealed continuous insulation boards on the interior (Comfortboard® 80 or EPS).

As you have under 8000 heating degree days, a ceiling vapor barrier would not be required. Hopefully your attic insulation is Rockwool as fiberglass is affected by moisture and loses R value when exterior temperatures drop. Make sure your attic space is properly ventilated (https://www.hansenpolebuildings.com/2018/03/adequate-eave-ridge-ventilation/).

DEAR POLE BARN GURU: Hello, I am building a 36x50x12 shop with 5:12 roof pitch, that will be conditioned space. The plan is to build out the interior with 2 small bedrooms and a bath then the rest open floor. I am putting in a ceiling at 12′ and will insulate the walls and ceiling leaving the roof uninsulated. Building is located in South Central Texas near La Grange. Does the roof need sheathing and felt or can I just lay the metal roof directly on the purlins? What about adding house wrap to entire building, walls and roof? Being in Texas, heat is biggest factor and with the a/c pumping inside I want to keep attic space vented correctly to keep moisture from building up. I plan to have large soffits to allow for soffit venting then ridge vent on roof. One of my biggest concerns is keeping out all the elements, including creep crawly bugs and concerned the garage doors will be source intrusions. It is my understanding that a sectional garage door is best for keeping out the elements vs roll up type. Can a garage door be truly sealed from all elements including bugs from crawling in? STEVEN in SUGAR LAND

DEAR STEVEN: Roof probably does not need to be sheathed unless your design wind speed is 140 mph or greater (Code requirement) or your engineer specified it. Do NOT housewrap roof, order roof steel with an Integral Condensation Control factory applied. Order raised heel trusses so you can have full attic insulation depth from wall-to-wall. While a sectional garage door is best, there is never a 100% guarantee of keeping crawling critters out – because you are going to open door at some point.

This entry was posted in Ventilation, Professional Engineer, Insulation, Pole Barn Questions, Pole Barn Heating, Pole Barn Design, Roofing Materials, Constructing a Pole Building, Pole Barn Planning and tagged roof sheathing, steel sheathing, rock wool insulation, purling spacing, roof load, purlin span, vapor barrier, roof sheathing OSB, wall insulation on January 18, 2023 by admin.

Vinyl Backed Insulation, Post Brackets, and Rebar Hairpins

This week the Pole Barn Guru answers reader questions about the availability of a tool for installation of vinyl backed insulation, pouring concrete prior to use of brackets and the limitations of “dry set” brackets, as well as setting vapor barrier once rebar hairpins have been installed.

DEAR POLE BARN GURU: Is there a tool out there that I can clip on the end of my vinyl back installation to pull it tight other than my hands. If so what would that tool be called and where can I buy it. I was hoping that there would be some type of alligator vice grips or something like that that we can attach and pull. MARK in OKLAHOMA

DEAR MARK: You are now finding one of many “joys” of using vinyl backed metal building insulation. You will want to read my personal metal building insulation story: https://www.hansenpolebuildings.com/2011/11/metal-building-insulation-in-pole-buildings-part-i/ and https://www.hansenpolebuildings.com/2011/11/metal-building-insulation/
In answer to your question – there is not such a commercially available product.

DEAR POLE BARN GURU: I plan to build a workshop with a concrete floor. a 24×40 x10ft building. Seems like it would be easier to just poor the concrete slab first and then just drill into the concrete and bolt the post brackets in place,,, rather than dig a bunch of holes and pour concrete piers for the post with wet set brackets…what are the advantages of setting all the posts first, then pouring a concrete floor later? Are there any disadvantages to bolting brackets to the concrete rather than using a wet set bracket? Ii am in a high wind area, (120 mph) and seismic area ‘e”. RON in HILO

DEAR RON: Problem #1 is dry set (bolted) brackets are not rated for moment (bending) forces, unlike wet set brackets. This becomes problematic, especially in areas of high wind.

Problem #2 – you can’t just pour a flat slab on grade, you would have to thicken slab edges to probably 18″

With wet set brackets, you can monolithic pour a slab with deeper excavation points at bracket locations, however I typically recommend waiting to pour slabs until after a roof is on to avoid heavy objects from falling and chipping your freshly poured concrete.

DEAR POLE BARN GURU: How do I install the concrete vapor barrier after the rebar hairpins in the columns have been placed?

Rebar Hairpins

Thanks! REID in WILLISTON

DEAR REID: Vapor barrier will go under rebar hairpins, so either block up one hairpin end or have someone lift it for you (this will cause other end of hairpin to raise) – slide vapor barrier under hairpin and up around sides of column. Seal vapor barrier to column and you are all good.

This entry was posted in Ventilation, Concrete, tools, Insulation, Columns, Pole Barn Questions, Constructing a Pole Building, Pole Building How To Guides and tagged wet set brackets, rebar hairpins, dry set brackets, drill set brackets, vinyl backed insulation, insulation, vapor barrier on December 28, 2022 by admin.

Think About Barndominium Insulation BEFORE Building

Think About Barndominium Insulation BEFORE Building

Regular readers are probably beginning to wonder why I have so many requests for information on how to insulate buildings AFTER they have been erected.

Me, too.

Insulation is crucial to your barndominium’s long term thermal performance. Doing it wrong can be expensive, both up front, as well as over lifetime of heating and/or cooling.

Reader JAMES in MILTON writes:

“Hello, I could really use your advice. I’m having a 48′ x 48′ wood barn built in Georgia with a 1,200 square foot apartment/ loft on the second floor. The purlins on the barn will be 8″ thick with 24″ spacing (center to center). The barn’s ceiling will be attached to the bottom (interior) side of the purlins. Plywood, the roofing underlayment, and the metal roof will be installed to the top (outer) side of the purlins. I’m looking to put insulation in-between the purlins to achieve (as close to) an r-40 insulation rating. Originally, I was going to get 2″ r-10 foam board insulation and layer them in between the purlins (up to the 8″), but prices for form board insulation increased again in my area and is having me rethink my plan (went from $40 to $60 a sheet). Plus, I would have to cut each foam board to fit in between the purlins, which is time consuming. I’m considering other options, but really don’t have the construction background to know which direction to go. From what I’ve read online, my setup would be an unvented space, limiting my options to spray foam (closed cell), foam board insulation or structural insulated panels (which goes on top of and not in between the purlins). I’ve also read I could install a layer of closed cell spray foam inside the purlins cavity but against the underside of the plywood. Afterwards, fill the rest of the purlin cavity with an air permeable insulation, such as faced fiberglass batts insulation. But I’m not sure if this option still requires venting. What is the best option when installing insulation in between purlins? Would foam board insulation work well? If so, other than cutting to size, would I have to do anything else? Thank you in advance for your help.”

Mike the Pole Barn Guru says:

Welcome to challenges of trying to get adequate insulation when finishing the underside of roof purlins.

Fulton County is Climate Zone 3A. 2021 IEEC requires ceilings to have a minimum R-49 – going to be tough to get unless you were to closed cell spray foam on the entire cavity.

You could do 2″ of closed cell spray foam directly to the underside of your roof deck (R-14), then fill the balance of the cavity with unfaced rockwool batts (roughly R-17). You do not want a vapor barrier below batts as this would trap air between two vapor barriers. Kraft facing on fiberglass batts is a vapor barrier and fiberglass is negatively affected by any moisture (even 1.5% moisture content can reduce R value by 50%).

Foam board will be highly labor intensive, difficult to air seal, provides a lesser R value than the same thickness of closed cell spray foam and at $60 a sheet, is approaching price of spray foam.

Another option would be to fill the cavity with unfaced rockwool batts (roughly R-23) then add two layers of 2″ R-10 foam board below purlins before your interior finish. It might be difficult to source rockwool batts 7-1/4″ thick, so may require doubling 3-1/2″ batts.

This entry was posted in Pole Barn Questions, Pole Building How To Guides, Pole Barn Planning, Pole Barn Structure, Ventilation, Barndominium, Insulation and tagged rock wool batts, IEEC, Kraft facing on fiberglass batts, vapor barrier, foam board, closed cell spray foam, roof deck, unfaced rock wool batts on December 13, 2022 by admin.

Saving a Poorly Designed Crawl Space

Saving a Poorly Designed a Crawl Space

Reader GEORGE in VIENNA writes:

“I am substantially replacing rotted parts of an existing building set on short 6×6 treated posts which are in good condition. above the posts it is conventional platform construction, and untreated. Unfortunately, the original builder set the building partially into the side of a hill in an attempt to use thermal mass and reduce energy use in its off-grid location. The uphill side was backfilled to a height of approximately 30″ above the interior floor, which is OSB over untreated 2×12 beams and untreated 2×6 joists. Skirting to keep out moisture was untreated plywood, poly sheet, and Styrofoam block insulation. In 6 years, there is substantial rot of the perimeter plywood, perimeter 2×12 rim joists, some 2×6 floor joists, some areas of the OSB flooring, the untreated sole plate and a few studs above. Otherwise the building walls, windows, doors, roof trusses, metal roof, insulation, etc., are well made and in good condition. We are temporarily supporting the building from below and removing the failed materials all the way around. We are removing the backfilled dirt on three sides to expose the posts and provide airflow underneath. All rim joists, beams, and floor joists will be replaced with treated materials. I am looking for advice in two areas (1) floor insulation, either under or over the OSB, and (2) treated skirting around the perimeter which would allow partial backfill and maintain ventilation.”

Mike the Pole Barn Guru says:

You really have two options:

You could condition your crawl space – this would require a 6mil or thicker, well-sealed vapor barrier to cover underlying soil and up perimeter walls to floor joists. There would be no vents with this method, however an air-circulating device must be provided. Perimeter walls should be insulated using either closed cell spray foam or rock wool batts.

From Building Code Section 308.3, Unventilated Crawl Spaces

The air-circulating device must move at least 1 cubic foot of air per 50 square feet of crawl space area. The crawl space floor area must be completely sealed with a vapor-retarding material. The edges of the vapor retarder must be lapped up against the inner foundation walls.

Read more about encapsulated crawl spaces here: https://www.hansenpolebuildings.com/2020/11/11-reasons-why-barndominium-crawl-space-encapsulation-is-important/
Or – have an unconditioned crawl space, where your vapor barrier would cover the ground surface. Insulation would ideally be beneath OSB – between floor joists. Again, same choices for insulation – just between joists. With this choice foundation vents would need to be added to perimeter walls.

Most building codes require 1 square foot of open ventilation area for every 150 square feet of crawlspace. Generally, Automatic Foundation Vents have 50 inches of net free area per vent. Therefore, install one vent for every 50 square feet of crawlspace.

FDN (Foundation) rated pressure preservative treated plywood will probably be your best skirting material.

This entry was posted in Insulation, Pole Barn Questions, Pole Building How To Guides, Pole Barn Structure, Ventilation and tagged crawl space, closed cell spray foam, rock wool batts, air-circulating device, encapsulated crawl space, vapor barrier, floor joists on November 29, 2022 by admin.

Corner Trim, Metal Roof Install Issue, and Insulation Solutions

This Wednesday the Pole Barn Guru answers reader questions about what trim to use on building corners, an issue of installing metal to roof that is extremely out of square, and best options to insulate a building.

DEAR POLE BARN GURU: Good afternoon! Looking to see what trim to use on the corners? https://www.hansenpolebuildings.com/2015/10/horizon-steel-siding/ Sincerely, KYLEIGH

DEAR KYLEIGH: Order standard Corner Trims and place pre-formed foam Outside Closure strips between horizontal steel siding and trims.

DEAR POLE BARN GURU: How much more difficult would it be to put the metal roof on if you can’t square the roof trusses. Because the posts were not cemented in properly. We are 8′ out of square on a 24’x50′. Would it be possible to square being that far out? TOM in BLOOMSBURG

DEAR TOM: I want my roof planes to be square within 1/8th inch before attempting to run steel. At 8′ out of square, I would have pulled out all offending posts and started over again. What you have will be impossible to properly roof and would require cutting every sheet of steel at eaves to even get a straight overhang line.

DEAR POLE BARN GURU: Just finished 40x60x16 pole barn and am looking to insulate. Building wrap was installed on exterior walls and roof has double bubble. Wondering how to manage moisture inside the building. Slab is insulated under as well as a vapor barrier. Interior walls and ceiling will be finished with steel liner panel. I’d like to spray foam entire building with open cell spray foam walls and roof deck. Would I need to install a vapor barrier between foam and steel liner panels? Building has attic trusses and the room will also be conditioned separately from garage space. Thanks KYLE in COXSACKIE

DEAR KYLE: I would not spray foam to building wrap, as it causes more problems than it solves. https://www.hansenpolebuildings.com/2020/04/spray-foam-insulation-3/
For walls, I would use unfaced rock wool batts, with a well-sealed interior vapor barrier. You do not need a vapor barrier between ceiling liner panels and attic spray foam. Personally, I would blow in fiberglass above ceiling liner panels and ventilate the dead attic space.

It might be necessary to mechanically dehumidify your building.

This entry was posted in Roofing Materials, Constructing a Pole Building, Pole Building Siding, Ventilation, Building Interior, Insulation, Pole Barn Heating, Pole Barn Questions, Pole Barn Design and tagged corner trims, unfaced rock wool batts, metal trims, insulation, install roof steel, vapor barrier, Ventilation, square roof on November 16, 2022 by admin.

Preventing Radon Issues

Preventing Radon Issues in Slab-On-Grade Barndominiums

I grew up in what is now Spokane Valley, Washington. Little did any of us know, back then, it turns out Spokane County is one of six counties in Washington State requiring radon mitigation measures in newly-constructed residences and residential additions. Radon is a natural in ground radioactive gas. It comes from decay or breakdown of uranium, a radioactive element in rocks and soil. Radon has no odor, color, or taste. Radon is the leading cause of lung cancer among nonsmokers.

Wonderful….not.

Building your new post frame home or barndominium in a radon sensitive area? There are some precautions to take to mitigate possible effects.

Passive radon mitigation systems can save lives. When properly installed, passive radon mitigation systems can keep radon levels down without radon fan. New barndominiums can be built radon resistant with a permanently installed passive radon system.
Although codes vary from town to town, there are six basic components of radon resistant new construction techniques:

Install a gas permeable layer before concrete slab is poured. This is usually a six inch layer of clean gravel. Gravel is very porous and allows for simple air movement below concrete slab. This will help your passive radon system move radon and other soil gas without restriction.

Install a vapor barrier above gas permeable layer before concrete slab is poured. A minimum 6mil plastic membrane is recommended (and Building Code required minimum for under slabs in conditioned buildings). Vapor barrier seams should be overlapped by at least 12″ and taped with high grade vinyl tape. My recommendation is a 15mil true vapor barrier, far superior (less prone to puncture) than 6mil visqueen.

install radon collection point with schedule #40 PVC pipe stub. Concrete will be poured around this pipe stub. It is extremely important to create a radon collection point unimpaired when concrete is poured. This is usually done by installing a soil gas collection pipe (drain-tile) or PVC tee.

Seal and caulk radon entry points. It is important to seal all visible concrete floor cracks, control joints and cold joints (where any foundation meets floor) using proper concrete caulk. If your home has a sump, it is a primary radon entry point and should be sealed air tight with a proper sump cover. Sump cover should be removable in case sump needs to be worked on. Plumbing roughs are another radon entry point and should be sealed with a cover. Once plumbing work is complete it is important to seal around pipes with concrete or expandable foam sealant.

Install radon vent pipe. When installing a passive radon system, it is important to install a radon vent pipe through an interior wall or flue chase. As your home warms this pipe, a natural stack effect will occur to pull air through the pipe; this in-turn pulls radon gas out of the soil. It is best practice to use 4″ PVC in radon resistant new construction to allow for maximum CFM in the event the system is activated. Radon suction pipe should continue through interior walls to attic space above home or building in a location allowing for future access. Vent stack should terminate through the roof at least ten feet from windows, doors or other building openings.

Install a electrical junction box within reachable distance of in attic radon vent pipe in attic. This will allow for an electrical source in the event the system is activated.

You may want to engage a radon mitigation contractor when using radon resistant new construction techniques. Radon contractors know how to properly move below building air. In many areas, plumbers are used to install passive radon systems. Often it is found that the suction point is placed in gravel and concrete has created a seal around the radon suction point location. This is dangerous because the new barndominium owner believes their home is built radon resistant yet passive radon pipe cannot move any air. If you have a home with a passive system, be certain to perform a radon test at least every two years.

If radon levels remain elevated after radon resistant techniques have been used, this passive radon system can easily be converted to an active soil depressurization system (active radon system). This can be done by adding a radon fan to the radon vent pipe in your attic space above.

This entry was posted in About The Pole Barn Guru, Pole Building How To Guides, Pole Barn Planning, Ventilation, Concrete, Footings, Barndominium, Shouse and tagged passive radon mitigation system, radon fan, radon, radon resistant, vapor barrier, radon gas permeable layer, radon collection point, #40 PVC pipe stub, sump pump cover, barndominium on October 6, 2022 by admin.

Can No Longer Afford Spray Foam for a PEMB

Can no Longer Afford Spray Foam for a PEMB

Loyal reader CINDY in TYLER writes:

“I had a steel building (20×18) built with steel frame and metal exterior. This is going to be my house. It will have a loft that is half the size of the building. Originally the builder talked me into spray foam and that’s what Ii planned to do. He said I had to use wood to frame inside the metal walls first, then run electrical and plumbing before the spray foam. That was a couple of years ago. Now that inflation has caused prices to soar, I am simply not able to afford the spray foam. My main concern is the condensation/moisture issue. i am doing the rest of the work by myself. Since I don’t have any help it’s not going to be feasible to remove wall panels to install house wrap or insulation. So I wanted to get your expert advice on how to handle this. Specifically I have a plan to run by you. So the idea is instead of building my framing inside the metal frame, move to the inside of the metal, attach wood frame to the inside edge of the metal frame. Insulate the inside of the wood frame and add a moisture barrier to the inside of the wood frame before drywall. I will lose 3.5″ of space all around the inside but i think that will take care of any moisture issues. Please tell me what you think about this plan and make any appropriate suggestions even if you don’t post this on your blog. Also I wanted to thank you for the wealth of knowledge you have readily available on your site. Can’t tell you how much help you have been.”

Mike the Pole Barn Guru responds:

Thank you for your kind words, they are greatly appreciated.

Normally (in your climate zone of 2A) I would be recommending closed cell spray foam as insulator of choice – due to a combination of heat and humidity. Your builder headed you in a correct direction.

Before we get into how to frame your interior, we need to address what is going to happen with your roof. With steel installed directly over framing (whether wood, or in your case steel), if there is no well-sealed thermal break, you are going to experience condensation issues. You are going to have to find a way to spring for two inches of closed cell spray foam sprayed directly to the underside of your roof steel. Steel frame and steel purlins should also be sprayed. If not, you are going to have condensation on them – steel is a wonderful conductor of heat and cold.

Now – on to your question at hand. For your walls, it appears most folks do exactly as you propose and build a 2×4 wood stud wall inside of their PEMB’s (pre-engineered metal building) steel wall girts. You will want to completely fill your wall cavity with insulation – I would recommend rock wool, as it is not affected by moisture (here is information on one particular product https://www.hansenpolebuildings.com/2013/03/roxul-insulation/). You want to make sure your interior vapor barrier is extremely well sealed, including outlets.

If you do not have a well-sealed vapor barrier under your slab on grade, please seal your concrete now. Your HVAC system should be designed to mechanically dehumidify, else condensation is going to haunt you forever.

This entry was posted in Pole Barn Planning, Building Interior, Insulation, Pole Barn Questions, Roofing Materials, Pole Building How To Guides and tagged steel purlins, insulation, vapor barrier, condensation, spray foam, thermal break, closed cell spray foam, rock wool, PEMB on August 25, 2022 by admin.

Condensation, Floor Plans, and Planning a House

This Wednesday the Pole Barn Guru discusses condensation issues in a metal pole barn a reader would like to convert to livable space, floor plans for a new post frame residence, and the steps to take to plan and build a new post frame house.

DEAR POLE BARN GURU: I just purchased a property with a metal pole barn on it. It has a concrete floor and is not insulated. I want to finish part of it off to make living space. Currently condensation will form on the bottom of the roof and I obviously can’t have that over my living space. Planning to frame out the portion I’ll use for living space, install kraft faced batt insulation and then drywall over that. Not planning on any additional vapor barrier on walls. Once I build the ceiling I plan on using blown insulation. How do I address the condensation/moisture issue from the roof in the most economical way possible and do I need anything additional on the walls? The cement floor seems dry enough but I don’t know if there is a vapor barrier underneath, how can I know if it’s dry enough and if it’s not what should I do? Thanks so much!! MARK in UNDERWOOD

DEAR MARK: You can easily check your concrete slab for a vapor barrier – place a wrench on floor overnight, next morning remove wrench and if a dark spot is seen where wrench was placed, you have no vapor barrier. If so, seal slab with a high quality sealant (here is an example https://www.hansenpolebuildings.com/2018/11/siloxa-tek-8505-concrete-sealant/).
For you roof, best solution is two inches of closed cell spray foam applied directly to underside of your roof steel. If you create any dead attic spaces, make certain they are well ventilated, ideally at eave and ridge.

On exterior walls, since you have no Weather Resistant Barrier (Tyvek or similar), I would recommend using rock or mineral wool insulation (https://www.hansenpolebuildings.com/2013/03/roxul-insulation/) as it is unaffected by moisture. Install a well-sealed clear poly vapor barrier between wall framing and drywall.

DEAR POLE BARN GURU: Do you do 6 bedroom Barndo’s? I’m looking for a 6 bed, 4 bath barndominum floor plan. I have an idea of what I like in my head but 6 bedrooms one story are difficult. HEATHER in CLEBURNE

DEAR HEATHER: We can provide any number or bedrooms and bathrooms, as every barndominium Hansen Pole Buildings provides is 100% custom designed to best meet the wants and needs of our clients and their loved ones. Please see #3 here to assist in determining needed spaces and approximate sizes, and to have professional floor plans and elevation drawings produced affordably.

DEAR POLE BARN GURU: I would like to build a 20 foot wide x 40 foot long pole barn house in Fredericktown, Ohio. Do you know if the local building department would give a permit for a residential pole barn house, & what are the steps to obtaining that permit, who to call, & etc.? I’m at the beginning of that building process & would like to begin this summer. Thanks. RENEE in MOUNT VERNON

DEAR RENEE: Here is some information you may find useful in getting started: https://www.hansenpolebuildings.com/2021/02/a-shortlist-for-smooth-barndominium-sailing/
You will need to contact your local Planning and Zoning office to begin with. You can look up appropriate office (depending upon your actual Township/Village/City) at www.KnoxRegionalPlanning.com. This should get you what you need to know from them: https://www.hansenpolebuildings.com/2020/01/your-barndominiums-planning-department/
Many jurisdictions do have minimum square footage requirements for dwelling, so you may be forced into more than your desired 800 square feet. You may also want to investigate building 24′ x 36′ as it is more efficient for materials usage.

If anyone tells you a fully engineered post frame home cannot be erected in their jurisdiction, get from them a copy of any approved ordinance to confirm (usually there is not one) and if it does exist, get it to me and I will go battle for you for free (I win 99% of these).

In many smaller communities, Planning, Zoning and Building Departments are a “one stop shop”. Here is what we will need from your Building Department: https://www.hansenpolebuildings.com/2020/08/building-department-checklist-part-i/ and https://www.hansenpolebuildings.com/2020/08/building-department-checklist-2020-part-ii/

This entry was posted in Building Styles and Designs, Building Department, Post Frame Home, Constructing a Pole Building, Barndominium, Pole Barn Planning, Shouse, floorplans, Ventilation, Concrete, Pole Barn Questions, Pole Barn Homes, Pole Barn Design and tagged Post Frame Home, shouse, vapor barrier, condensation, barndominium plans, Building permit, post frame floor plans, post frame building permit, moisture barrier on March 23, 2022 by admin.

Post Frame Plywood Slab-on-grade

Post Frame Plywood Slab-on-grade

As concrete and excavation costs have increased steadily buildings are more frequently turning to slab-on-grade foundations. These assemblies require less concrete and labor than full basements and have a number of advantages over crawlspaces: better thermal performance, much lower risk for water and animal intrusion, and lower maintenance overall. Slab-on grade foundations also make universal design easier to achieve.

In our ongoing quest to improve residential post-frame construction methods, we’ve embraced a number of new approaches to slab-on grade foundations, one of those approaches is concrete-free slabs.

WHY WE DITCHED CONCRETE

REDUCED EMBODIED CARBON

Concrete has a high amount of embodied carbon, and companies like ours specializing in high-performance, environmentally conscious construction are always looking for innovative ways to use less of it. Roughly 40% of all United States greenhouse-gas (GHG) emissions come from our buildings, 11% from carbon embodied in materials used to make those buildings.

One biggest single contributors to GHG emissions is concrete, responsible for 8% of total emissions on our planet. So it makes sense to reduce not only energy amounts used in operating our buildings but also concrete amount we use to build them.

FEWER DELAYS AND MOISTURE REDUCTION

A plywood slab is not only more environmentally sound than a full concrete approach, but it offers a number of practical benefits too. D-I-Yers can build slabs themselves, saving on costs and allowing to better control timelines, avoiding delays due to subcontractor schedules and more.

Unlike concrete, plywood slabs do not load significant moisture into building envelopes during curing processes.

HASSLE-FREE FLOORING

Another big advantage of a plywood slab is finished flooring can be installed directly onto it—no different than installing flooring on a plywood-and-joist floor. To install flooring on a concrete slab a vapor barrier must be applied over top with additional accommodations—such as wood sleepers and a plywood subfloor—depending on flooring chosen.

To make a plywood slab as durable as possible, choose a vapor-permeable flooring for slab’s largest areas. This allows any incidental moisture—from spills, toilet overflows, or whatever else happens above floor—to dry to interior and not build up in plywood. This said, we feel comfortable using impermeable flooring such as tile in smaller areas (kitchens and baths, for example) as long as it’s installed over a decoupling membrane to allow slab to flex and move below it and as long as there are adjacent permeable areas for plywood to dry to.

Bottom line: plywood won’t degrade as long as it has more of an opportunity to dry than it has potential for retaining moisture.

Start off on right footing

Building codes in many climate zones (3 or greater) require a minimum R-10 thermal break at concrete slab edges, where up to 60% of heat loss occurs. Compared to concrete, however, a plywood slab-on-grade has very little thermal loss at edges because it’s only 1-1⁄2 in. thick, and it’s wood. One could reasonably argue standard level of slab-edge insulation isn’t as necessary with a plywood slab-on grade. However, making this argument to your local building inspector might not be worth the accompanying headaches; as code has no guidance on anything other than concrete slabs.

LAYER 1: STABLE SOIL IS AN IMPORTANT FIRST STEP: First layer is native, undisturbed soil or engineered fill slab bears on. Most post frame buildings have no interior point loads, all bearing is on perimeter columns and their footings, and slab has no structural function. When we have a building with point loads or load-bearing walls on the interior, add interior footings, just as done with a concrete slab.

LAYER 2: CRUSHED STONE ACTS AS A CAPILLARY BREAK Second layer is a minimum four inch compacted, 3⁄4-in. crushed stone with no fines. Its primary function is to act as a capillary break, preventing moisture from being wicked up through the slab and into the building. This second layer also functions as a “pressure field extender” for the soil-gas ventilation system, with perforated pipes either passively or actively keeping radon from entering home, depending on local requirements.

LAYER 3: Gravel keeps things level under concrete-free slab

On a concrete-free slab-on grade, add a 2-in. to 3-in. 1⁄4-in.-minus gravel layer above capillary-break stone. This layer is much easier to screed level and flat so foam-insulation layers can be set in full contact without any voids or settling (this could create bouncy or uneven floors). Set a laser line on wall columns for reference and use a grading rake to get gravel close to level; checking with a tape measure. After this use a 2×4 as a screed, working it back and forth to set the grade perfectly flat, with top even with pressure preservative treated splash plank bottom.

LAYER 4: Rigid foam eliminates cold feet

Run rigid insulation horizontally under the entire slab. It’s not very costly to do in comparison to usual approaches, and barndominium owner benefits are significant. First is comfort. People don’t want to feel cold underfoot, and they tend to complain if they do. An insulation full layer under the slab mitigates this problem significantly. Just as importantly, there is a big benefit in energy efficiency. For a floating plywood slab, this continuous insulation layer is essential, providing a flat, stable surface for floating T&G plywood floating raft. Use two layers of one inch thick EPS foamboard, oriented perpendicular to one another with seams offset to ensure minimal air gaps.

LAYER 5: 10-mil poly blocks moisture migration through concrete-free slab

Fifth layer—above insulation and directly below slab itself, is a polyethylene sheet acting as a Class 1 vapor barrier. This vapor barrier isolates concrete-free slab from ground and water and vapor it contains. Climate regardless, ground relative humidity always approaches 100%. If this layer were omitted, concrete or plywood would draw moisture into the building, inviting rot, mold, and humidity issues.

Using a 10-mil polyethylene sheet is a big reason concrete-free slabs are a durable, long-term approach. It’s critical to use compatible tapes for sealing seams and to ensure complete adhesion. Any penetrations, such as plumbing or radon vents, must be taped completely from pipe to poly without gaps, folds, or other sloppy work. Fill gaps around plumbing penetrations with canned spray foam, and tape those areas carefully

LAYER 6: Two plywood layers is last step to finish concrete-free slab before interior walls go up

Sixth and final layer, resting on vapor barrier, is material creating this concrete-free slab. Plywood is standard 3⁄4-in. T&G CDX subfloor material. Pressure-treated plywood is not only unnecessary but would add chemicals and VOCs to the interior environment. Install two layers, with the second set perpendicular to the first and joints offset.

Leave a 1⁄2-in. gap between outside edges and perimeter EPS insulation or splash plank to allow T&G plywood to expand and contract. These two layers are allowed to float on layers below and are joined together with construction adhesive and 1-1⁄4-in. screws, sized so they don’t penetrate the vapor barrier below.

This entry was posted in Insulation, Pole Barn Design, Pole Building How To Guides, Pole Barn Planning, Pole Barn Structure, Pole Barn Homes, Post Frame Home, Barndominium and tagged slab on grade foundation, thermal performance, crawlspaces, embodied carbon, greenhouse gas, vapor barrier, plywood slab, Concrete, decoupling membrane, greenhouse gas emissions on March 10, 2022 by admin.

When Friends Buy Buildings From Others

When Friends Buy Buildings From Others

Long ago, in a galaxy far away……well actually it is in our galaxy.

Jeff and I met roughly 40 years ago, when his mother and my father dated. About 15 years later, I was Jeff’s sponsor when he became a member of Spokane Valley Rotary. In recent years, Jeff invested in a pole building and I was unaware of it until now – when he reached out to me with a challenge.

Jeff writes:

“Hey Mike! I have read the blog a lot and tried my best to understand the insulation issue that seems to get asked of you the most, but I’m just a little slow on understanding. Attached are three pictures of my pole building ceiling that I want to begin insulating. It is 36′ x 40′ with 14′ eaves on a 5×12 pitch. As you can see there is OSB under the steel roofing. The sides are steel from the top down to 4′ where there is OSB and hardiplank siding. Concrete floor. You can see some mold stains from the first year that I did not have a floor poured yet. For the walls I figure I can just use faced fiberglass batt rolled insulation without a vapor barrier then finish with drywall. Not sure about the ceiling. Can I just use rolled insulation? Then drywall or OSB over that? Vapor barrier? Do I need to have the 1″ = 2″ ventilation space between the OSB and the fiberglass? Only one side has the vent opening to the eave, the other side has an open lean-to. Thanks.”

Mike the Pole Barn Guru writes:

If your intent is to insulate between roof purlins with batts, Code requires a minimum one inch air space between insulation and roof deck (in your case OSB) continuous from eave to ridge. There is no way for you to accomplish this, as your building’s purlins block any possible airflow route. Your choice for insulating with a roof plane really comes down to closed cell spray foam. Other issues could be what sort of a dead load your roof system is engineered for. Typically post frame roof trusses are designed for only a five pounds per square foot (psf) top chord dead load with OSB. This would not be adequate to attach OSB, plywood or sheetrock directly to the underside of purlins. Even if trusses have adequate load capacity, your roof purlins appear to be 2×6 and would overly deflect with sheetrock applied – resulting in popped screws and failed taped joints.

In an ideal world, your roof trusses would have been designed for a 10 psf bottom chord dead load. This would be adequate to support a sheetrock ceiling and fiberglass insulation could be blown in on top of it. If this route is taken, you would need to provide adequate ventilation.

A solution could be to reach out to whomever manufactured your building’s roof trusses and inquire about an engineered repair to increase loading. These repair drawings are usually relatively affordable, however repairs often entail a fair amount of time, effort and materials.

As you have no Weather Resistant Barrier (Tyvek or similar) between wall framing and siding, I would recommend using unfaced rock wool or mineral wool batts as they are unaffected by moisture (unlike fiberglass) with a well-sealed 6mil clear visqueen vapor barrier on inside, then your drywall.

This entry was posted in Trusses, Ventilation, Insulation, Concrete, Pole Barn Questions, Alternate Siding, Pole Barn Structure, Steel Roofing & Siding and tagged fiberglass insulation, concrete floor, Ventilation, osb under roof steel, vapor barrier, top chord dead load, hardiplank siding, steel roofing on February 24, 2022 by admin.

Insulating an Existing Pole Barn

Insulating an Existing Pole Barn When Things Started Wrong

Reader TOM writes:

“Mike, I have an existing pole barn (6×6 post with 2’ on center girts ) that has a 4” concrete floor with 10 mil plastic under it. The side walls have 1” XPS insulation on the outside of girt then steel siding with no wrap or barrier. My thought is put Tyvek on inside of girt ( facing same direction as if on outside application ) then put inch and a half XPS DOW insulation against that ( because there’s two bunks already there) then 2×4 frame with batten insulation between them, then 6mil or heavier vapor barrier then OSB. The floor has PEX tubing in it but not hooked up. Is this a proper install? Also I will have to have an engineer check the BCDL as I want to put OSB on the ceiling but would like to know how to insulate the ceiling. There is a one foot fully vented overhang with a ridge vent also. Thank You for the info in advance.

Mike the Pole Barn Guru advises:

I am concerned about your building having an inch of XPS insulation between girts and siding. This allows screw shanks to flex, potentially creating slotting under screw heads and excessive deformation can result in your building cladding’s shear strength being compromised and (under extreme circumstances) racking enough to create a failure. I would feel much more comfortable if you were to add 7/16″ OSB or 1/2″ CDX plywood to the inside of girts in bays on each side of corner columns from splash plank to eave girt.

Moving forward….

Your external XPS is now acting as a vapor barrier (or close to it). Any exposed to inside seams should be taped. Do not put Tyvek on the inside of the girts, as this would allow any moisture in assembly to be trapped between it and XPS. Unless you already own a pile of 1-1/2″ Dow insulation, skip it and instead fill the balance of the wall cavity with rock wool or stone wool unfaced batts. Do not place a vapor barrier on the inside or seal OSB on the inside of the wall. Walls will now ‘dry’ to inside.

Provided your trusses are capable of supporting a ceiling, blow in fiberglass above your ceiling finish of choice. Make sure to allow at least an inch of air space above insulation at eaves so you get proper air intake from vented soffits. Unless you are very close to Canada and have at least 8000 heating degree days, do not add a vapor barrier at ceiling level.

This entry was posted in Pole Barn Questions, Building Overhangs, Pole Building How To Guides, Pole Barn Structure, Insulation and tagged rigid board XPS insulation, building racking, XPS insulation, building cladding, vapor barrier, eave girt, splash plank, tyvek, ridge vent, bottom chord dead load, OSB, CDX plywood on February 22, 2022 by admin.

Being a Fan Fan

Being a Fan Fan

Reader TOM in MACOMB writes:

“Hello, I have a 24 x 40 pole barn built last summer. It has a base layer of 10” of sand and 4’ of crushed concrete on top. This sat exposed for several months until the building was erected,it was a wet summer. The building was finished in August and has a thin vapor barrier under the metal roof. As soon as the nights started turning cool moisture started dripping from the ceiling, especially from the 3 crystal panels. This building does have a gutter with good drainage. The moisture is coming from the ground as any plastic set on the ground overnight will result in heavy condensation underneath. So with that said I am hoping this issue is simply leftover moisture that will eventually dry up in time. However mold is developing and things are rusting. I would like to speed up or help the moisture leave the building. It does have soffit vents and ridge vent. Finally to my question. Can I put in an exhaust fan or a giant ceiling fan or both to help this process? I wasn’t sure which may be better, power vent on the roof or in the gable would be better. Or perhaps a 96” ceiling fan would be enough to push air through the ridge vent. Although the vent is covered with snow in the winter as this is in northern Michigan. Thanks in advance for any advice.”

Mike the Pole Barn Guru

My educated guess is your building’s concrete slab on grade does not have a well sealed vapor barrier underneath. If this is indeed true, you need to start by removal (or minimization) of your moisture source – put a good sealant on your slab’s surface. There are other things to be done once ground thaws, we will get to them in a moment.

A powered gable exhaust fan will help to get moist air out from inside your building. Whether your proposed exhaust fan will be adequate or not will be dependent upon its CFM (cubic feet per minute) capabilities. You will probably want to plan for around 10 air exchanges per hour. If you have a 14 foot high ceiling, then 24 x 40 x 14 = 13,440 cubic feet (plus area above eave height at 4/12 slope is another 1920 cubic feet) X 10 times / 60 minutes per hour = 2560 CFM.

Come Spring – grade away from your building at least 10 feet at a 5% or greater slope. Make sure all downspouts discharge outside of this graded area. You may find it necessary to install a French Drain around your building’s perimeter in order to keep groundwater from running under your building.

This entry was posted in Ventilation, Concrete, Building Drainage, Building Interior, Pole Barn Questions, Building Overhangs, Constructing a Pole Building, Pole Building How To Guides and tagged condensation, Concrete, ridge vent, soffit vents, exhaust fan, vapor barrier on January 27, 2022 by admin.

Engineer Andy Ponders Insulation and Condensation

Engineer Andy Ponders Insulation and Condensation

Loyal (and prolific) blog reader ANDY in OXFORD writes:

“First, THANK YOU for providing so much valuable information in your blog, free of charge. I’m an engineer, quite handy, with construction experience. But everything I know about post frame construction, I learned from you. I’ve been planning for over a year, and I’ve read your first 1700 or so blogs. I’m about to place an order with Catherine Suarez, (she’s been very patient, by the way) for a 30x36x11. 6/12 roof with vented soffits and ridge, gable overhangs, and dripstop on roof steel. Location is north Mississippi, 30’s in winter, 90’s in summer with 60% to 80% humidity any time of year. It will be used as a dedicated woodworking shop, heated just above ambient in winter (except when I’m working there) and cooled only when I’m out there (rarely) in summer. I know you must get tired of insulation/condensation questions because you get so many of them. But it’s not something that’s intuitive to most of us. It’s the thing I’m least confident about. And I HATE rusty cast iron. I plan to install plywood or OSB ceiling with blown insulation above. House wrap between wall steel and girts (I would have never thought of house wrap), and craft-backed insulation between the commercial girts. Oh yes, and a good vapor barrier under the slab. So my question is . . . is this sufficient? What would Mike do??Thanks again for what you do.”

Mike the Pole Barn Guru writes:
Thank you very much for your kind words, they are greatly appreciated. If I ever have to give a technical presentation on post-frame buildings, can I recruit you for my front row?

Post frame construction appears so simple at first glance, yet is highly technical and (like most things) it is in the details where they either work as expected or fall flat (literally). A set of calculations for even a simple rectangle can easily run over a hundred pages in verifying every member and connection!

Catherine is a dream. I love her clients as they know exactly what they are investing in and it makes for an extremely smooth process for all involved.

For some reason insulation and humidity are crucial areas seemingly left as an afterthought in far too many builds, often when it is too late to make economically sound corrections.

Lafayette County, Mississippi is in Climate Zone 3A (for reference). If you were building for a residence, 2021’s IECC (International Energy Conservation Code) would have R-49 ceilings, R-20 walls and R-10 slab perimeter insulation down two feet.

What would I do?

Even though you are probably not doing radiant in-floor heat, I would lay R-10 EPS insulation sheets on top of a well sealed under slab vapor barrier. If not, when it is 90 degrees F. and 80% humidity, the dew point is 83 degrees F. Your soil temperature could well be less than 70 degrees F., meaning you will have a damp floor from condensation.

For walls, a Weather Resistant Barrier and bookshelf girts are both winners in my book! I have become a proponent of rock/stone/mineral wool unfaced batts as they remain unaffected by moisture (and humidity) with a well-sealed 6mil clear poly vapor barrier inside. You have probably read this article: https://www.hansenpolebuildings.com/2013/03/roxul-insulation/

Ceiling – I do still like blown in fiberglass for value vs. return. I would specify 18 inch energy heel trusses to allow for full thickness of R-49 insulation from wall-to-wall, in conjunction with vented eaves and ridge.

You will want to make certain you order a well insulated and wind-rated overhead door for your woodworking shop. Keep in mind, door manufacturers do tend to stretch reality with their insulation claims https://www.hansenpolebuildings.com/2017/02/high-r-value-overhead-doors/.

This entry was posted in Ventilation, Insulation, Pole Barn Questions, Pole Barn Planning and tagged house wrap, IECC, craft backed insulation, EPS Insulation sheets, insulation, vapor barrier, condensation, commercial girts on January 13, 2022 by admin.

Help! My Barndominium Roof is Dripping!

Help! My Barndominium Roof Is Dripping!

Reader TIMM in WHITEFISH writes:

“Thanks for taking my question. I recently built a barndominium in NW Montana. I tried to find someone to build it for me, but the demand and cost in the area had gone up so much that I had to do almost all the work on my own. I was not completely unfamiliar with building but not an expert by any means but I was able to get it built with helpful videos found online. I finished the home in late October and have moved in. The home is 28’x36′ with 10′ walls and is all living space, no garage. I had planned on doing spray foam insulation around the entire shell of the barn and had hired a company in August to come out and spray the barn but they were not going to be able to get to the building until December at the earliest but we were willing to do it and fight through the winter in our camper. Our plumber mentioned a product to us that he had seen some other clients use called Prodex that had similar characteristics of spray foam with a reflective surface on both sides and it was something I could do myself and much sooner. I did some research and the product looked good and the reviews looked good so I bought some and installed it. The steel was already on when I installed it so the Prodex was installed by stapling or screwing to the Purlins/Girts around the whole building which was an install method on their website. While we were mudding/painting/texturing I noticed some condensation in the attic in between the steel and the Prodex insulation (I could see where it was coming through a seam in the Prodex). I asked some people and they thought it was just because I was putting a lot of moisture in the air that was causing the condensation and it would dry out when we were done. On a recent trip up to the attic I noticed that the steel is still condensating when it is cold outside and the Prodex itself seems to be condensating as well. I emailed Prodex and they told me that it is caused by cold air moving across the inside surface of the steel and I should put foam around the ridge cap, eave edge of roof and tops of wall. I have foam around the ridge cap, but nothing on the ridge cap ends, I have foam on the eave edge of the roof, but only in the high ridge parts, and I have nothing on the walls. I am also concerned that this is happening inside of the walls which may lead to a bad mold problem next summer. My question is, how do I get it to stop condensating? I am ready to do whatever I need to do. I just don’t want to throw ideas at the house until something works. As far as ventilation goes, I am sure I do not have enough but was hoping to address that in the summer months. I do not have eaves on the building which I regret so my only real ventilation is the ridge cap and the little bit that may be coming through the ridges on the eave edge of the roof. I thought about gable vents, but I felt like that would let too much cold air in and would make the issue worse, but maybe that is what I need? If I put in gable vents, do I pull out the Prodex insulation and leave bare metal on the inside of the attic? I am trying to figure out a way to reduce the moisture right away (dehumidifier?) while I work on a long term solution but I don’t know which direction to go to solve this issue. I thought about pulling off the steel and putting in plywood sheeting, but we are in the middle of winter and that would have to wait until Spring at least and I am afraid I will end up with too much water damage by then. I have even considered putting sheeting under the roof and replacing the outside walls with wood siding but the cost would be high and I feel like there should be a solution to this issue. For heat we electric wall heaters (Cadet in-set wall units) occasionally and a pellet stove most of the time. We put the Prodex insulation as well as blown insulation in the attic to about 12 inches deep and we put Prodex as well as rolled insulation in the walls for a total of about an R30 value. Dryer and bathroom vents both go outside and nothing is venting into the attic. Any help would be appreciated! Thanks.”

Mike the Pole Barn Guru says:

Kudos to you for doing a D-I-Y. Sadly you were lead to a product (Prodex) claiming to be insulation, however in reality it is a condensation control, and only if totally sealed.

All of these issues could have been easily addressed at time of construction had your building kit provider given you proper advice.

First thing to do is to get your attic properly ventilated – you need to add at least 121 square inches of NFVA (Net Free Ventilating Area) to each gable end. This will give you an air intake and your vented ridge will then function as a proper exhaust. By itself, this should greatly minimize, if not totally cure your problems.

As time allows, remove roof Prodex, have two inches of closed cell spray foam applied to roof steel underside, and increase thickness of blown in attic insulation to R-60.

If you do not have a well-sealed vapor barrier under your concrete floor, if possible, seal top side of it (this is where moisture is coming from).

Heating as much as possible with your pellet stove will also help to dry your interior air out and provided your slab is sealed, should help greatly.

I do have some concerns about your walls, if you have faced insulation batts with Prodex on outside of batts, you are potentially trapping moisture between two vapor barriers. If this is indeed your case, come Spring, remove siding (one wall at a time) , remove Prodex (as much as possible) and add a Weather Resistant Barrier (Tyvek or similar) to the exterior of framing, properly seal all wall openings and reinstall wall steel.

This entry was posted in Ventilation, Insulation, Pole Barn Heating, Pole Barn Questions, Roofing Materials, Barndominium and tagged vapor barrier, barndominiums, condensation, net free ventilation area, eaves, girts, NFVA, purlins, gable vents, Prodex, spray foam insulation, Ridge cap on December 16, 2021 by admin.

A Basement Foundation, Vapor Barrier for Arena, and a Hansen Kit

This Wednesday the Pole Barn Guru answers reader questions about building a post frame building on a basement foundation, insulation vs a reflective radiant barrier, and a question about what is include in a Hansen Building kit.

DEAR POLE BARN GURU: Is it possible to erect one of the pole barn kits on a basement foundation? LUCAS in LANDISBURG

DEAR LUCAS: Absolutely – if you are planning a poured concrete, concrete block or ICF foundation, you will want us to provide wet set brackets to be placed in top of your walls when they are poured. We also offer an option of a Permanent Wood Foundation.

Here is some extended reading: https://www.hansenpolebuildings.com/2020/02/barndominium-on-a-daylight-basement/

DEAR POLE BARN GURU: Hey can you enlighten me on this product and if you are still using it in pole barn applications, I am considering a riding arena and need especially if commercial a vapor barrier and some added R-Value I am looking at the R-22 product.

Thanks,

Any information would be helpful Insulation4less.com doesn’t seem to have a phone number and very difficult to contact.

Saw Your Page:
https://www.hansenpolebuildings.com/tag/prodex/

ROBERT in ROCHESTER

DEAR ROBERT: Thank you for reaching out to us. If you will note, in reference to our page where you found us, Prodex is a Radiant Reflective Barrier (RRB) – it is NOT insulation, regardless of what claims might be made by any distributor of this product.

Here is some further discussion about RRBs: https://www.hansenpolebuildings.com/2014/04/reflective-insulation-wars/
In Southern Minnesota you are in Climate Zone 6. Here would be my recommendations:

Roof – order roof steel with an Integral Condensation Control (Condenstop or Dripstop) factory applied. Install a steel ceiling across truss bottom chords, blow fiberglass insulation in above steel ceiling. Vent attic at eaves with enclosed vented soffits and ridge.

Walls – use a Weather Resistant Barrier (aka Housewrap) between framing and wall steel. Place bookshelf wall girts two foot on center and fill wall cavity with rockwool batt insulation and an interior vapor barrier.
One of our Building Designers will reach out to you to further discuss your riding arena needs.

DEAR POLE BARN GURU: What is all included in a pole barn home kit?

AMANDA in HAVRE

DEAR AMANDA: Thank you for your interest in a new Hansen Pole Building. These would be included items:

Fully engineered plans including:
Layout of all columns
Roof framing plan showing all trusses, rafters and purlins
Section view(s) through building
Elevations of all exterior walls showing all wall girts, window(s) and door(s) framing
Roofing and siding layouts
Connection details of all members
Any framing layouts for raised wood floors (either over crawl spaces or for 2nd or 3rd floors
Stair details

Verifying calculations from the engineer

Construction (assembly) Manual – over 500 pages of step-by-step instructions, fully illustrated

Unlimited FREE Technical Support

Fully itemized Material List

All Materials necessary to assemble structural portions of your building, including doors and windows, with the exception of concrete, rebar and any nails normally driven by a nail gun.

This entry was posted in Pole Barn Design, Professional Engineer, Roofing Materials, Horse Riding Arena, Pole Barn Planning, Pole Barn Heating, Ventilation, Concrete, Lumber, Footings, Pole Barn Questions and tagged insulation, engineer sealed plans, vapor barrier, reflective radiant barrier, sealed plans, materials kit, wet set brackets, post frame basement, basement foundation on December 15, 2021 by admin.

Insulated Ceiling Vapor Barrier

Should a Vapor Barrier Be Installed in an Insulated Ceiling?

Should you put a vapor barrier in an insulated ceiling or not? I build in a cold climate, where many longtime builders swear that you shouldn’t put a ceiling vapor barrier in. The reasons go something like, “Because you have to let the moisture escape,” or “Because the house has to breathe out the top.” What do the experts say?

Here I will defer to Joe Lstiburek – building scientist and the founding principal of Building Science Corporation:

Mike the Pole Barn Guru says:

To heck with the experts — here’s my answer. Plastic vapor barriers should only be installed in vented attics in climates with more than 8,000 heating degree days. You can forego the plastic and use a vapor retarder (kraft-faced insulation or latex ceiling paint) in all other climates except hot-humid or hot-dry climates. In hot-humid climates, attics should not be vented and vapor retarders should not be installed on the interior of assemblies.

In hot-dry climates a vapor retarder should also not be installed, but attics can be vented. All attics — vented or unvented — should have an air barrier (a properly detailed airtight drywall ceiling, for example) regardless of climate.

Omitting a ceiling vapor barrier by arguing that “you have to let the moisture escape” or “because the house has to breathe out the top” is actually correct, in a way. It’s also incorrect, in a way. Now, I’m a real fan (ha, ha) of controlled mechanical ventilation to limit interior moisture levels in cold and mixed climates, as well as to limit other interior contaminants in all climates. In other words, all houses require controlled mechanical ventilation in order to “breathe.” It is also my view that this necessary air change should not happen because of a leaky attic ceiling, attic vents, or even leaky walls. Hence the requirement for an air barrier and controlled mechanical ventilation in all houses regardless of climate.

Having said that, I do not have a problem with relieving some of the moisture load in the house via diffusion. This can be achieved through a roof assembly designed to handle it, such as a vented attic in a moderately cold or mixed climate. It’s important to understand that this is a climate-specific recommendation. In a well insulated attic in a very cold climate (more than 8,000 heating degree days), there is not enough heat loss into an attic from the house to allow for much moisture removal through ventilation. That’s because attic ventilation requires heat loss to remove moisture from attics. Cold air can’t hold much moisture. So ventilating a heavily insulated attic with outside air when it is really cold does not remove moisture. We do not want any moisture to get into an attic in a severely cold climate for this reason. As you move south into regions where it is not so miserably cold, this changes: Hence, the recommendation for a vapor barrier in a severely cold climate but only a vapor retarder in most other locations.

In the old days in severely cold climates, where attics were poorly insulated, it was okay to omit a plastic ceiling vapor barrier. The heat loss from the house warmed the attic sufficiently to allow attic ventilation to remove moisture from the attic. Cold outside air was brought into the attic and warmed up by the escaping heat loss, giving this air the capacity to pick up moisture from the attic and carry it to the exterior. This worked well until we added large quantities of attic insulation. With the added insulation, the attic stayed cold and so did the ventilating air from outside, which was now unable to effectively remove attic moisture. Hence the need to reduce moisture flow into the attic and the need for a vapor barrier.

There’s one other important qualification: Vapor moves in two ways, by diffusion through materials, and by air leakage through gaps and holes in building assemblies. Between the two, air leakage moves far more moisture than vapor diffusion. A vapor barrier in an attic assembly in a severely cold climate with the absence of an air barrier will likely be ineffective. On the other hand, an air barrier (a properly detailed air-tight drywall ceiling, for example) in the absence of a vapor barrier can be effective, since it stops the flow of vapor-laden air. You can’t just install plastic in a ceiling and assume it is also an air barrier. For plastic to be an air barrier, it needs to be continuous, meaning all joints and penetrations must be taped or caulked.

This entry was posted in Ventilation, Insulation, Pole Barn Questions, Pole Barn Planning, Pole Barn Structure and tagged attic insulation, attic ventilation, Air barrier, air leakage, vapor retarder, Joe Lstiburek, mechanical ventilation, vapor diffusion, vapor barrier on November 2, 2021 by admin.

How Do I Ventilate My Barn’s Attic?

How Do I Ventilate My Barn’s Attic?

Right up there with curing condensation issues is how to properly ventilate a pole barn’s dead attic space.

Reader CURTIS in TRENTON writes:

“I have a 40’x60’ outbuilding that doesn’t have soffit vents for fresh air intake and the ridge cap has solid foam closures along the length of both sides of it so I have no air exhaust either. Basically just whatever air leaks are within the building. My plan is to fully finish the inside of my building. (Insulated walls and OSB sheathing and a metal ceiling with a blown in r-38) I plan on making it as air tight as possible. This building will be heated some over the winter as well. My roof panels also have the “drip X” felt like material that is attached to the underside of the panels. I believe this acts as a vapor barrier to keep the roof from condensing. My question is since I don’t have soffit vents or a vented ridge cap do you recommend adding 2 gable vents? If so, what size? I know there’s a formula for sizing them. I believe it is the square footage of the building, (40×60=2400/300=8 sq ft) so would be adding a 4 sq ft gable vent on each end of the building be sufficient? 4 sq ft of intake and 4 sq ft of exhaust totaling 8 sq ft of ventilation? Or should I do a gable vent on the west side of my building for air intake and a shutter exhaust fan wired to a humidistat/thermostat on the east side (away from prevailing winds) to pull hot air from the attic. I believe there’s a formula for this too to determine the fan’s cfm rating and the gable vent size. (40×60=2400×0.7=1680CFM)

Add an additional 15% (1680×1.15=1980CFM) for a darker colored roof. My roof is forest green. So an exhaust fan with a minimum rating of 1980CFM/300=6.44 sq ft, which would determine the gable vent size on the west end of the building. Examples: 30”x32”=6.65 sq ft or 26”x36”=6.48 sq ft) My question is are these formulas correct and which one do you recommend using? Two gable vents, a gable vent and a shutter exhaust fan, something different or nothing at all? I just want to do this right and make sure my attic has sufficient ventilation once it’s enclosed. I hope to hear back from you. Thanks!

Last questions. I found a 36×36 square gable vent that has a NFVA of 585. I need 576 on both sides of my building so this vent should be sufficient, correct? Also, with me using the 1/300 ventilation rule the gable vent company who has this vent recommended using a vapor barrier in the attic too. I believe he said that it needs to be no more than 1 perm and to install it on the warm side of the attic. He said this is needed because I’m not using the 1/150 rule. He said if I have 16 sq ft on ventilation instead of 8 I wouldn’t need a vapor barrier. That’s not really an option though. That many gable vents wouldn’t look good. So what do you think? Do I really need a vapor barrier using the 1/300 rule? My roof panels have a felt-like material on the underside of them that I believe is called “drip x”. I was under the impression that this was a vapor barrier and when warm air rises and hits those cold roof panels the “drip x” keeps it from condensing. Do I really need a vapor barrier along the warm side of the attic too? That sounds like overkill to me but I want to do it right too. The plan is to fully finish the inside of my outbuilding eventually with a ceiling that will be white ribbed panels with a r-38 blown in fiberglass. I only plan on heating the building to about 55-60 degrees and that’s only if I’m out there working. The thermostat will be set to 45-50 if I’m not out there. Also, this outbuilding doesn’t currently have air conditioning but I may consider adding it down the road. You’ve been a big help so far. Thank you and I look forward to your response. “

Mike the Pole Barn Guru responds:

As long as your four square feet (576 square inches) of NFVA (Net Free Ventilation Area) is located in the upper half of each gable endwall, your formula is correct and should provide sufficient ventilation. Actual vent size is not the same as the NFVA – so look closely before investing in any particular vent.

A vapor barrier would only be needed if you have over 8000 heating degree days. One of those vents on each end should do the trick.

You can look up your heating degree days here: https://www.huduser.gov/portal/resources/UtilityModel/hdd.html

This entry was posted in Pole Barn Heating, Pole Barn Planning, Ventilation and tagged Ridge cap, exhaust fan, air intake, air exhaust, vapor barrier, condensation, Ventilation, gable vents on October 29, 2021 by admin.

How to Pour a Slab on Grade

How to Pour a Slab on Grade in an Existing Barndominium

Reader PAUL writes:

“I have an opportunity to purchase a barndominium that has the posts set in 20” wide 40” deep peers. Unfortunately the county where this is located does not require a footing. All city codes in this area require an 8”X 36” footing. What solutions do you recommend for pouring the slab now that the shell has been erected?”

Most post frame buildings have shells erected then slab poured, so this should not be an issue. A pressure preservative treated splash plank should be in place around this building’s perimeter. It will become forms for your slab. Snap a chalk line on the inside of splash planks up 3-1/2″ from bottom, this will be top of your slab.

In Climate Zones other than 1 through 3, you will need to frost protect the building perimeter. This can be done by trenching around the edge of the building to required depth – 24″ in zones 4 and 5, 48″ in 6 and greater. It is usually easiest to install R-10 rigid insulation on the inside of the splash plank, with top of insulation even with top of slab to be poured. This also precludes any need to UV protect vertical insulation.

Depending upon how the site was prepared, you may need to excavate inside of this building.

If in “frost country” a sub-base 6” or thicker should be first placed across the site. To maintain frost-free soils sub-base should be such as no more than 5% (by weight) will pass through a No. 200 sieve, and it is further desired no more than 2% be finer than .02 mm.

Prior to pouring, 2” to 6” of clean and drained sand or sandy gravel is spread below where concrete is to be poured. Mechanically compact fill to at least 90% of a Modified Proctor Density, otherwise slab could sink.

In areas prone to subterranean termites treat prepared soil with a termiticide barrier at a rate of one gallon of chemical solution per every 10 square feet.

Install a good, well-sealed 15mil vapor barrier below any interior pour, to stop moisture from traveling up into the slab through capillary action. Overlap all vapor barrier seams by a minimum of six inches, then tape. Vapor barrier should extend up column sides and to splash plank top.

Minimum R-5 (R-10 being preferred) insulation shall be provided under full slab area of a heated slab in addition to required slab edge insulation R-value for slabs as indicated in International Energy Conservation Code (IECC) Table R402.1.2 Footnote (d).

In most instances, over properly compacted fill, 15 psi (pounds per square inch) EPS (expanded polystyrene) or XPS (extruded polystyrene) insulation has adequate compressive strength to support a five yard dump truck on a nominal four inch slab on grade.

Consider this: 15 psi equals 2160 psf (pounds per square foot), making this greater than assumed compressive strength of most soil types.

If not using fiber-mesh or similar reinforcement additives to concrete mixture, place rebar (reinforcing steel rods) in slab center to add rigidity to concrete to aid in minimizing cracking.

This entry was posted in Pole Building How To Guides, Shouse, Pole Barn Planning, Concrete, Post Frame Home, Insulation, Barndominium, Pole Barn Questions and tagged International Energy Conservation Code, vapor barrier, Climate Zones, splash plank, R-10 rigid insulation, concrete slab, No. 200 sieve, barndominium, Modified Proctor Density, termiticide on September 29, 2021 by admin.

Insulating a Hybrid Building

Insulating a Hybrid Building

Reader COLTON in DAWSON writes:

“Insulation question? I am going with a Worldwide Steel Building. Identical to a Perka. Part of it will be shop and part will be house. It’s a steel web truss with wood purlins and girts. I’m stuck on a lot of guys say just put house wrap on the entire outside or a foil. And batt/roll in the 2’ purlin and girt spacing. And some want to use metal building insulation and roll it on top. I’m not sold on the squashing it in between the tin and possibly causing issues there. I would rather house wrap it and fill in between the purlins and girts with unfaced fiberglass then add a clear vapor barrier inside and then install tin inside the shop and drywall inside the house. Just want your honest opinion since you lived and learned. I enjoy all your helpful information. Thanks!”

My grandson Colton just turned 10 yesterday!

Thank you for your kind words.

You are now faced with what can be a perplexing challenge with a steel framework/wood girts and purlins hybrid building – how to best insulate.

For walls – siding, weather resistant barrier (aka house wrap), unfaced batts, clear poly, interior finish works fine. On your roof, house wrap allows moisture to pass through and be trapped between it and roof steel – possibly causing premature degradation of your roofing. You need a thermal break directly below roof steel. I would recommend an Integral Condensation Control (https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/). If this is not an available option, then a Reflective Radiant Barrier with well-sealed seams will work (we have it in six foot wide rolls with a tab on one side having an adhesive pull strip). Metal Building Insulation can be an effective condensation control under roof steel (provided seams are sealed), however it is difficult to work with, provides limited actual insulation value and can cause your roof steel to pucker. Code requires ventilation from eave-to-ridge above batt insulation between purlins, and there is just no practical way to do it. Instead, place ceiling joists between bottom chords of steel frames and blow in fiberglass insulation. Vent dead attic space above insulation (ideally at eaves as an intake, ridge as an exhaust).

This entry was posted in Pole Barn Questions, Pole Barn Design, Insulation and tagged insulation, vapor barrier, metal building insulation, batt insulation, house wrap, unfaced fiberglass insulation on August 25, 2021 by admin.

Home Addition, Combo Building, and Moisture Barriers

This week the PBG answers reader questions about a post frame addition to a house, a combo business/residential building, and use of a vapor barrier.

DEAR POLE BARN GURU: We bought an older ranch house with a poorly done addition in the back. Since this dream property came with a house that prevents me building my dream barndominium, what are your thoughts on replacing this addition with a post beam constructed addition? if we pour a slab for the floor there would be about 2 or 3 steps down to the new room. it would allow for ground level indoor/ outdoor living, higher ceilings than the rest of the ranch, and give me just a bit of the open living space with exposed trusses that I’ve dreamed of. Carolyn

DEAR CAROLYN: Fully engineered post frame additions work well with pretty much any existing structural system. You also are not obligated to use steel roofing and siding, so it can be designed to match with your home. Another advantage is – you can do this sort of work yourselves, without having to hire it done!

DEAR POLE BARN GURU: Combination business and residential? Square footage of 7000. Can it be done? KEVIN in FLORISSANT

DEAR KEVIN: Interesting timing, as I was just going through some old family photos this week and found one of my grandfather in their grocery store from the 1930’s. My mother and grandparents lived upstairs from this store.

As for modern day combination business and residential, it can certainly be done using a fully engineered post frame building. Depending upon use classification of your business, it is likely you will be required to have at least a one hour fire separation between these dissimilar uses (really not any major thing – just a consideration).

DEAR POLE BARN GURU: Hello, I have a 24x50x8 pole building, concrete floor, and all metal is screwed directly to the wood framing. The purlins are spaced 2′ OC between the trusses, and I have 3.5″ closed cell rigid foam board to install between the 2×4 purlins. For the walls I have 1.5″ closed cell rigid board to install between the girts.

On the underside of the purlins after the closed cell rigid insulation is installed, I intend to install metal panels from the ridge to the walls. So, outside to inside it will be the following: Roof metal, then 2×4 purlins with 3.5″ rigid closed cell foam board in between, then metal panels installed on the interior. I will not have anything on the bottom chord of the trusses.

On the walls I plan to cut-to-fit the 1.5″ closed cell rigid foam board and install between the girts. After foam board is installed I intend to line all interior walls with painted OSB.

Question: based on the above, can I use vapor barrier (or plastic) between the interior metal and the 3.5″ foam board, and extend the vapor barrier down the walls between the foam board and the OSB? Or do you have another recommendation? COREY IN COULTERVILLE

DEAR COREY: You are far more ambitious than me, to cut and fit all those insulation boards to fit between purlins and girts. As it will be impossible to perfectly seal all of those joints between insulation and framing, it would be a good idea to install a well-sealed vapor barrier between insulation boards and steel liner panels. Keep in mind, you may end up with some humidity issues inside of your building (especially if there is no vapor barrier under your concrete floor), so you may need to have some sort of mechanical dehumidification.

This entry was posted in Ventilation, Building Interior, Pole Barn Homes, Insulation, Post Frame Home, Pole Barn Questions, Building Styles and Designs, Shouse, Pole Barn Planning and tagged moisture barrier, side shed, post frame addition, combo building, insulation, mixed use structure, vapor barrier on August 2, 2021 by admin.

Financing, Vapor Barrier, and Boat Storage

This Friday’s daily blog will feature three questions and answers from the Pole Barn Guru. First is a question about financing, followed by a question about a vapor barrier for an add-on lean-to, and then building a quite lengthy boat storage facility.

DEAR POLE BARN GURU: Hi there. I’m looking to utilize a VA loan for 10 acres of property in West Texas. However, as a requirement, there must be a livable structure built with electrical and AC.

It was always our intention to build a pole barn or barndominium on the property but with the requirement of having such in place to qualify, we now need to consider doing this as part of the loan process.

So, my question really is, do people typically DIY with these barn kits or do they hire to build? I believe we’ll have to hire to build but I’m not sure who to contact or what is decent pricing for a build outside of the kit. I’m making a basic assumption of a 40 x 40 kit with 12 – 15 tall ceilings and basic foundation. We would convert it as a living space with insulation and electric as well during the process. We do intend on also building two separate living areas along with it in the future and then using the larger area for Entertainment.

Any guidance would be extremely helpful. Thank you! CORY in HURST

DEAR CORY: Obviously you are finding some challenges when it comes to being able to utilize your VA benefits: https://www.hansenpolebuildings.com/2020/08/va-loans-for-a-pole-barn-residence/

I would say our barndominium clients are pretty much evenly split between those who erect their own shells and those who hire it done. In order to get your best possible appraisal value to cash outlay – DIYing as much as possible will be to your advantage. A fair price to erect your shell is usually about 50% of what your investment is into your building kit.

DEAR POLE BARN GURU: We are adding a 30×60 lean to shop area to out existing 40×60 insulated pole barn. I have been told a hundred different ways to insulate it, but my biggest concern for tomorrow is I have to make a decision. I pre built all of the walls and they are ready to go up. I am getting so much conflicting advice. We are connecting to the pole barn. (Yes it has been engineered)! Do I need to put a vapor barrier, vapor retardant, or any material against the existing outside wall that will become an inside wall? I have a crew coming over to help carry the walls and stand them up. I do have a couple of other questions, but this is the most pressing.

So my husband is really sleeping as I type this. It is midnight. He works late and has to get up early and I am up trying to research for him. When I read your story about you and your wife it reminded me of my husband and myself. We have worked on a lot of projects together.

Thank you in advance. JOLENE in WICHITA

DEAR JOLEEN: Kudos to you for having an engineered building! Just so much more prudent than not.

If your lean to and existing pole building are both conditioned then your inside wall needs no vapor barrier or retarder. Your new outside walls will need something however what it is will depend upon how you plan upon insulating.

DEAR POLE BARN GURU: I’m looking to put in a boat storage facility, it will be 30′ wide by 600′ long and 15′ tall. What do I need to look at? GREG in PERRY

DEAR GREG: Column spacing will depend upon whether you are stacking boats (https://www.hansenpolebuildings.com/2018/09/boat-storage-pole-barns/) or placing them individually in bays. For 600′ in length, you will need to have interior shearwalls running 30′ direction probably no less than every 120 feet along your length. One of our Building Designers will be reaching out to you Monday to further discuss your needs and best design.

This entry was posted in Ventilation, Columns, Sheds, Boat Storage, Pole Barn Questions, Pole Barn Design, Constructing a Pole Building and tagged pole barn financing, insulation, vapor barrier, boat storage on March 26, 2021 by admin.

Condensation Control, Mother/Daughter Addition, and Vapor Barrier for Roof

Today the Pole Barn Guru answers readers questions about condensation control in a small garage with a gravel floor, the possibility of adding a “mother-daughter” unit to her house, and “ribbed vapor barrier” for a shed roof.

DEAR POLE BARN GURU: Recently purchased a metal garage kit, 24X26. No insulation. Two garaged doors. Gravel floor with plastic under grave. I am getting condensation on some days, that makes my cars, etc have like a dew on them.

My rib looks to be 1” and 7” between ribs. How do you install a wall vent with the ribs? JODY in ALTON

DEAR JODY: First step is to take care of your source. Pour a concrete slab on grade with a well sealed 10-15mil vapor barrier underneath. As you have no thermal break between your warm moist air inside building and roof steel, have two inches of closed cell spray foam insulation applied to underside of roofing. You would be better served to vent eaves and ridge, than just gable vents. If gable vents are your choice, look for vinyl vents with a snap ring as they can be installed on ribbed steel siding.

Using inward vent base edges as a guide, mark area to be cut on endwall steel INSIDE, make hole cut square with steel sheet (vertical cut lines parallel to steel ribs). Cut hole with appropriate tools.
Push vent base through hole in steel from inside.
Note word “TOP” on base when positioning. Vents installed with top side in any direction other than up will allow water to leak into building.
While holding vent base in place, snap face into base from steel exterior by pressing firmly (this takes two people).

DEAR POLE BARN GURU: I’m interested in building an attached mother/daughter addition to my home. Do you have plans for that? Approximately 600-700sq ft. NANCY in MONROE TOWNSHIP

DEAR NANCY: Thank you for your interest in a new Hansen Pole Building. Every building we provide is custom designed to best meet the wants, needs and budget of our clients. We offer a floor plan design service for folks just like you: http://www.hansenpolebuildings.com/post-frame-floor-plans/?fbclid=IwAR2ta5IFSxrltv5eAyBVmg-JUsoPfy9hbWtP86svOTPfG1q5pGmfhA7yd5Q

DEAR POLE BARN GURU: We are having a 50×30 all metal building. We were advised to get ribbed vapor barrier for roof. We have searched everywhere. Is it called something else? SHANNON in OLEAN

DEAR SHANNON: We are also not familiar with any product known as a “ribbed vapor barrier”. We would normally recommend use of roof steel with an ICC factory attached (https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/). If this is not an option (or if you are using closed cell spray foam directly to underside of roof steel), next choice would be a radiant reflective barrier – look for six foot wide rolls with an adhesive pull strip attached for ease of installation.

This entry was posted in Pole Barn Questions, Roofing Materials, Pole Barn Planning, Post Frame Home, Ventilation, Concrete, Insulation, Pole Barn Homes and tagged drip stop, add on, vapor barrier, A1V reflective radiant barrier, condensation, A1V, mother-in-law apartment, roof condensation on March 22, 2021 by admin.

Adding Heated Space in a Pole Barn

Adding Heated Space in a Pole Barn

Reader THOM in COLRAIN writes:

“ I’m creating a 20′ X 30′ heated shop space in the center of a 40′ X 70′ pole barn. One 20′ side is on an outside wall. The other three have 2 X 4 studs. I’m using rough-cut 1″ for the walls of the heated space. The cold side of the stud wall does not need to have any sheathing, though it can, if necessary.

Where should the reflectix go? I’m comfortable with it being on the hot side of the 1″ boards. Does the heated shop count as the air gap, or should it go under the sheathing. I look forward to your response, and Happy New Year!”

Mike the Pole Barn Guru says:

Happy New Year to you as well!

I noticed your umass.edu email address, our youngest son is working on his doctorate in exercise and muscle physiology at UMass Amherst.

Reflectix® is a reflective Radiant Barrier (RRB) and not an insulation (https://www.hansenpolebuildings.com/2014/04/reflective-insulation-wars/).

Many considerations need to be made when conditioning a space.

Unless you are going to have HVAC provisions to dry the inside of your heated shop space, you want to dry your space to the exterior . As such, you should have a WRB (like Tyvek) on your shop exterior, then either unfaced batts with 6mil poly on inside, or kraft faced batts. Your ceiling insulation should be unfaced without a vapor barrier. You will probably want to have some sort of exterior sheathing or other barrier to keep rodents from nesting in your insulation. In answer to where Reflectix should go – probably not on this space you are creating.

There is yet another consideration to be made. Most cold storage post frame (pole barn) buildings with concrete slabs on grade do not have vapor barriers underneath. You can determine if yours does or does not have one by placing a wrench on your floor overnight. Next morning, when you remove this wrench, if a dark space appears on your floor where your wrench was, you do not have a vapor barrier underneath. If this is your case, a sealant should be applied on your slab to minimize moisture entering your conditioned space.

This entry was posted in Pole Barn Planning, Ventilation, Concrete, Building Interior, Insulation, Pole Barn Questions, About The Pole Barn Guru, Pole Building How To Guides and tagged vapor barrier, tyvek, reflectix, reflective radiant barrier, kraft faced batts, unfaced batts on January 6, 2021 by admin.

Decisions, Decisions – Vapor Barrier for a Post Frame Steel Reroof

Decisions, Decisions – Vapor Barrier for a Post Frame Steel Reroof

There are few reasons to replace an existing post frame building’s steel roof, as properly installed it should last a lifetime. Among these reasons could be:

Tired of Existing Color
Old roofing was nailed on
Tree fell through roof

This last one actually occurred to our shouse (shop/house) when I lived in Northeast Washington!

Loyal reader and Hansen Pole Buildings’ client MIKE in COUPEVILLE writes:

“I am currently re-siding/re-roofing an existing pole building in order to match the exterior of the building I recently purchased from you. This building is roughly 32 x34 and the roof purlins are 2×6 on end roughly every 2 feet. I’m using Fabral’s grand rib 3 29ga for the roof and it will have fully vented soffit overhangs and a vented ridge cap. I am trying to figure out what I’m going to do for at least a vapor barrier under the roof steel, I see you seem to recommend foil faced bubble insulation but that is not very common in my area. I am seeing a lot of people using lamtec wmp-vrr (fiberglass insulation with a poly backing) 3″ thick and I believe they lay these wide rolls on top of the purlins and then place the metal roofing on top of that then screw down the roofing compressing the fiberglass insulation between the metal roofing and the purlins. Have you seen this style of insulating before? Do you think it is an acceptable way of doing it? I see as killing two birds with one stone. I may be insulating this shop in the future so if I do then the roof is already insulated plus I believe it acts as a vapor barrier which is the main reason to do it as I don’t want any condensation dripping down on the inside of the shop. I live in the Seattle area if that helps to know what my climate is like. Thanks in advance for your input.”

Mike the Pole Barn Guru responds:

Our recommendation would be to order your roof steel with factory applied I.C.C. (https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/).

Metal Building Insulation (fiberglass with a vinyl facing) is a decent condensation control, provided all of the seams are tightly sealed. It is a pain to work with, provides very little effective insulation value and makes your roofing pucker outwards between purlins https://www.hansenpolebuildings.com/2011/11/metal-building-insulation-in-pole-buildings-part-i/.

If it is too late for an I.C.C. then the radiant reflective barrier (https://www.hansenpolebuildings.com/2017/05/effective-reflective-insulation/)

is probably your best option. Order in six foot width rolls to minimize seams and make sure to get a product including a tab along one edge with an adhesive pull strip attached.

This entry was posted in Insulation, Pole Barn Questions, Roofing Materials, Pole Barn Planning, Steel Roofing & Siding and tagged fiberglass insulation, metal building insulation, condensation control, I.C.C., radiant reflective barrier, soffit overhangs, reflective insulation, vapor barrier on December 30, 2020 by admin.

Nanoo Nanoo

Nanoo Nanoo

In today’s riveting episode of Pole Barn Guru blogs we are actually going to discuss nanograms, not Robin Williams’ character Mork’s salutation from a late 70’s sitcom.

Reader KEN from INDIAN RIVER didn’t plan his pole (post frame) building with a WRB (Weather Resistant Barrier like Tyvek) and now writes:

“Mr. Pole Building Guru. I installed a 30 x 56 pole building without Tyvek under metal I now want to insulate With 1.5″ foam board between purlin then insulate with unfaced fiberglass then install OSB for walls. I don’t want to create two vapor barriers which I think the foam would create one then the OSB. not quite sure how to insulate for best results any suggestions?”

Mike the Pole Barn Guru responds:

Provided you are able to completely air seal your foam boards between wall girts, they may act as an effective vapor barrier. Personally I would opt for two inches of closed cell spray foam rather than foam boards. In either case, this means you need to dry your wall to the inside.

Whether or not a material qualifies as a vapor barrier is determined by how much moisture passes through it, and it is given a rating. Any material allowing less than 60NG (nanograms) of moisture to pass through under specific conditions, is considered a type nine residential vapor barrier. A nanogram happens to be fairly small – it is one billionth of a gram!

Including a vapor control measure on your wall insulation’s warm side insulation is essential for preventing moisture movement through walls in winter, and ensuing damage coming with it. In summer however, with a combination of hot, humid days and air-conditioned, dry interiors, vapor drive reverses and can force moist air inwards through your insulation where it can condense on a cold and impermeable vapor barrier.

Ideally we’d have no vapor barrier in summer; but short of this we should at least have one allowing as much drying to interior as possible without sacrificing its winter performance. So the close your vapor barrier is to 60NG, the better. For context it should be noted polyethylene (Visqueen) is rated at 3.4NG.

Rated at 44NG (2/3rds of a perm), 7/16 inch OSB sheathing can be a reasonably good vapor barrier, however you may want to consider instead using 3/8″ CDX plywood as it has a 57 NG rating. Do not seal it (paint is a seal) or tape seams and your wall is probably okay.

P.S. You long time readers have probably been wondering how I would incorporate “Nanoo Nanoo” into an article. Well, now you know!

This entry was posted in Building Interior, Insulation, Pole Barn Design, About The Pole Barn Guru, Pole Barn Planning, Pole Barn Structure, Ventilation and tagged CDX plywood, nanogram, vapor control, insulation, vapor barrier, condensation on December 15, 2020 by admin.

11 Reasons Why Barndominium Crawl Space Encapsulation is Important

11 Reasons Why Barndominium Crawl Space Encapsulation is Important

Today’s Guest Contributor is Joseph Bryson. Joseph was born in Alberta, raised in NYC and is living in New Zealand. He has been working in 4 different industries and helped numerous businesses grow. Now, he is focused on writing as his next career from home and lives a peaceful life with his family and a whole pack of dogs.

No matter what kind of a barndominium you will have, if there is a crawl space present then it can potentially cause you a whole host of problems. People tend not to realize this because they don’t think too much about crawl spaces.

Like it’s not a place people generally venture to in their own homes. It’s just down there beneath your elevated wood floor, out of sight and out of mind. And so various issues can arise in your house you don’t know how to fix because you don’t realize they’re originating in your crawl space.

In a post-frame building, crawl spaces are set up a little bit different. Instead of having a perimeter of concrete and a concrete slab, it is instead a wooden framework on short pressure preservative treated timber or glu-laminated columns.

It’s a style of crawl space allowing for much better access to plumbing, ventilation ducts and electrical wiring, but without a concrete slab. It also makes it somewhat more susceptible to some of these problems.

This leads us to crawl space encapsulation creating an unvented crawl space. A process involving installing a vapor barrier in your crawl space to cover ground, walls and seal up all vents and seams. Air is then conditioned using a humidifier or HVAC system.

International Residential Code (IRC) R408.3 addresses unvented crawl spaces. Exposed earth is covered with a continuous Class I vapor retarder. Vapor retarder joints shall overlap at least six inches and be sealed or taped. In post frame buildings, this vapor retarder must extend up perimeter walls to floor level and be attached and sealed to floor. One of four possible options outlined in IRC R408.3(2) must also be met.

Let’s have a look at what issues a crawl space encapsulation will help to prevent and why it’s so beneficial:

Controls Pests

One very important thing you’ll be doing by sealing up all openings is removing access to your crawl space for a wide variety of pests. You can get mice, rats, cockroaches, racoons and even birds have been known to find their way into crawl spaces.

Once pests find their way in, it can be a nightmare getting them out but an encapsulated crawl space removes a primary entry point for pests so you would be reducing possibilities significantly.

Roaches can be disastrous for a wooden framework and so you should be very serious about keeping them out of your crawl space and your home in general.

Improves Air Quality

Because air coming up through your crawl space will be going through HVAC or a humidifier, you can rest assured it will be much higher quality than if it was just blowing in unfiltered. A crawl space is a hot bed for low quality air, but not if it’s encapsulated.

Allows for Better Energy Efficiency

One thing you will probably notice after encapsulation is your energy bills will be lower. Your heating and air conditioning won’t have to struggle against crawl space damp air, meaning they’ll be doing less work.

And this will of course result in you having to spend less on utilities. While encapsulation might cost a bit, it is Code required and will be financially beneficial over time.

Keeps Floors Warm

As we just mentioned, the normal state for a crawl space is to be full of damp air. It’s exposed to elements and especially during winter months, this just means there’s consistent moisture and low temperatures blowing through.

All of this is prevented with encapsulation meaning the only thing rising from below will be heat. And while it won’t necessarily be equivalent to under floor heating as such, it will make floors more warm and comfortable to walk on, especially in a post-frame home where there isn’t concrete separating heat from floors.

Prevents Mold

Mold is very problematic. For some people it’s just an irritant causing things like coughing, sneezing and sore throats, but it can also be toxic if left to grow for too long. And for anyone with a compromised immune system or who suffers from asthma, it’s dangerous.

Mold and mildew are further consequences of dampness and moisture retention and most crawl spaces are full of it. It’s much more likely to build up on wood than it is on concrete meaning this is more common in wood frame structures.

Improves Storage

Not everyone opts for using their crawl space for storage, even after it’s been encapsulated, but it can be done. If your encapsulation is neat, you should definitely have some room down there to store a few boxes.

If you did this with an unencapsulated crawl space, then anything you store could be potentially damaged by moisture or mold. So it’s basically a really safe storage space once encapsulated.

Prevents Flooding

I’ll start this point by saying crawl space encapsulation doesn’t necessarily prevent floods entirely, but it can help in a lot of cases. Excess rainwater and runoff can build up down below and can result in flooding, but not if everything is sealed and blocked up.

Flooding takes a much greater toll on wood than it does concrete and although your post-frame home will be sturdy by design, too much water over time could do some serious damage.

Protects Structural Integrity

If left for long periods of time without intervention, moisture and mold will slowly eat away at untreated wood under your home. This will eventually destroy structural integrity and you won’t have any idea it’s happening because it takes so long.

Just another reason why you should be slowing down, or entirely stopping mold growth and retention of moisture.

Keeps Allergens at Bay

Spread of allergens is primarily caused by moisture and dust. We’ve discussed to death how moisture is controlled by encapsulation, but because air coming through is unfiltered, dust shouldn’t be a problem either so if you’re prone to allergies you will benefit.

Can be Done Without Professional Help

Key word here is ‘can’. Crawl space encapsulation can be done without professional help. Before hiring a professional it’s worth looking into how you would do it yourself.

If you have an interest in DIY and are particularly adept at this type of handiwork, you could for sure give this a try. Again, not everyone will be up to this task, but if you are then it will save a lot of money.

Enhances Longevity of Your Home

With all of these different things considered, it’s clear crawl space encapsulation will help make sure your barndominium is in livable condition for a long, long time. Every issue we’ve discussed here will gradually build up until it becomes potentially disastrous.

Crawl space encapsulation is a big job, but fairly easily accomplished DIY.

This entry was posted in Post Frame Home, Barndominium, Pole Barn Design, Pole Barn Planning, Ventilation and tagged allergens, HVAC, barndominium flooding, crawl spaces, crawl space encapsulation, barndominium crawl space, vapor retarder, vapor barrier, pest control, humidifier, Ventilation, mold and mildew, glu-laminated columns on November 19, 2020 by admin.

I Think I Have Made Some Errors!

If you are a post frame building kit provider or a builder reading this article – please STOP SELLING ONLY ON A CHEAP PRICE. You are leaving dissatisfied clients in your wake and doing a disservice to our industry.

Reader RICK in IDAHO writes:

“Hello Sir! I think I have made some errors when I had my PB built regarding insulation plans. 30×40 with 12’, 8” side walls on the inside. Cement floor. No Tyvek or other barriers on walls or roof, just steel on wood all around. Soffit vents all the way around and vented roof cap. Was planning to have insulation blown in walls and ceiling, with a vapor barrier (reinforced plastic?) facing interior occupied area. Did not use closure strips but used canned spray foam to insulate/seal the ribs and edges walls, top and bottom and roof. Trusses were engineered for sheet rock ceiling. Won’t have temps above 50 F in winter on occasion But will try to keep above freezing in winter. No AC in summer. South East Idaho- hot summers and some -10/20 degree nights in winter with generally low humidity year around. Edge of the Idaho desert. Any advice? Thanks for sharing your knowledge with us!”

Thank you Rick for your kind words.

I cannot fault you – an average person having a post frame (pole) building built doesn’t know what they don’t know. I see this situation occur over and over when building providers or builders do not thoroughly explain options and their benefits to clients, instead relying upon a cheap price.

If your concrete slab on grade does not have a vapor barrier under it, seal the top of your floor. https://www.hansenpolebuildings.com/2019/02/how-to-properly-apply-post-frame-concrete-sealant/

Use two inches of closed cell spray foam against your wall and roof steel – if not, you run a high risk of condensation troubles. If you are going to blow insulation into your walls, use a product such as BIBs. https://www.hansenpolebuildings.com/2011/11/bibs/
Do not use a vapor barrier inside of either your walls or ceiling. Make sure the spray foam applicator does not spray over your eave or ridge vents.

All of these things are manageable, they just could have been solved far more economically if they had been done right to begin with.

This entry was posted in Insulation, Pole Barn Questions, Constructing a Pole Building, Pole Building How To Guides, Ventilation and tagged closed cell spray foam, closed cell spray foam insulation, canned spray foam, sheet rock ceiling, eave vents, vapor barrier, BIBS insulation, ridge vents on November 13, 2020 by admin.

Air Sealing Your Post Frame Barndominium

Unless someone reincarnates Nikola Tesla (and he is sane) chances are good energy costs are not going to decrease. Air sealing your post frame barndominium or shouse increases your comfort by reducing drafts and cycle time your heating and cooling systems are running.

Air sealing your barndominium reduces humidity increasing comfort levels. A drafty barndominium is more than just a waste of natural resources, it also means higher energy bills. Air sealing will automatically lower your energy bills due to less leakage of conditioned air.

Using two inches of closed cell spray foam directly inside steel siding panels not only air seals exterior walls, as it is an effective vapor barrier, but also provides approximately a R-14 level of insulation. Effective applications also require installing form fitted inside closure strips at top and bottom of every wall steel panel – including window and door openings. Closure strips keep spray foam in your walls rather than oozing out and keeps small crawling and flying critters out.

For those who opt not to utilize closed cell spray foam, air sealing begins with a totally sealed Weather Resistant Barrier (WRB) wrapping all framing before steel siding is applied. For further reading on Weather Resistant Barriers please see: https://www.hansenpolebuildings.com/2016/01/determining-the-most-effective-building-weather-resistant-barrier-part-1/

Care should be taken to effectively use WRBs around openings for windows and doors, as well as utilizing caulking and self-adhesive sealant tape for an airtight seal. Place sill gaskets under all exterior doors. Use spray foam or caulk to fill any gaps between doors and windows and adjacent framing.

In Floor Heat System Installation When placing under slab vapor barriers, run up inside of pressure preservative treated splash planks and sealing to top and around columns. Install seal gasket under pressure treated base plate (mud sill) and caulk inside edge to concrete slab.

With wall insulation systems other than closed cell, use a clear visqueen vapor barrier on the inside of all framing. Seal every penetration in this vapor barrier.

Before installing interior window and door trims, caulk where trim will meet frames. Make sure door sweeps are installed and the threshold is properly adjusted.

Common infiltration paths include attic access and simply insulating envelope (or shell) isn’t enough. In fact, insulation’s ability to perform is almost cut in “half” if not air sealed first.

Expandable polyurethane is used in areas too wide for caulk. If an area is wider than 1/4″ caulk can fall out of grooves. Acrylic-latex caulk is for all gaps small enough for caulk to function properly such as base plate and seam between floor and wall and wall and ceiling. Fire-rated caulk is non-combustible and for any areas where wires penetrate through base plates, walls, etc. (This is a recently implemented new national code.)

While it seems obvious gaps and crevices in a barndominium should be sealed, most builders either have not yet begun or just recently started utilizing air sealing processes. If hiring a contractor, make certain complete air sealing processes are spelled out in contractual documents – money you will save over your barndominium’s lifespan.

This entry was posted in Post Frame Home, Insulation, Barndominium, Pole Barn Design, Shouse, Pole Building How To Guides, Pole Barn Planning, Steel Roofing & Siding, Pole Barn Homes and tagged R-14 insulation, weather resistant barrier, self-adhesive sealant tape, sill gaskets, closed cell spray foam, closed cell spray foam insulation, f, WRB, vapor barrier, inside closure strips, air sealing on October 27, 2020 by admin.

Span, Vapor Barriers, and Planning a Pole Barn

This week the Pole Barn Guru answers reader questions about the widest span a post frame building can be built, vapor barrier on a roof only structure, and the proper steps for planning a pole barn.

DEAR POLE BARN GURU: How wide can you span? And approx cost per sq ft for an erected shell, (no floor Hvac or electric. 100’x110′ bldg.. JOHN in LEWES

Arena Interior

DEAR JOHN: While we have quoted fully engineered post frame buildings up to 140′ clearspan with prefabricated wood trusses, 100′ is widest we have provided. Due to possible shipping and fabrication challenges, these spans are not available in all markets and further research would need to be done based upon your location and load conditions. A Hansen Pole Buildings’ Designer will be reaching out to you for further discussion.

DEAR POLE BARN GURU: Is a vapor barrier needed for metal roof if it is open, no walls? CRAIG.

DEAR CRAIG: While Building Codes do not require one – if it is absent you are likely to have periods (especially in Spring and Fall) where it will rain inside of your building. Most people erect new buildings with an idea of protecting contents from climactic conditions such as rain, so this result may be less than desirable.

I would recommend you order roof steel with a factory applied Integral Condensation Control (ICC). ICC is available with trade names such as Dripstop and Condenstop.

DEAR POLE BARN GURU: My wife and I may be obtaining property in western Oregon and have been kicking the idea around building such a structure. We really don’t know where to start and what this all entails. We really like the idea of having a simple open concept with a decent size shop attached so all our vehicles and RV can be stored inside. I was just really hoping to get a starting point and go from there. Thank you for your time! COLE in OREGON

DEAR COLE: Thank you for reaching out to us. Links in this article should assist you in getting off to a start in the right direction: https://www.hansenpolebuildings.com/2019/10/show-me-your-barndominium-plans-please/

This entry was posted in Roofing Materials, Pole Barn Planning, Trusses, Ventilation, Workshop Buildings, RV Storage, Pole Barn Questions, Building Styles and Designs and tagged roof only condensation, How To, vapor barrier, pole barn planning, building width, truss span on October 26, 2020 by admin.

Integral Condensation Control

With steel roofing for barndominiums, shouses and post frame (pole) buildings comes condensation.

When atmospheric conditions (in this case temperature and humidity) reach dew point, air’s vapor is able to condense to objects colder than surrounding air temperature. Once vapor condensing occurs, droplets are formed on cool surfaces. This is partly why warming a vehicle’s windshield with a defroster can prevent glass ‘fogging’.

When a building’s interior air meets these conditions, air vapor will condense to cool surfaces. Steel roofing cooled by exterior air temperature often provides this surface. Droplets formed will combine as they contact one another, continuing to do so until they are too large to be supported by surface tension. At this point, dripping will occur, essentially raining on your structure’s contents.

Commonly (when addressed at all during construction) solutions to this problem have often involved creating a thermal break. A thermal break reduces contact between a structure’s warm interior air and cooler metal roofing, thereby reducing or eliminating overall condensation. Installing a reflective radiant barrier, often termed Vapor Barrier, involves laying rolls of faced ‘bubble wrap’ across your building’s purlins prior to roof steel installation. Ideal weather conditions are required for this as even a slight wind can make this a challenging or altogether impossible task. This can cause jobsite delays and may bring progress to a halt while a structure remains unprotected to weather. Even when ideal weather conditions are present, installing a reflective radiant barrier can be a very dangerous task, requiring builders to expose themselves to awkward material handling on a building’s bare roof framing. These risks and delays often generate additional costs for both owners and builders, but have often been necessary with reflective radiant barrier being the only relatively affordable option to prevent interior dripping.

New materials and production methods offer a better solution. Utilizing polyester fabric’s absorption characteristics and their integral application during roll-forming, most better quality steel roofing roll formers offer a ready-to-install roofing panel with integral drip-protection. I.C.C. is a pre-applied solution reaching jobsites ready for immediate installation. Delays and increased jobsite workload caused by problems associated with radiant reflective barriers are eliminated by this product. Also, due to this solution’s simplicity, panels with I.C.C. install using the same methods, fasteners and time similar panel-only installations require. No changes to installation processes are necessary, with an exception of time and effort saved.

It works because this polyester membrane simply retains liquid until atmospheric conditions allow it to be re-evaporated. This is because polyester is hydrophilic, meaning water is attracted to it. It acts as a wick, harmlessly absorbing condensing vapor. Rather than preventing condensation, it provides an absorbent layer to detain condensing vapor until it can re-evaporate as temperatures increase and humidity decreases.

This entry was posted in Barndominium, Roofing Materials, Shouse, Pole Barn Planning, Steel Roofing & Siding and tagged shouse, hydrophilic, vapor barrier, condensation, barndominium, thermal break, I.C.C., reflective radiant barrier on September 3, 2020 by admin.

A Frustrated Shopper, Sealant Around Posts, and Vapor Barriers

Today’s Pole Barn Guru answers reader questions about a frustrating shopping experience, use of a sealant around embedded posts, and best method for a vapor barrier under concrete.

DEAR POLE BARN GURU: Hello my husband and I have been pre-approved to finance a pole barn and I am becoming very FRUSTRATED. We have called “Oscar ” multiple times with absolutely NO response and my concern is that it will be like this through the duration of the process, and should we go elsewhere? Or do I need to be reassigned to someone that will make us feel like a priority!!

Thank you for a speedy response. TIFFANI in TULSA

DEAR TIFFANI: Our apologies for your frustrations. Challenges do occur when people are building shopping, they have reached out to so many parties – causing names, businesses and conversations to become jumbled.

It turns out we happen to have no “Oscar” on our staff, nor do we show either you or your husband in our database. One of our Building Designers will be reaching out to you on our next business day to assist you with your building needs.

Let me assure you, every one of our clients is important and we pride ourselves in being responsive to you and your needs.

DEAR POLE BARN GURU: I am making a pole style garage. And I am wondering if I should be applying sealant around the cement that the Poles are embedded?

Help would be appreciated. EVERETT in DUCHESNE

DEAR EVERETT: There would be no reason to do so, provided you have used UC-4B rated pressure preservative treated timber columns. If they are treated to a lesser level of treating it is unlikely any amount of sealant will prevent their premature decay.

DEAR POLE BARN GURU: I have nearly completed my DIY Hansen Building and am preparing to pour the slab. Is there a way to search the blog posts for my questions? I am wondering if I should install a vapor barrier under the concrete or wait and seal it after? Is 1/2″ rebar recommended? Should I use an 18in grid or can I go on the cheap and get away with 2ft? Planning on a 5in slab. NICK in GLIDDEN

DEAR NICK: Good to hear from you, we are looking forward to seeing photos of your completed new building!

You should install a well-sealed vapor barrier under your slab, While Code requirement is 6mil, 15mil is far less likely to be damaged during a pour. Run vapor barrier up sides and onto top of 2×8 splash planks, overlap seams by at least six inches and tape them securely. Most often we see 1/2″ rebar on a 16″ grid.

This entry was posted in Ventilation, Concrete, Columns, Pole Barn Questions, Pole Barn Planning and tagged vapor barrier, post treatment, concrete vapor barrier, shopping experience, post frame shopping, sealant around post on July 27, 2020 by admin.

Attic Venting, Moisture Reduction, and a Vapor Barrier

This week the Pole Barn Guru answers reader questions about ventilation for an attic space, what type of insulation to use for the reduction or elimination of moisture, and to place a vapor barrier under the concrete slab.

DEAR POLE BARN GURU: I know you have answered a few questions regarding attic venting so I apologize if this is a repeat. I am looking at finishing the ceiling in my 24′ x 48′ pole barn with thin gage interior steel and blowing in insulation. I currently only have soffit on one gable end and I can see daylight coming in from under the trim on the other end. According to some other threads I have read, I need 3.84 sq. ft. of venting area. The gable end soffit is approximately 25 sq ft but I don’t know how much of that is free venting area. Do you count the whole 25 sq. ft? Also, any recommendations for what to do on the other end? Is the daylight that I can see coming in under the trim good enough? BRYCE in ZIMMERMAN

DEAR BRYCE: By Code you are unable to count any contribution from gable end soffits and areas between overhanging end purlins should be blocked solid to prevent airflow (and to properly create a load path to transfer shear forces from roof to ground). A construction flaw (such as daylight coming in under trim, probably should be fixed, rather than counted. By Code requirement is 3.84 square feet or 552.96 square inches of net free ventilating area located in upper 1/2 of your building’s attic space. My recommendation would be to install gable vents sufficient to provide airflow requirements.

DEAR POLE BARN GURU: What type of insulation do I need to keep out moisture in my residential building? JACLYN in WHITEHALL

DEAR JACLYN: Here is my ultimate guide to post frame building insulation https://www.hansenpolebuildings.com/2019/11/post-frame-building-insulation/

More important is removing sources of moisture https://www.hansenpolebuildings.com/2018/10/pole-barn-moisture-issues/

DEAR NICK: Good to hear from you, we are looking forward to seeing photos of your new building!

You should install a well-sealed vapor barrier under your slab while Code requirement is 6mil, however 15mil is far less likely to be damaged during a pour. Run vapor barrier up sides and onto top of 2×8 splash planks Overlap seams by at least 6″ and tape. Most often we see 1/2″ rebar on a 16″ grid.

This entry was posted in Pole Barn Questions, Building Overhangs, Ventilation, Concrete and tagged insulation, vapor barrier, gable vents, attic venting, concrete vapor barrier on July 6, 2020 by admin.

Should My Barndominium Have a Vapor Barrier?

Should My Barndominium Ceiling Have a Vapor Barrier?

With barndominiums, shouses (shop/house) and post frame homes becoming immensely popular, I have been learning more than I ever thought I wanted to learn about them. Rather than me just spewing on, today’s expert advice comes courtesy of building scientist Joe Lstiburek.

Plastic vapor barriers should only be installed in vented attics in climates with more than 8,000 heating degree days. You can forego the plastic and use a vapor retarder (kraft-faced insulation or latex ceiling paint) in all other climates except hot-humid or hot-dry climates. In hot-humid climates, attics should not be vented and vapor retarders should not be installed on the interior of assemblies.

In hot-dry climates a vapor retarder should also not be installed, but attics can be vented. All attics — vented or unvented — should have an air barrier (a properly detailed airtight drywall ceiling, for example) regardless of climate.

Omitting a ceiling vapor barrier by arguing that “you have to let the moisture escape” or “because the house has to breathe out the top” is actually correct, in a way. It’s also incorrect, in a way. Now, I’m a real fan (ha, ha) of controlled mechanical ventilation to limit interior moisture levels in cold and mixed climates, as well as to limit other interior contaminants in all climates. In other words, all houses require controlled mechanical ventilation in order to “breathe.” It is also my view that this necessary air change should not happen because of a leaky attic ceiling, attic vents, or even leaky walls. Hence the requirement for an air barrier and controlled mechanical ventilation in all houses regardless of climate.

Having said that, I do not have a problem with relieving some of the moisture load in the house via diffusion. This can be achieved through a roof assembly designed to handle it, such as a vented attic in a moderately cold or mixed climate. It’s important to understand that this is a climate-specific recommendation. In a well insulated attic in a very cold climate (more than 8,000 heating degree days), there is not enough heat loss into an attic from the house to allow for much moisture removal through ventilation. That’s because attic ventilation requires heat loss to remove moisture from attics. Cold air can’t hold much moisture. So ventilating a heavily insulated attic with outside air when it is really cold does not remove moisture. We do not want any moisture to get into an attic in a severely cold climate for this reason. As you move south into regions where it is not so miserably cold, this changes: Hence, the recommendation for a vapor barrier in a severely cold climate but only a vapor retarder in most other locations.

There’s one other important qualification: Vapor moves in two ways, by diffusion through materials, and by air leakage through gaps and holes in building assemblies. Between the two, air leakage moves far more moisture than vapor diffusion. A vapor barrier in an attic assembly in a severely cold climate with the absence of an air barrier will likely be ineffective. On the other hand, an air barrier (a properly detailed air-tight drywall ceiling, for example) in the absence of a vapor barrier can be effective, since it stops the flow of vapor-laden air. You can’t just install plastic in a ceiling and assume it is also an air barrier. For plastic to be an air barrier, it needs to be continuous, meaning all joints and penetrations must be taped or caulked.

Mike the Pole Barn Guru; Good stuff to remember. Thanks Joe!

This entry was posted in Pole Barn Homes, Pole Barn Heating, Post Frame Home, Barndominium, Shouse, Insulation, Pole Barn Design, Ventilation and tagged attic ventilation, Air barrier, air leakage, insulation, attic moisture, vapor barrier, controlled mechanical ventilation on March 17, 2020 by admin.

Condensation Above Metal Building Roof Insulation

Only those few long time readers or those who had time on their hands and have read every blog I ever wrote will recall this story about my adventures with metal building roof insulation: https://www.hansenpolebuildings.com/2011/11/metal-building-insulation-in-pole-buildings-part-i/.

Reader JOSH in CORVALLIS is having issues with how metal building insulation is (or in his case is not) performing in his post frame hangar. He writes:

“I am a first time builder and finished a 40×50 Hangar by myself a few years ago. It all came out perfectly with one exception. Every year when the temperatures change rapidly and the moisture is high I get condensation that fills up the roof insulation along the intersection of the roof and the top girt.

I used fiberglass backed with vinyl laid under the metal roofing. When I installed it I rolled it out from one side of the building up over the peak and down to the other side in a continuous piece. Each piece then was overlapped to the next one, folded over and stapled down to the purlin. I feel that was done well. Where the insulation meets the top girt (purlin) I finished it off there by folding it over on itself and stapled it to the top of the top girt (purlin) so the metal roofing was laid on top of it and screwed down to that top girt (purlin) only touching the vinyl backing.

At the peak of the roof I have a gap of a few inches between the sheet metal from one side to the other, with the ridge cap covering that gap. I used a duckbill plier tool to bend up the sheet metal along the top edge before installing the ridge cap to help keep out a driving rain but let air flow through.

The roofing tips I had received from other DIY builders influenced the way I did things and I now question if those things are causing this condensation issue I have. The 3 main things are how I tacked the insulation to the top girt (purlin) by folding it over onto itself. The droop of the insulation between each purlin (about 2 inches droop), now I think that maybe should be taut against the metal. And the bending of the metal sheet up under the ridgecap as I see they sell matching foam insulation strips for this area which would obviously block airflow as well as water. So my question is what did I do wrong here and what can I do to correct it?”

Mike the Pole Barn Guru writes:
I lived for a decade roughly 40 miles northeast of you in South Salem so am vaguely familiar with your weather – two seasons, warm rain and cold rain. Now seriously, it was not so bad, until I moved back to Eastern Washington’s high desert and had to have webbing removal surgery from between my fingers.

I have given your scenario some serious thought since you wrote with your challenge.

My general method of problem solving begins with what is causing this situation, beginning with possible sources.

Usually I would point my finger at roof leaks, however you have narrowed this down to only when humidity is high. Most often increased humidity inside of buildings is due to no vapor barrier beneath a slab-on-grade. If this is your particular circumstance, I would recommend applying a sealant to your concrete floor.

Normally when water is collecting just uphill of an eave strut (aka eave purlin or girt) it is due to a raw insulation edge on top of the eave strut. You have eliminated this, however humidity laden air can still enter your system here unless you place inside closures between your fold over and roof steel (my guess is this is your source) https://www.hansenpolebuildings.com/2015/12/the-lowly-inside-closure/

Using Metal Building Insulation as a Condensation Control usually fails due to seams being poorly sealed. A 100% tight seal is essential for adequate performance. Here is how they should be done:

You have no airflow at your ridge, due to having run insulation continuous from eave-to-eave. I would cut away insulation between your ridge purlins and install vented closure strips under your ridge cap. This will give a point for warm moist air to exhaust from inside your building and prevent any blown rain from entering.

I hope this helps….please let me know how it all works once you apply the remedy.

This entry was posted in Ventilation, Concrete, Insulation, Pole Barn Questions, Roofing Materials, Pole Building How To Guides, Pole Barn Planning and tagged inside closures, eave strut, top girt, top purlin, vapor barrier, condensation, metal building insulation on March 3, 2020 by admin.

Post Frame Condensation and Insulation Challenge

Solving Yet Another Post Frame Condensation and Insulation Challenge

Long time loyal readers will sigh as yet another post frame building has been erected without thoughts to how to properly insulate and control condensation. Had our new friend invested in a Hansen Pole Building, chances are good we would not be having this question and I would have had to write about something else today! Our Building Designers follow with these recommendations: https://www.hansenpolebuildings.com/2019/11/post-frame-building-insulation/.

Our new friend COREY in POST FALLS writes:

“I have a 36×48 pole building with trusses on 12’ with BCDL 5psf, the roof is plywood sheeted with composition roofing with ridge vent and gable vents. The wall Purlins are on the exterior of the poles and there is no vapor barrier. I would like to install a ceiling with insulation and insulate the walls. I am looking for vapor barrier and insulation recommendations. Was thinking of installing 2×4 on 24 centers to bottom of trusses and installing OSB and blown in insulation, and then framing in between poles adding batt insulation and sheeting with OSB, but am unsure of controlling vapor. Thank you.”

Mike the Pole Barn Guru responds:

Small world, many years ago I graduated from Post Falls High School!

A vented ridge relying upon gable vents as an air intake is usually very inefficient. You should make sure your vents in each end are located in the top half of your attic and have at least 415 square inches of net free ventilating area on each end. This means you are probably going to have to add more vents. Effective ventilation of this area is essential to preventing mold and mildew in your attic.

Wall girts flat on column exteriors are inadequate to carry imposed loads and will not meet deflection limitations. I would suggest you reinforce each of them to create either an “L” or a “T”. Assuming you have 6×6 wall columns, you could place a 2×8 bookshelf style girt on top or bottom of each girt, nailing through 2×8 into existing girts with a 10d common nail at say 12 inches on center. This will create an insulation cavity and allow for easy interior finish.

For ceiling joists between your trusses, 2×4 will not be adequate you should use 2×6 #2 with joist hangers on each end.

Unless you have a Weather Resistant Barrier (https://www.hansenpolebuildings.com/2016/01/determining-the-most-effective-building-weather-resistant-barrier-part-1/) between framing and wall steel, my recommendation would be to have two inches of closed cell insulation spray foam to the inside of wall steel. Then fill balance of wall cavity with BIBs insulation: https://www.hansenpolebuildings.com/2011/11/bibs/ with a well sealed vapor barrier towards the inside space.

This entry was posted in Barndominium, Insulation, Ventilation, Pole Barn Questions, Building Interior, Pole Barn Design, Pole Building How To Guides, Pole Barn Homes, Pole Barn Planning, Pole Barn Structure and tagged vented ridge, insulation, vapor barrier, barndominium condensation, condensation, BIBS insulation, batt insulation, gable vents, bookshelf wall girts on December 4, 2019 by admin.

Post Frame Indoor Swimming Pool Considerations

In my past life I lived with my family in Oregon’s Willamette Valley. Hot summer days filled with sunshine were about as rare as access to nearby lakes – close to zero. Having grown up spending summers at my maternal grandparents’ lake cabin, swimming has always been part of my life. A frequently told fable was my younger brother and I could swim before we could walk!

Given relatively mild winter weather, I opted to have an in-ground outdoor swimming pool added to our backyard. Many an hour was spent in this pool, prior to selling and moving back to my native Spokane area.

Reader CLINT in COLUMBUS writes:
“Saw a post about pole barn over an in ground pool.
Curious about moisture management? My pool builder says a lot of cost but won’t expand on it.”

Mike the Pole Barn Guru responds:
Indoor pools demand special monitoring for constant challenge of humidity control. Service pros shouldn’t be expected to maintain dehumidifiers, which are HVAC/R machines requiring EPA-certified technicians. Indoor pools can malfunction quickly, so a typical six-month or annual dehumidifier check-up by an HVAC/R service contractor isn’t enough to detect potentially damaging problems before they blossom.

An indoor pool is a unique synergy of four factors, degradation of any could result in building deterioration, air quality health problems and uncomfortable environmental conditions for users.

1. Building envelope: Indoor pools can experience issues related to construction techniques or building materials. For example, missing or breached vapor barriers can allow damaging condensation to accumulate inside walls. For post frame pool covers, I would recommend use of all pressure preservative treated lumber. Walls must have a totally sealed interior vapor barrier. Depending upon climate, adding a layer of two inch closed cell rigid insulation board to inside of framing reduces thermal transmission between interior and exterior and can be air sealed.

2. Ventilation: Supply air ducts and vents must fully cover exterior windows with conditioned air to avoid condensation. System must move air down to breathing zone for good air quality.

3. Dehumidification: Most indoor pool spaces have a dehumidifier to maintain 50- to 60 percent relative humidity and cool or heat air to a set point temperature. Without it, the space probably depends on outdoor air and exhaust.

4. Water chemistry: Imbalanced chemistry results in buildup of respiratory-affecting chloramines and potentially causing surfaces to corrode.

Most modern dehumidifiers are complete HVAC machines heating or cooling space and use compressor heat recovery to heat pool water.

So space and water temperatures, and relative humidity are key checkpoints. These parameters are displayed on a microprocessor’s LED keypad readout and in many cases can be accessed remotely. A good rule of thumb is to keep a two-degree difference between space (higher) and water (lower) temperatures. A common indoor pool set point is 84°F space, 82°F water temperature and a 60 percent relative humidity. Lowering space temperature by even two degrees increases humidity load by 35 percent, which could surpass a dehumidifier’s capacity.

Many dehumidifier LED keypads have red warning lights to indicate an operation stoppage or problems, which only an HVAC/R technician can repair. This readout menu can be scrolled to find a cause.

No water should leak from inlets or outlets of dehumidifiers with a pool water heating feature. On the other hand, hundreds of pool water heating models have been errantly left unconnected to the pool’s circulation systems. Owners should know water heating connection to a dehumidifier could save hundreds of dollars on utility bills annually.

An overflowing condensate drain pan (or watermark evidence) could point to a potentially damaging drain line blockage.

Condensation on exterior walls and ceilings should not occur. Window and skylight condensation indicates the glass is not covered with warm dehumidified supply air and its temperature has dropped below the dew point.

Premature corrosion on door hardware or room surfaces could indicate a problem.
Indoor pools must operate with a negative building pressure: Approximately 10 percent more air volume should be exhausted than introduced. A malfunctioning exhaust fan or ventilation design can result in positive pressure and push pool air and odors into connected living quarters. Positive pressurization also can push moisture into poorly sealed voids inside walls and above ceilings where it can produce mold and deteriorate the building. Indoor pool building pressure can be easily checked by slightly opening a door and seeing if air is being pulled in (negative) or pushed out (positive).

Dehumidifier supply air blowers generally run 24/7 to offset pool evaporation, so monthly or bi-monthly air-filter replacements may be needed. If the blower isn’t running, there’s something amiss.

Dehumidifier compressors run at least 10 minutes at a time. Hearing compressor short-cycle off and on several times within a minute or two warrants an HVAC/R service contractor’s attention. Very noisy ductwork, such as drum head effects and extreme vibrations, could point to a poor ventilation design. Unusual sounds, such as fan belts squealing or worn out motor or blower bearings, also require an HVAC/R contractor.

A final note: Suggesting owners call their dehumidifier maker rather than an HVAC/R contractor usually won’t help because they rarely perform repairs. However, a factory tech’s review of data can help HVAC/R service pros troubleshoot issues.

This entry was posted in Post Frame Home, Pole Barn Questions, Barndominium, About The Pole Barn Guru, Pole Building How To Guides, Pole Barn Planning, Ventilation, Building Interior and tagged swimming pool ventilation, dehumidification, swimming pool water chemistry, vapor barrier, Ventilation, Post Frame Buildings HVAC, closed cell rigid insulation on August 27, 2019 by admin.

Vapor Barrier, Replacement Skylights, and Frost Heave

This week the Pole Barn Guru answers questions about vapor barrier, a solution for skylights, and how to reduce frost heave.

DEAR POLE BARN GURU: Vapor barrier under roof metal or under trusses with insulation on top?
I find never-ending opinions about where to place vapor barrier in a post frame building.
If the space is to be insulated would it not be better to put nothing directly under the roof metal and put a vapor barrier on the ceiling with insulation above that?
Everyone says to put on single or double bubble before putting down roof metal but if I do that how do I insulate the ceiling because then I will have a vapor barrier above the insulation. DAVID in KIRKWOOD

DEAR DAVID: Vapor barrier under roof steel if you are creating a dead attic space. It is essential to prevent warm moist air from within your attic from reaching underside of roof steel. My preference would be to use roof steel with Dripstop (https://www.hansenpolebuildings.com/2017/03/integral-condensation-control/) or Condenstop (https://www.hansenpolebuildings.com/2014/07/condenstop/) applied.

Do not place a vapor barrier between ceiling sheetrock and attic insulation. Do properly ventilate your dead attic space as Code requires (https://www.hansenpolebuildings.com/2018/03/adequate-eave-ridge-ventilation/).

DEAR POLE BARN GURU: I have a pole shed 1972? with skylights that need replacing where do I find . DAVE in COLFAX

DEAR DAVE: One of my previous questioners had a similar issue, you might want to read here: https://www.hansenpolebuildings.com/2018/08/sky-lights-leaking/.

DEAR POLE BARN GURU: What do you recommend for creating a frost wall around a post frame (posts in the ground) structure. The posts are dug down below frost level, so the footings are protected. But if the interior floor is a slab poured on grade, what is the best way to protect this slab from frost heave?
Thank you, CHRIS in NEW HOLLAND

DEAR CHRIS: Good to hear from you! (side note – Chris is a personal friend of mine) There is a relatively simple solution for this – do the post frame version of a shallow frost protected foundation: https://www.hansenpolebuildings.com/2017/09/post-frame-frost-walls/.

This entry was posted in Pole Barn Questions, Roofing Materials, Steel Roofing & Siding, Ventilation, Concrete, Footings, Insulation and tagged vapor barrier, skylights, frost heave on August 5, 2019 by admin.

Will I Have Moisture Issues?

Condensation and moisture issues in any building can be problematic. No one purposely designs a building with an idea to have dripping from under roof condensation, or mold and mildew from trapped moisture.

Hansen Pole Buildings’ client and loyal reader KURT in SAINT HELENS writes:

“Hello,
Question about roof insulation. Plan on insulating 2″ double-laminated with WMP-VR on one side and FSK-HD Foil facing on the other. Layers for the roof will consist of metal roofing, 30# roofing felt, 1/2 plywood and the insulation. Will I have moisture issues with this configuration?
Thanks for your input.”

Mike the Pole Barn Guru responds:

Thank you for your question Kurt, obviously you have given a great deal of thought to condensation and moisture issues in your new post frame building.

Your layer of plywood and felt will provide a thermal break preventing any warm moist air inside of your building from contacting with a cooler steel roof.

For those interested, here is some light reading about WMP-VR https://www.hansenpolebuildings.com/2014/10/metal-building-insulation-2/, a faced metal building “insulation”.

FSK facing, or foil-scrim-kraft is a flame retardant vapor-barrier. It is one of the most commonly used facings in today’s insulation industry. During manufacturing processes of an FSK facing, a layer of lightweight aluminum foil is layered against a tri-directional, reinforcing fiberglass scrim (yarn) and then paired with a final layer of natural brown kraft paper. This is all laminated together using a flame-retardant adhesive.

Once this process is complete, facing is rolled into a giant master roll and delivered to a fiberglass manufacturing facility. This is where manufactured fiberglass insulation is adhered to facing’s kraft paper side.

FSK facing is most commonly utilized with duct wrap, duct board, and mechanical spin-glas boards on outward-facing, exposed surfaces of HVAC ductwork. This FSK facing not only serves as a vapor-barrier to facilitate condensation control, but it is also a protective barrier for fiberglass insulation itself. Aluminum foil gives FSK its distinctive silver color and can typically be easily recognized on any HVAC system.

This two inch thick metal building “insulation” is going to be an unnecessary expense and will provide little or no actual insulating value. As long as you have adequate ventilation (both intake and exhaust) and your concrete floor has a well- sealed high quality vapor barrier below it, you should not experience moisture issues. Keep in mind – in the months immediately following pouring your concrete slab, expect to have excess moisture within your building. Once your concrete floor has cured, these issues should go away.

This entry was posted in Pole Barn Questions, Pole Barn Design, Pole Building How To Guides, Pole Barn Planning, Ventilation, Building Interior, Uncategorized, Insulation and tagged WMP-VR, vapor barrier, fiberglass insulation, FSK Facing, kraft paper on July 23, 2019 by admin.

Pole Barn Guru Blog Review

This is the third year the Pole Barn Guru blog has been in competition for the Best Construction Blog. Last year this blog was second in the world, tying for first in quality, however losing the popular vote. Part of this process is a review of each blog by Mark Buckshon of Construction Marketing Ideas (www.ConstructionMarketingIdeas.com).

Below is Mr. Buckshon’s review:

Hansen Buildings’ Pole Barn Guru: Practical information about post frame (pole barn) structures

By Mark Buckshon

–March 23, 2019

The Pole Barn Guru is currently leading in the 2018 Best Construction Blog’s popular vote and unless there is a surprising surge from supporters of another blog by the popular vote’s conclusion on March 31, this blog will probably earn the popular vote win status.

There are reasons for this support — the blog combines depth and focus as a “go to” resource for post frame (pole barn) buildings; and it doesn’t avoid the challenges with these low-cost structures, often used for outdoor storage and as rural outbuildings.

I’ve been reading some posts, for example, dealing with issues relating to condensation and insulation, some initiated by questions from outsiders — that is folks who have a pole barn structure not provided by Hansen.

Rather than brushing off these external inquiries with a: “Hey, that’s not my problem” attitude, this blog provides some practical answers, even as it indicates the issues probably wouldn’t have been problems if they had been considered in the initial design and purchase.

That educational aspect makes this blog truly worthy.

Consider, for example, this question in a recent blog post:

Hello!

I have a pre-existing pole building that I am having a ton of trouble with. It is partitioned into two rooms, the back room is heated to around 50F. The attic space/loft space has a lot of condensation and I cannot seem to get this fixed. I have tried a lot of solutions, none of which have worked. I know that you build these types of buildings so I am hoping that you can recommend someone who might be able to come in and look at this issue and help me with a solution that works. I have no idea what to do next and I am a local business owner – my business is at a standstill right now until I can get this issue fixed. If you can recommend any general contractor, or anyone who might have expertise in pole buildings who I can contact I would greatly appreciate it.

Thank you so much!”

The question is posed after a brief introduction:

Long time readers should be thoroughly drenched with solutions to condensation issues by now. As post frame construction has moved off farms and into suburbia, climate control has brought with it a plethora of condensation challenges.

So, what are the answers?

To control your condensation challenge you need to either remove warm moist air from inside your building, prevent this air from becoming in contact with surfaces at or below dew point, heat and/or ventilate. Here’s a brief summary, followed by solutions specific to your case: https://www.hansenpolebuildings.com/2019/02/how-to-reduce-condensation-in-post-frame-buildings/.

If you do not have some sort of thermal break below your pole building’s roof steel – two inches of closed cell spray foam should be applied. This process will be best done by a professional installer. Make certain to not block ventilation intake and exhaust points.

Unless you know for certain a vapor barrier was placed under your building’s concrete slab, seal the floor. https://www.hansenpolebuildings.com/2019/02/how-to-properly-apply-post-frame-concrete-sealant/

and https://www.hansenpolebuildings.com/2018/11/siloxa-tek-8505-concrete-sealant/.

Vent any dead attic spaces. https://www.hansenpolebuildings.com/2018/03/adequate-eave-ridge-ventilation/.

Heating your building to a temperature above dew point will also solve this issue. Avoid heating with propane, as it adds moisture to the air.

Now in my opinion, that sort of detailed, practical advice shows how an effective, consistent and useful blog can provide real value to clients and potential customers alike (and serve a general community purpose, even for people who will never purchase a thing from Hansen.)

This value translates to search engine effectiveness and of course a reputation for knowledge and service. If you are thinking about purchasing a post frame structure, for example, I’m confident after reading through the relevant blog postings you’ll have the confidence to ask the right questions and share the site/usage observations to ensure that the structure serves its purpose and problems such as condensation or poor insulation don’t occur in the first place.

This entry was posted in Pole Barn Structure, Ventilation, Uncategorized, Insulation, Pole Barn Questions, Pole Barn Design, About The Pole Barn Guru, Pole Barn Planning and tagged vapor barrier, condensation, Ventilation, pole barn condensation, Construction Marketing Ideas, dead attic space, closed cell foam insulation, closed cell spray foam on April 10, 2019 by admin.

How to Wire a Winch, Floor Vapor Barrier, and Floor Sealant

Today the Pole Barn Guru assists reader with wiring a winch, vapor barriers for a floor, and floor sealant.

DEAR POLE BARN GURU: Do you know how to wire ATV warn winch to make electric winch boxes? MAX in SPOKANE

DEAR MAX: Thanks to magical miracles of internet and Google here is where you can locate appropriate wiring diagrams: https://images.search.yahoo.com/search/images?p=wiring+a+warn+winch+to+110+volts+diagram&fr=crmas&imgurl=https%3A%2F%2Ftops-stars.com%2Fwp-content%2Fuploads%2F2017%2F09%2Fwarn-winch-wiring-diagram-solenoid-how-to-wire-up-a-warn-m8000-regarding-warn-winch-controller-wiring-diagram.jpg#id=1&iurl=http%3A%2F%2Fcssmith.co%2Fwp-content%2Fuploads%2F2017%2F11%2Fwarn-winch-solenoid-diagram-starter-wiring-for-illustration-enjoyable.jpg&action=click

DEAR POLE BARN GURU: Should I put plastic down under the stone floor in a steel building? BOB in WYALUSING

DEAR BOB: It certainly could not hurt and might help to lower humidity within your building, as well as minimize or eliminate condensation challenges. Look for a 15 mil poly. Here is some more information on vapor barriers: https://www.hansenpolebuildings.com/2017/11/vapor-barriers-slabs-grades/

DEAR POLE BARN GURU: I have a garage without moisture barrier beneath. Is it possible to seal this? Thanks for any info you might have. SAM in EUFAULA

DEAR SAM: Chances are good you can use a sealant upon your concrete floor to keep some or all ground moisture from migrating through.

Here is how to properly apply a sealant: https://www.hansenpolebuildings.com/2019/02/how-to-properly-apply-post-frame-concrete-sealant/.

And information about one sealant in particular: https://www.hansenpolebuildings.com/2018/11/siloxa-tek-8505-concrete-sealant/.

This entry was posted in Pole Building How To Guides, Ventilation, Concrete, Building Interior and tagged vapor barrier, wiring, floor sealant, winch on April 1, 2019 by admin.

Participating in Rick’s Post Frame Cabin Planning

Happy readers have been following Hansen Pole Buildings’ Designer Rick’s journey towards constructing a new cabin. Rick has graciously asked me to jump in with sage advice (yep, Rick and I are both old guys), as well as answering some questions he has posed.

Rick mentions using a vapor barrier under his thin concrete slab. This should be a minimum 10 mil with 15 mil being even better in resistance to possible tears prior to floor being poured. (https://www.hansenpolebuildings.com/2017/11/vapor-barriers-slabs-grades/)

I’d believe Rick’s cabin floor could be insulated with closed cell spray foam two inches thick, providing approximately R-14. Any wiring or plumbing extending through sub-flooring could be routed directly vertical through foam and this should not pose a challenge of access for any future system modifications.

As only incidental heat will be provided into crawl space areas, using rigid foam insulation boards beneath a thin concrete slab might very well prove to be an undue expense.

Rick’s sub-slab insulation boards (if used) and approximately two inches of concrete will not pose any design issues when used with a 2×8 pressure preservative treated splash plank. With top of floor OSB three feet above grade, a clear height in crawl space of two feet will exist under the floor joists. A row of stub columns at building center will carry beams designed to support joists. Given relatively small floor joist and beam spans, there would be 20 inches or more between concrete and the bottom of beams.

A consideration for wall insulation might be to use a flash coating of two inches of closed cell foam against siding, then fill remainder of wall cavity with BIBs. This would eliminate a need for a Weather Resistant Barrier beneath siding and would provide as much as R-35 insulating value. If looking to super insulate and eliminate any thermal bridging, two inches of insulation board could be glued to inside of framing, further increasing R value.

So far, I am liking Rick’s plan of attack and look forward to reading more along his path to his best possible design solution.

This entry was posted in Footings, Insulation, Pole Barn Questions, Pole Barn Planning, Pole Barn Structure, Concrete and tagged closed cell foam, crawl space insulation, cabin planning, insulation, vapor barrier, BIBS insulation on March 26, 2019 by admin.

More Condensation Fun

Reader KRYSTA in SPOKANE writes:

“Hello!

Thank you so much!”

Mike the Pole Barn Guru writes:

Vent any dead attic spaces. https://www.hansenpolebuildings.com/2018/03/adequate-eave-ridge-ventilation/.

Heating your building to a temperature above dew point will also solve this issue. Avoid heating with propane, as it adds moisture to the air.

This entry was posted in Insulation, Pole Barn Questions, Pole Building How To Guides, Ventilation, Concrete, Building Interior, Pole Barn Heating and tagged dead attic spaces, dew point, propane heat, vapor barrier, thermal break, closed cell spray foam, concrete sealer on March 13, 2019 by admin.

Insulation, Insulation, Insulation

The Pole Barn Guru discusses the always popular ceiling insulation, vapor barriers with insulation, and closed cell spray foam insulation.

DEAR POLE BARN GURU: I read your article on unvented roofs. My building has a vapor barrier installed. I am at the point of insulation and plan on doing closed cell spray foam. What would be better spraying the roof deck or the attic floor/ top side of the ceiling. I was thinking spraying the roof deck and then doing blown in insulation above the ceiling to get my r value. I thought having the entire building done in closed cell would make for the tightest building. BRAD in FLANAGAN

DEAR BRAD: If you have a condensation control barrier (having a thermal break, not just a vapor barrier) of some kind between roof steel and framing, then there would be no need to closed cell spray foam underside of roof deck, unless you are going to use this as your only insulation. Insulating ceiling line creates a dead attic space above, so it will need to be ventilated (either eave and ridge or gable vents). Closed cell spray foam will give you a very air tight building, applied properly.

DEAR POLE BARN GURU: Built pole barn installed 1-2 inch thermal sheathing in outside installed 8 inch batt would you install vapor barrier on inside been told I have two vapor barriers answers. JIM in HARTFORD

DEAR JIM: You are going to have insulation sandwiched between two vapor barriers, however air leakage into the cavity is a greater issue than through a vapor barrier. Goal is to keep insulation and wall framing dry. As long as you adequately seal all of the air leakage pathways you would not need an interior vapor barrier. In other words – if you install an electrical outlet or switch box, seal it, seal around any door or window openings.

DEAR POLE BARN GURU: What do you feel is best insulation system for pole buildings building we got is 162 x 72 wood structure built on foundation wall columns on 6 ft on center girts nailed to outside of columns and also inside corrugated metal we installed 1/2 poly iso insulation and 8 inch batts in wall spray foamed base to seal air leaks and plugged holes on top with 3 inch iso between columns and foamed around window frames poly iso has foil face and we taped seams wanted to install poly vapor barrier on inside but was told that I would have two vapor barriers which is bad what do you recommend? JIM in HARTFORD

DEAR JIM: My recommendation would be two inches of closed cell spray foam on inside of steel siding. Install another set of girts on inside of columns to support interior wall finish material. Fill wall cavity with BIBs (https://www.hansenpolebuildings.com/2011/11/bibs/). Glue two inches of closed cell foam insulation board on inside of girts, sealing around any penetrations. Glue interior finish material to inside of insulation board.

This entry was posted in Insulation, Ventilation and tagged ceiling insulation, close cell spray foam, insulation, vapor barrier on March 11, 2019 by admin.

Minimizing Excavation in Post Frame Buildings Part II

Minimizing Excavation In Combination With Post-Frame Frost Protected Shallow Foundations Part II

In our last thrilling episode Snidely Whiplash had tied our fair damsel in distress, Nell Fenwick, to railroad tracks.

Oops – railroad engineers are not what most of you were expecting!

Continuing with a simplified solution response to reader DAVID’s ideas regarding site preparation and Shallow Frost Protected Foundations (SFPF) for post frame buildings.

Dear David ~

Thank you for your patience. As you may know from reading this column, I tend to research everything to best of my abilities prior to writing an article or responding to questions. Areas of site preparation and concrete flatwork are ones where I have a more limited amount of personal experience, so I have been doing a plethora of reading and contacting (and discussing) with concrete experts. I also am not married to a position, as better information becomes available, I take advantage of it.

Article you reference in (1) has been updated since you last perused it. Even though many RDP (Registered Design Professionals – architects and engineers) specify sand over under slab vapor barriers, I have now become a “no sand above vapor barrier” school convert.

To follow, a summation of my thoughts in regards to this subject, with top of slab being fixed 3-1/2” above grade.

(a) Excavate entire site to remove organic materials. Area to be excavated should be a minimum of three feet outside of actual building foot print. Depth of excavation below zero point (grade) should allow for any concrete thickness greater than a nominal four inches (3-1/2″ actual), two inches of insulation board (if desired), two to six inches of sand or sandy gravel and six to 12 inches of sub base. Assuming a nominal four inch slab, total depth of excavation should be 16 inches if doing a FPSF.

(b) Auger holes for columns, stand columns in augered holes and backfill with concrete per engineered plans.

(c) Install splash plank/skirt board, with board bottom even with grade (zero). There would be no reason to increase dimension to greater than 2×8, as vertical insulation boards prevent any concrete in a slab thickness greater than a nominal four inches to “leak” to outside world.

Side bar – 2×10 or 2×12 pressure preservative treated material will be available, however many times only via special order. If any portion were to be entirely embedded below grade, then appropriate treatment level would more probably be UC-4B – as UC-4A treatment levels are strictly for ground contact.

(d) Place vertical and horizontal insulation boards for FPSF – backfilling with sand or sandy gravel sufficiently to hold vertical insulation boards in place.

(e) Place sub-base, then base material, compacting in lifts.

(f) Place 15mil vapor barrier (make sure to run it up insides of splash planks); Under slab insulation (as desired); pex (https://www.hansenpolebuildings.com/2016/08/pex-tubing/), rebar and/or mesh, and then pour the slab.

This minimizes excavation by eliminating need for a trench.

This entry was posted in Concrete, Footings, Insulation, Pole Barn Questions, Pole Barn Design, Pole Building How To Guides and tagged insulation board, skirt board, UC-4B, Frost Protected Shallow Foundation, sub base, vapor barrier on February 14, 2019 by admin.

Minimizing Excavation in Post Frame Buildings

Minimizing Excavation In Combination With Post-Frame Frost Protected Shallow Foundations

Regular readers of this column recognize a groundswell movement towards energy efficient post frame building design.

Reader (and Mechanical Engineer) DAVID in CONNECTICUT had some thoughts (after reading a volume of my article pages) in regards to FPSF (Frost Protected Shallow Foundations) and radiant in floor heat.

He writes:

Good Morning, Mike!

In regards to this post, I’m having a lot of trouble understanding just how this all fits together…

https://www.hansenpolebuildings.com/2012/09/concrete-slab-3/

Firstly, I have read thru many (if not all) of your blog posts about foundations/slabs, browsed more than 40 pages of 80 blog list pages, as well as plenty of external references. Thanks for all the info you’ve put up! So trust me I’m not just trolling and looking for inconsistencies, just trying to get the best understanding possible before building and hoping to condense some of the knowledge that is spread through your blogs. I‘m a mechanical engineer by trade but my thoughts stray into many other areas! Because of your focus on engineering, Hansen is a front runner for getting my money. Also, I thought maybe I could contribute to the evolution of your build process to make things easier for the insulated slab folks here in frost country! I am in CT, frost and cold are an issue for heating my near-future garage. I’d like to run PEX in slab, and r10 foam under slab was recommended for max efficiency. How to install PEX Tubing in a concrete slab I’ll also likely be doing at least a partial FPSF at the edges.

In your blogs there seems to be a little bit of conflict on what you recommend for site prep.

Here, in the “thoughts” section at the bottom, https://www.hansenpolebuildings.com/2011/11/soil-compaction-how-to/ you recommend the gravel go in after the posts, but that seems to require plenty of back excavation to get the recommended gravel depth. How is the builder supposed to remove 6+ inches of ground from underneath and not disturb the soil under the skirt board? Plus, in the case of the people to do have gravel put in, you just spent all that effort putting it in and compacting it now you have to dig it out?
What I read at the “concrete slab -3” link above seems to indicate that I do organic removal, use at least 6”of properly compacted crushed processed stone to bring it back to (or just above) the previous grade, build the structure with skirt/splash board on that grade. Then for a 4” slab, re-excavate down 2 more inches for the insulation/ vapor barrier. That might be fine, but you also mention “prior to pouring (concrete),” use 2-6 inches of sand/ sandy gravel below the vapor barrier and 3-4 inches of sand above it. That would be a minimum of 5 additional inches (+2 for foam= 7”) of internal excavation after building! Or did you mean the first layer of sandy gravel would go on-grade and be built on? That’s still 5 total inches of post-build excavation (3 more of sand + 2″ of insulation board). Something still doesn’t quite add up. Not to mention the effort/ difficulty of re-leveling and re-tamping the internal excavated surface again!
You specifically mention in several places never to exceed 3.5” up the 2×8 skirt board, which is also fine, but what if we look into deeper slabs and less work to excavate? What if we did all the gravel/sand down 2” from FINAL grade, and used a 2×10 ground contact skirt board? Then there would be no interior excavating. I designate “final” grade because the area would be leveled, then building built and 2” backfilled against the skirt. OR in the case of a FPSF, the vertical insulation would be there anyhow. If there must be 2” of sandy mix above and below the vapor barrier you could use a 2 x12 skirt, right?

4. Also this article recommends against sand pre-pour. https://www.concreteconstruction.net/how-to/site-prep/subgrades-and-subbases-for-slabs_o Thoughts on that?

5. Lastly, I had an idea to more easily prep the area for both insulated slabs and FPSF. This also prevents disturbance of the sub-grade area during the install of the FPSF external insulation. Please see the illustration below.

6. Prep the area with appropriate sub-base compacted gravel but at a lower than “finished grade” level. This would be an area consisting of the building size plus 3 to 5 feet in each direction.

7. Install the poles and footers.

8. Install the 2 x12 skirt board on surface of the lower than final grade area.

9. Trench the outside for the vertical and horizontal FPSF insulation,

Backfill in lifts, compact, and re-grade the area outside the skirt board insulation. This supports the subgrade area UNDER the skirt board and behind the insulation so you don’t accidentally leave voids behind it.

THEN you add and compact the material inside the skirt board like sand/ stone-dust, vapor barrier, insulation foam, rebar and PEX tubing. This prevents weakening of the material under the skirtboard as well, because it’s never disturbed!

Last you pour 4” of concrete leaving a 3.5” reveal and you have the same post length, siding material and eave height/ clear height as before.

Can you even get 2 x 12s treated that might work in this application? Is UC-4B needed as it’s not exactly structural, right? Plus it’s surrounded by foam and well drained soil.

I know this is long, I apologize again, but I appreciate your careful review and answer in advance!

Thanks, and I can’t wait to hear your thoughts! Feel free to edit/ take snippets out for another FPSF blog post if it’s helpful. The post to end all FPSF/ slab prep/ frost blog posts! Honestly, 80 pages of blog post lists is very cumbersome. I’m thinking a digest of some kind is in order!

Mike the Pole Barn Guru responds:

Tune in to our next episode for a thrilling (and simple) conclusion!

This entry was posted in Concrete, Footings, Insulation, Pole Barn Questions, Pole Barn Design, Pole Barn Planning, Pole Barn Structure and tagged radiant heat, FPSF, pex tubing, skirtboard, insulation, vapor barrier on February 13, 2019 by admin.

How to Reduce Condensation in Post Frame Buildings

Condensation occurs when excessive atmospheric water vapor comes into contact with a cold surface. Post frame building condensation will be particularly common in winter time, in regions where temperatures reach dramatic lows, and also in spring and early summer when ground temperatures are still cool but humidity increases. Post frame building condensation can be a serious problem, as excess moisture can create an uncomfortable environment and even contribute to mold and mildew growth.

Heat Building

For condensation to build up, temperature of building floors, wall and other solid surfaces must be lower than dew point (temperature where water condenses). So if you want to keep condensation away, maintain a warm post frame building. Avoid using propane heaters, because combustion process creates water vapor. Electric heaters can effectively keep temperature and condensation under control.

Use Vapor Barriers

Vapor barriers can help to keep condensation under control if installed in right places. Ceiling level vapor barriers are a bad idea, because they keep water vapor trapped inside the building, rather than allowing it to exhaust through a continuous ridge vent. Wall vapor barriers, can prevent condensation from penetrating your building’s drywall and insulation. Look for an insulation product with a built-in vapor barrier (e.g. fiberglass batts with a kraft paper facing), or consider installing plastic vapor barrier sheets directly over your existing unfaced insulation.

Keep Water Out

If vehicles or equipment become covered in rain or snow, and you then park them in your post frame building, this added moisture can contribute to condensation. If you must park something wet inside, try drying it as best possible before moving it inside. Also, if you have water seeping into your post frame building from rain or snow melt, try installing a drain outside to keep water issues in check. Put simply, do not let water in.

Seal Floor

A garage floor coating, or epoxy, can help to dramatically reduce condensation by limiting water vapor passing through your building’s concrete slab.

Other Solutions

Remove anything from your post frame building containing or requiring water. This can include houseplants, drying laundry, and even bags of trash containing moisture. Installing continuous ridge vents (in combination with vented eave soffits) can also reduce condensation by drawing out warm moist air containing water vapor. In some cases, a dehumidifier can help to remove light to moderate condensation, because dehumidifiers are designed to attract stray water vapor onto specialized coils, trapping it and draining resulting liquid into a reservoir.

This entry was posted in Insulation, Pole Barn Design, Pole Building How To Guides, Pole Barn Planning, Pole Barn Structure, Ventilation and tagged electric heater, post frame building condensation, garage floor epoxy, vapor barrier, vinyl vapor barrier on February 5, 2019 by admin.

Reader Put Up a Competitor’s Shed

We Put Up a Competitor’s Shed

Sadly not everyone does adequate research to realize how outstanding of a value added a Hansen Pole Buildings’ post frame building kit package truly will be. Long time readers of these blog articles (nearly 1600) and questions answered in Monday’s “Ask the Pole Barn Guru™” column (around 1000) have come to understand most problems solved by me come from other people’s buildings.

How serious am I about our value:
I am offering to shop for you. Yes you heard me right. You give me up to three names of competitors to Hansen Buildings, where you can purchase a complete wood or steel framed pole building kit package, and I will shop them to get quotes for you.
Now I say three, because frankly, some people just are not very prompt or cooperative when it comes to getting back with price quotes.

Why would I do this? Comparing “apples to apples”, I know our price will beat theirs, every single time. I am doing this for your peace of mind. I guarantee other prices will be higher. And I will provide you with documentation to prove it!

There is a catch…..before I go shopping, you have to place your order for your new Hansen Pole Building kit….. subject to me “proving my point” by going shopping. Your payment to us will not be processed for ten calendar days. Within seven days of order, you’ll have competitive quotes in hand, or my documentation of having hounded them every week day for a week trying to get pricing for you (seriously, if you have to hound someone for a price, what kind of service will you get after they have your money?).

After I email you proof, if you seriously want to purchase from one of these competitors, just let me know before ten days from your investment and we tear everything up and go away friends.

Reader DAVE in ROBERTS apologizes for buying from a competitor and writes:
“Sir. Your blog has been most helpful. We put up a shed not one of yours but a competitor. (sorry). Shed size is 36×48. First mistake was we did not put a barrier under the concrete. Our plan now is R 19 in walls. One inch of foam plus R 39 in ceiling. I wired in two ceiling fans to move air with natural gas heat. Does this sound like a good formula, oh wise one?

Mike the Pole Barn Guru says:
Start by sealing your building’s concrete slab. This will be a possible solution: https://www.hansenpolebuildings.com/2018/11/siloxa-tek-8505-concrete-sealant/.

I am just not a fan of natural gas heat as it adds a tremendous volume of water vapor into your building. You’re going to have to find a way to exhaust all this water, else your building will have humidity issues.

Although now too late for you, there would have been alternatives: https://www.hansenpolebuildings.com/2016/12/modern-post-frame-buildings-geothermal/.

Let’s discuss your ceiling. I am hopeful you have trusses designed to support a ceiling load of five psf (pounds per square foot) or greater. Also hoping you have ventilation covered with enclosed vented eaves and a vented ridge. Unless you specifically asked for it, your building’s roof trusses probably do not have raised heels to allow for full insulation thickness above walls and in area closest to sidewalls.

Provided your trusses will support weight of gypsum wallboard, install any necessary framing to reduce drywall spans to two feet or less. Place 5/8” Type X sheetrock across bottom of ceiling framing. If you do not have a vapor barrier under your roof steel, spray two inches of closed cell foam insulation across the entire underside. Once you have paid for this, you will regret not having made other condensation prevention decisions.

While spraying foam – have it added to area closest to eave sidewalls (spraying onto top of ceiling drywall). Make certain to leave an inch of airspace minimum above foam, so air can flow in from eave vents. Foamed area should continue towards center of building until it reaches at least a six inch thickness. Balance of ceiling should have no less than R-45 and ideally R-60 of fiberglass insulation blown in.

For walls, I am hoping you have placed a Weather Resistant Barrier (WRB – like Tyvek) between framing and siding. If not, you have a couple of choices. You can remove wall steel from a wall, install a WRB and reinstall steel (repeat for each subsequent wall), or spray two inches of closed cell foam to inside of siding. Unless your building has full thickness bookshelf girts, install framing across inside of walls to eventually support wall finish (I recommend sheetrock). Fill entire insulation cavity with BIBs https://www.hansenpolebuildings.com/2011/11/bibs/.

Glue two inch thick closed cell rigid insulation panels to inside of wall framing, sealing all joints. Glue sheetrock to inside of insulation. Now you have a truly well insulated post frame building.

This entry was posted in Pole Barn Planning, Ventilation, Concrete, Sheds, Insulation, Pole Barn Questions, Pole Building Comparisons, Pole Building How To Guides and tagged R19 insulation, vapor barrier, natural gas heat, BIBS insulation, geothermal heat, Ventilation, closed cell insulation, post frame building kit package, vented ridge, Siloxa-Tek 8505 on January 15, 2019 by admin.

Slab Insulation, Vapor Barriers, and Sliding Doors

Today’s PBG addresses slab insulation, vapor barriers and sliding doors at an entry.

DEAR POLE BARN GURU: I am starting a project finishing a Hansen pole barn in a suburb of Minneapolis. My question is in regard to the floor. I assume there was no insulation under the slab, I have yet to confirm this, so how do I insulate after the fact? Are sleepers my only option?

Thank you for your time. CHRIS in MINNEAPOLIS

DEAR CHRIS: Whether before pouring slab or after, I’d go with a Frost-Protected Shallow Foundation https://www.hansenpolebuildings.com/2016/11/frost-protected-shallow-foundations/.

DEAR POLE BARN GURU: Contractors installed vapor barrier on the roof but not walls. What is the best way to install a vapor barrier now that the metal siding is up? JASON in ROCKVILLE

DEAR JASON: I usually recommend using a Weather Resistant Barrier between siding and wall framing (https://www.hansenpolebuildings.com/2016/01/determining-the-most-effective-building-weather-resistant-barrier-part-1/). Given where you are now – if chances of climate controlling your building are small, you can spray two or more inches of closed cell foam insulation. If you intend to heat you can entirely fill insulation cavity with unfaced fiberglass and then put clear visqueen on interior as a vapor barrier.

Dear Pole Barn Guru: I’m in the process of putting up a shop at my house. The front has a 20×12 opening and was planned to have sliding wood doors as the front will be bricked to match my house. Can you give me tips on how to effectively anchor this and will I need a backup door on the inside to seal out the elements? I don’t want big gaps so that animals and critters can easily make their way in. The building is in the middle of a bean field and it will have spray foam insulation. Thanks for the help! MICHAEL

DEAR MICHAEL: Sliding doors are not going to seal anywhere near air tight. How about going with an insulated carriage house style overhead door? It will give you a great look and be functional. Hansen Pole Buildings can provide a broad variety of carriage house doors with our complete post frame building packages. http://www.amarr.com/residential/garage_doors/carriage_house

This entry was posted in Steel Roofing & Siding, Ventilation, Sectional Doors, Post Frame Home, Insulation and tagged sliding doors, moisture barriers, slab insulation, carriage house doors, vapor barrier on December 11, 2018 by admin.

Pole Barn Moisture Issues

Moisture from condensation can be a major issue in initially poorly thought out pole barns.

Reader MATT in SHAKOPEE writes:

“Hi. I am having issues with moisture in my pole barn. It is getting to the point that mold is starting to show up on the walls and cement floor. The barn is about 28 x 36 with 12 foot walls. It has a service door and two 10 foot over head doors and 4 windows on the south wall. The ceiling is tinned, insulated and has a vapor barrier. The floor is cemented and I am unsure if the floor has a vapor barrier. The walls are not insulated or tinned.

The barn is used for storage right now cars, mowers, tractor, etc. The barn is unheated and sometimes the doors stay shut for one to two weeks. We have gone through and cleaned what seems to be mold off the walls but are unsure on how to stop the moisture issue. Wonder if some kind of exhaust fan would help? Or if you have any suggestions? Any help would be greatly appreciated.”

Mike the Pole Barn Guru writes:

I’d start with trying to eliminate moisture source. If you leave a wrench lying upon your building’s concrete floor for a few days and return and a dark spot appears below where the wrench was placed, your building has no under slab vapor barrier. If this occurs, use a good concrete sealant across floor. This in itself might resolve problems – watch the steel wall siding insides and see if they stay dry after sealing.

If this does not resolve problems, then you need ventilation. I will surmise your building does not have enclosed vented soffits and a vented ridge. Can’t go back and correct lack of overhang issues now, but you can add gable vents – a minimum of 242 square inches net free ventilation area in each endwall with vents located in top half of each gable.

Location of your building should also be examined. If soil around building exhibits signs of being moist, you need to make sure grade will allow water to drain away from building. It may be necessary to trench around building and add a drainage system to move water away from your building. Gutters should drain water sufficiently distant from building as well.

If nothing else works, here’s how to determine power ventilation requirements: https://www.hansenpolebuildings.com/2018/07/my-pole-barn-needs-ventilation/.

This entry was posted in Ventilation, Concrete, Pole Barn Questions, Pole Barn Planning and tagged vapor barrier, condensation, mold, moisture issues, insulation on October 24, 2018 by admin.

Cold Storage Pole Barns

Post Frame Cold Storage for Fruits and Vegetables

Hansen Pole Buildings’ Designer Rachel passed along this:

“Have a client call in asking if we have experience in designing a building for cold storage. Confused I said yes, many building are used for cold storage and are not insulated or heated. He said no I mean COLD storage as in storing fruits and vegetables in 36 or 38 degrees. He is wondering what we would suggest for insulation and what he should consider when designing the building.”

Detached cold storage buildings are constructed with a sole purpose of producing or storing goods in low temperatures. Think of them as typical heated buildings turned inside out. Instead of keeping heat in during cold weather, they keep heat out during warm weather.

Condensation problems can be huge, if not properly dealt with. Adequate and totally sealed insulation plays a huge part in preventing condensation. Exterior walls should have a Weather Resistant Barrier between framing and wall steel to allow moisture to pass out of wall. Dead attic spaces should be well ventilated with eave air intakes and ridge exhaust vents.

Among most critical consideration for cold storage will be selection of a method for insulating the facility. Effective insulation will minimize cold transfer to exterior and reduce operating costs. Recommended cold storage building envelope (shell) insulation values are R-30 in walls and R-40 for roof. Concrete slab should be insulated to R-20. Recommended method of insulation will be polyisocyanurate (Polyiso). Polyiso has an R value of approximately six to 6.5 per inch of insulation, so a minimum of five inches of Polyiso recommended for walls and 6 ½ to 7” in ceiling. It should be glued on, as through fasteners will transmit heat and condensation could form upon exposed heads. It is essential for joints to be sealed and a vapor barrier should be placed between insulation (insulation goes inside of framing) and wall girts and ceiling joists.

Failure to totally seal interior vapor barrier can result in Polyiso insulation gaining as much as 15 times its own weight from absorbed moisture.

Special consideration needs to be given to site preparation, in order to minimize possibility of frost heave.

Building access should be through a wide 14 foot tall insulated overhead door in each endwall. Industry standard storage bins are four feet square and three feet tall. Bins can be stacked five high, leaving room for mechanical equipment above with a 20 foot interior clear height.

Allowing space for equipment movement and free airflow around each stack of pallet bins approximately 215 pounds of product can be effectively stored for every interior square foot of building.

And there you have it…a cold pole barn!

This entry was posted in Pole Barn Planning, Ventilation, Insulation, Pole Barn Questions, Pole Barn Design and tagged insulation, vapor barrier, condensation, polyiso, polisocyanurate, cold storage pole barn, post frame cold storage on September 20, 2018 by admin.

My Pole Barn Needs Ventilation

My Pole Barn is a Sauna in Summer- and needs ventilation!

“Hey there Pole Barn Guru, got a question about ventilation.

Just bought a house with a pole barn on the property. I believe it’s only about a year old. 30 x 32. It has no soffits or windows, only a standard garage door and walk-in door.

Metal siding and roof, and the underbelly of the roof has a vapor barrier. There are also two ceiling fans in here.

I don’t care that it’s cold inside the building in winter, but it’s like a sauna now in the summer. I was thinking of an exhaust fan to pull out the heat, but I don’t know if that’s waste of money. How does one ventilate this thing without having to bulldoze it and start over?

Thanks.

Dezy”

Mike the Pole Barn Guru responds:

Since you cannot increase the amount of venting in your soffits (as you have none), you’ll need help from power vent fans.

Attic vent fans can be hard-wired and equipped with a thermostat and/or humidity sensor so they automatically cut on at a preset moisture level or temperature. You could also install solar-powered attic vent fans, though it has been found most solar models aren’t powerful enough to be very effective.

To determine what size power vent fan(s) you need for your attic, you first need to know the size of your attic in square feet.

Attic Size

To determine the size of your attic, multiply the width by the length of the attic floor in feet. In your case 30′ wide x 32′ long = 960 square feet of attic space.

Vent Fan Size

Next, multiply the square feet of attic space by 0.7 to get the minimum number of cubic feet of air per minute the fan should be rated to move. 960 sft x 0.7 = 672 CFM minimum fan rating.

Add an additional 20% (CFM x 1.20) if you have a steep roof, and 15% (CFM x 1.15) for a dark roof. Attic vent fans are commonly rated from 800 to 1,600 CFM, making one fan suitable.

Vent Fan Location

Install gable mounted fans on the gable vent at end of the building facing away from the prevailing winds.

Intake Air Vents

It’s also important to have plenty of soffit or gable vents for the fan to draw air into the attic. To find out if you have enough vent space, divide the cubic feet of air per minute the fan(s) is rated for by 300 to come up with the minimum number of square feet of intake vent space needed for that size fan. 672 CFM ÷ 300 = 2.24 sq. ft. intake vent area

If you prefer the answer in square inches rather than square feet, multiply the answer by 144 and round to the nearest inch (2.24 x 144 = 322.56 sq. in. vent area).

This entry was posted in Ventilation, Pole Barn Questions, Pole Building How To Guides and tagged gable vents, attic ventilation, attic vents, power vent fan, attic vent fan, CFM, vapor barrier on July 9, 2018 by admin.

Isolating Pole Barn Poles from Concrete Slabs

Isolating Pole Barn Poles From Concrete Slabs

The fear factor – comes up again and again in construction. Today’s fear is a concrete slab being poured against the poles (columns) of an existing pole barn will cause the columns to decay.

“We have a 25 year old pole barn with 12 main 8×8 poles sunk 8 feet into the ground.

We’d like to pour a concrete slab under the entire building (as it is dirt now).

I was just going to pour the concrete right up to, and around, the poles, but some folks have me thinking that the concrete directly on the wood will create a lot of condensation and moisture and eventually rot/weaken the poles right at the floor.

I hear of people using styrofoam or expansion joint felt as a wrapping for their poles, but all of those discussions relate to avoiding cracks in the concrete from pole movement. My concern is for the poles themselves.

What is an appropriate barrier material to clad the bare poles in, and then pour concrete right up to, that will prevent moisture from collecting on the poles themselves?

Yes, we will be doing a vapor barrier under the concrete – but there will be 12 8×8 holes punched into that vapor barrier which could allow moisture up right into the part of the concrete pad that we don’t want it – the part touching the poles…

All comments and suggestions appreciated.”

Mike the Pole Barn Guru responds:

Properly pressure preservative treated wooden timbers are not only designed to be buried in the ground (with the proper level of pressure treatment being UC-4B), but also are required by Code in cases where wood is in contact with concrete.

So, how is it concrete would cause condensation against the pressure treated wood? Concrete retains a significant amount of interstitial moisture for many years. This moisture routinely moves in and out of a vapor phase, depending on the temperature and relative humidity. Placing anything which is reasonably “barrier like” to moisture (which wood is for the short term) can cause moisture to collect under the material in a liquid phase. This is one reason the wood needs to be pressure treated.

Another reason for the wood to be pressure treated is concrete is aggressively alkaline. In the absence of pressure treating (usually acidic), the wood will dry out and its cell structure will be damaged from the exposure to the drying/alkaline condition.

The reality is there is really no reason to isolate the pressure treated columns from the concrete slab.

Other than fear (False Expectations About Reality).

For more reading on longevity of pressure preservative treated lumber, please read: https://www.hansenpolebuildings.com/2017/12/will-poles-rot-off/.

This entry was posted in Pole Barn Structure, Concrete, Columns, Insulation, Pole Barn Questions, Pole Barn Planning and tagged vapor barrier, pressure treated wood, post frame columns, expansion joint felt, vapor barrier under concrete slab on July 5, 2018 by admin.

Pole Barn Insulation, Oh So Confusing

How to best insulate any building can be confusing – with pole barns being right there with any other structural system. “Best” also has to include a balance between the upfront investment and the long term savings, throwing in the wild guess as to what future costs of heating and/or cooling might be. Energy costs are probably not going to get any less expensive, so using today’s costs in determination of the outcome should yield a conservative answer.

To me – a practical return is if I can have my investment returned within a seven year period or not. There are also some intangibles to be factored in, such as a well-insulated building being much quieter for the occupants.

Regular readers will recognize the volume of questions I receive from those who did not plan ahead for the eventuality of climate control and are now looking for solutions. This is an issue which can and should be economically planned for at time of construction.

Reader MATT in ROCKFORD got the ball rolling on this subject when he wrote:

“I am ready to build my dream garage but somehow I managed once again to stumble upon an area where people just can’t agree on a single solution. Insulation!!! There should be a single answer for each barn use. 1: Storage only use this… 2: Equine only use this… 3: Workshop/Garage with occasional winter heat use this… 4: Garage/Mancave/House with full time HVAC use this… Plus the difference is argued about whether to use a radiant barrier? Or vapor barrier and where to put them. Vapor barrier like Tyvek etc. outside, plastic vapor barrier inside between wall material and the studs. Up north, snow on steel. Down south sun blazing on the steel. To vent or not to vent is also important.

I would like to have a person with proper insulation experience in the north and the south who can explain why and in which order ( pic or graphics would be fantastic ) of what is correct. And give definitive answers boasting absolute confidence instead of having an answer that seems wishy-washy. Many kit distributors like to sell things easy to ship (dbl bubble radiant barrier). Many builders like speed, convenience, and mark-up (radiant barrier). Seems like spray foam has issues too.

Ultimately I live in Alabama where humidity, mold, and insects are a definite issue. I am building my final dream garage/home and I am disabled with a limited income so I can’t afford to make a mistake.

Ugh Please Help!

I also forgot to mention or ask about insulation that follows the roof line like in a clearspan structure. Or using steel trusses or scissor trusses where the insulation may be next to the roof and there is no attic. Thanks, Matt”

Matt ~

I feel your pain. Insulation and ventilation are areas where there are a nearly innumerable number of possible solutions, many of which both work and can be Code conforming. Over my nearly 40 years in the post frame building industry, my own feelings about how to properly insulate have changed – most due to the advent of new products, better research and the gaining focus on energy efficiencies.

Tune in tomorrow for the rest of the story!

This entry was posted in Insulation, Pole Barn Questions, Pole Barn Planning and tagged vapor barrier, scissor trusses, radiant barrier, climate control, double bubble radiant barrier on June 14, 2018 by admin.

The Drip, Drip, Drip of Condensation

Reader JIM in HOODSPORT writes about condensation issues:

“New Completed 40’ x 60’ pole barn with 16’ side walls and 24’ peak. Walls and ceiling insulated, 60’ long ridge roof vent. Full cement Pad with plastic vapor barrier under it. Cement was 60 days old when barn was completed.. rained just about every day. No windows or vents, using for RV storage and Shop. 2 – 12’x14’ roll up doors. 1 entry door. Will eventually have some sort of heat and ceiling fans installed.

Live in Hoodsport, Wa. Very near Olympic Mtns.

Issue is that the barn does not want to dry out … getting condensation on ceiling insulation…had contractor come out and clear out excess insulation that may have been blocking vent and make sure ridge is secure and no blowing rain can get in….had entire roof check for holes…

Still dripping..thought the vent and insulation would take care of the issue?

Afraid if I start putting vents all over the place I would be wasting the heat while I work in shop.

On a warm day should I open doors and get large fans and vent area of excess moisture? Get heaters in to dry out? Don’t propane heaters put moisture in the air?

Please Help…”

The short term solution is to open up the overhead doors and leave them open until it dries out.

Why you have the problem – your concrete floor is poured over a vapor barrier (excellent choice), however it does not allow any moisture to escape into the ground. You have a vented ridge, which will not work as it needs an air intake in order for air to escape from it. Your building should have had enclosed vented soffits – which would have allowed for airflow in at the eaves and out at the ridge.

Now – let us address the bigger and long term problem – you want to heat this building. As it stands currently, you might as well just put a heater out in the yard and expect it to warm your building. The “insulation” you have is nothing more than a condensation control blanket – it has an R value right close to absolute zero every time it crosses a wall girt or roof purlin. If your plan is to try to take the chill off a bit for an hour or two using a space heater, then you might as well plug up the ridge vent, which isn’t working anyhow.

If you want to be able to do a decent job of heating, you have some work to do.

First, get an engineered repair to upgrade your roof trusses to support at least a five psf (pounds per square foot) ceiling load. This can be obtained at a nominal charge from the company which manufactured your trusses.

Second, remove all of the wall steel. Take off the condensation control blanket in the walls and throw it away.

Third, install enclosed soffits with level returns on the eave sides. This will entail having to shorten the wall steel and adding some framing. Now the ridge vent will actually work. Put housewrap (think Tyvek) on all of the walls and reinstall the wall steel.

Fourth, after repairing the trusses, install ceiling joists between the trusses (2×6 #2 every 24 inches with joist hangers), install 5/8″ drywall on the underside and then blow in 15-20 inches of fiberglass insulation, making sure to allow at least an inch, if not two, of clear air flow at the eaves so you do not block the vents. This will mean a lesser R value at the sidewalls. You could have four inches of spray foam insulation placed on top of the drywall in the two feet closest to each sidewall, which would help.

Lastly the walls – fill the insulation cavity completely with unfaced insulation, cover with 6 mil clear visqueen, then gypsum wallboard.

Oh, another sidebar, please check the engineered truss drawings for your building – there may be some truss web bracing which is missing, most likely on the diagonal webs going up from the bottom chord at the center of the trusses.

This entry was posted in Pole Barn Questions, Pole Barn Design, Building Overhangs, Ventilation and tagged vapor barrier, tyvek, vented ridge, enclosed vented soffits, condensation control blanket on May 17, 2018 by admin.

How to Install Fiberglass Batt Insulation

How to Install Fiberglass Batt Insulation in a Post Frame Building Attic
There are times when I overlook things which seem obvious to me, but do not appear to be so to the innocent beginner doing their own construction work. This past week we were contacted by one of our new post frame building kit owners, who had hired a contractor to assemble his building. The contractor was apparently facing some challenges when it came to installing the unfaced fiberglass insulation batts in the attic space.

First step – unless your post frame building has trusses spaced every two feet, chances are good the ceiling joists must be installed between the truss bottom chords.

Exception (and not covered in this article) would be if your building is going to use steel liner panels for a ceiling and the trusses are spaced appropriately to be able to support the liner.

Step two is to install the ceiling material, which in most cases is going to be 5/8” sheetrock (although other materials such as OSB or plywood could be used). Do not install a vapor barrier between the ceiling materials and the ceiling framing.

Step three – lay down boards or plywood sheeting to help you be able to walk safely in the attic space.
When installing fiberglass insulation, observe all safety precautions. Fiberglass can release tiny fibers, which can be harmful if breathed into the lungs and which may irritate the skin. Wear protective gear.

The necessary R-value for the attic will depend upon the manufacturer and style of insulation chosen. Check with the manufacturer’s instructions on the packaging to determine how much insulation thickness is needed to achieve the desired R-value.

Once you’ve determined the amount and type of insulation needed, and the insulation has been purchased, begin staging the rolls in the attic. Place rolls around the perimeter of the attic for easier access during the installation.

Fourth – When laying insulation, it’s a common mistake to cover up the soffit vents. Soffits are part of the overall ventilation scheme, and covering them blocks essential air flow in the attic. With the widely spaced trusses typical of post frame construction, insulation baffles can be created by using rigid insulation boards to maintain a minimum two inch airflow above any insulation.

Fifth – Begin laying in the insulation, starting at an area furthest from the attic access.
When rolling the insulation, cut it to length using a utility knife.

When you reach the end of a line, pull the insulation back slightly, then place it on a joist so there is a solid surface to cut on. Using a straightedge as a guide, make your cut.
After making the first cut, use the remaining portion of the roll and work back in the other direction. When you reach the end of the roll, butt a new roll up to the cut piece and finish the run.

Once the perimeter is reached, cut the end of the roll to fit. Using this technique results in the best use of the insulation and reduces wasted material.
Lay the rows snugly together to prevent undesirable gaps or spacing.
When you run into an obstacle like a cross-brace or pipe, cut a notch in the insulation roll to fit around the obstacle, then continue with the run.

Areas around the perimeter of some attics can be rather tight and confining. Just keep rolling out the insulation, but don’t compress or squeeze it into tight spots, as this can decrease the insulation value.

This entry was posted in Insulation, Pole Building How To Guides, Trusses, Building Interior and tagged ceiling joists, vapor barrier, insulation R value, post frame building kit on February 16, 2018 by admin.

Building a Pole Barn House

Reader JEREMY writes:
“Good Morning and Happy New Year!
We are currently in the process of building a house inside a pole barn, and have noticed condensation on the inside walls and roof when we heat it. We do not have any vents installed yet, and would like to know if the condensation will stop after we get the walls/insulation/sheetrock put up and vents added to the attic. We are very concerned about this issue, so any advice you can give will be greatly appreciated by our family J!

enclosed overhangs Here are a few details about our current building:
-No vents to the outside yet, but plan to install venting in the attic soon.
-Regular R-panel metal roof and walls installed on wood runners hanging on treated wood posts.
-Concrete slab floor that has been poured for about 2 years
-Bubble wrap insulation between metal outside and wood runners-not sure of r-value or details and it seems to be sealed well
-When heating we are using an old propane central heating unit, but did not have exhaust on the heater ran to the outside so thinking that could contribute to the condensation
-also use a wood stove to supplement heat when we are out in the building working
Let me know what you think when you have time, and thank you!”
Jeremy ~

Mike the Pole Barn Guru

My first guess is there is not a well sealed vapor barrier under your concrete slab. if not, things which will help – make sure ground around your building is sloped away at at least a 5% slope for 10 feet or more. If you do not have gutters, get them. Have downspouts discharge at least 10 feet away from the building. If excess water is still present, it may be necessary to install drain tiles around the perimeter of your building.

If you have not insulated the perimeter of the slab, do so. Follow the guide for Frost-Protected Shallow Foundations (https://www.hansenpolebuildings.com/2016/11/frost-protected-shallow-foundations/).

Seal the surface of the concrete slab.

Take off the steel siding, remove the reflective radiant barrier from the walls and install a quality building wrap (like Tyvek), then put the siding back on. The barrier is keeping moisture in your building, whereas a building wrap allows moisture to exit. Completely fill the wall cavities with insulation. Place a well sealed vapor barrier between framing and gypsum wallboard to be installed on the walls. Do not place a vapor barrier between the ceiling drywall and the roof framing above.

Install fully vented soffit panels along the eave sides and a continuous ridge vent.

This entry was posted in Building Interior, Insulation, Pole Barn Questions, Pole Barn Homes, Pole Barn Design, Pole Building How To Guides, Pole Barn Planning, Ventilation and tagged frost protected shallow foundations, pole barn house heating, vapor barrier, condensation, downspouts, rain gutters on February 6, 2018 by admin.

A Retro-Fit, Truss Support? and Sliding Door Installation

The pole barn Guru looks at a Retro-Fit, truss supports, and installing a sliding door.

DEAR POLE BARN GURU: I have a question about Retro-Fit insulating my pole barn. I live in Southwest Michigan and bought my house with an existing 40’x60′ building, just used for storing farm equipment before I acquired it. Steel roofing straight to the roof purlins and steel siding straight to the wall purlins. Can I put a metal ceiling in with blown fiberglass insulation above and metal walls with Batts between the inside wall and outside wall, or do I need to have some sort of vapor barrier? MITCH in MICHIGAN

DEAR MITCH: First things first, in order to retro-fit the trusses, confirm the trusses are capable of supporting the weight of the steel liner panels and insulation. Most post frame building trusses are not designed to support a ceiling. There should be a stamp on every truss which identifies the truss manufacturer as well as the design loads. You need a minimum three psf (pounds per square foot) bottom chord load to support the ceiling. If it is less, and you can contact the truss manufacturer who should be able to provide an engineered repair to upgrade the trusses, for a nominal fee.

You will need to have some form of thermal break below the roof steel – my choice would be closed cell spray foam. On the walls, you should really have a building wrap between the steel and the framing, however an inch or so of closed cell spray foam would work, filling the balance of the cavity with unfaced fiberglass, then a well sealed vapor barrier on the inside.

DEAR POLE BARN GURU: Pole Barn Guru, do you have to have girt under end trusses. End trusses setting on 2×12 from header and nailed to 6×6 pole with 2×6 blocking below trusses 24″o.c. sheated header 3 2×12 notch blocked and clipped. STEVE in CHEYENNE

DEAR STEVE: In order for me to answer your question, I would need to see the engineered plans for your building. If you are unsure of how to determine from your plans, you could contact the engineer of record who designed your building and ask him or her.

DEAR POLE BARN GURU: On a sliding 4×8 walk in door, on the barn exterior are all 4 sides flat or is the top out the thickness of say 1.5 inches? If it is out will it not seal? If all is flush with it not roll easy? Joe

Figure 27-5

DEAR JOE: The sliding door track needs to be mounted to a ‘track board’ which is typically a 2×6 placed on the face of the sliding door header. This puts the top out 1-1/2″ which allows the door to be able to slide past the adjacent siding without banging against it. Sliding doors do not and will not seal air tight, so this should not be an issue unless you had some sort of unrealistic expectations.

This entry was posted in Sliding Doors, Pole Building Doors, Trusses, Professional Engineer, Insulation, Roofing Materials, Steel Roofing & Siding and tagged truss repair, engineer, sliding door, Plans, Framing, Retro-fit insulation, vapor barrier, Roof dead loads on January 22, 2018 by admin.

Tear Down to Rebuild? Bay Spacing, and Condensation Problems

DEAR POLE BARN GURU: Hello, I am going to tear down a 30x40x10 pole building to rebuild on my property. I noticed that the trusses are spaced 10 feet apart and are set on the 6×6 pole that has been notched. With no header board. This is an all metal building. Was wondering if this is an acceptable method of notching the post to put trusses on. Thanks. SHAWN in INDUSTRY

DEAR SHAWN: The most typical engineered post frame design provided by Hansen Pole Buildings utilizes a double (two ply) prefabricated wood truss notched into the columns (most usually spaced every 12 feet). This, in my humble opinion, is a combination which provides the best possible truss to column connection for post frame buildings, along with the reliability of the double truss system.

I would have concerns about the reassembly of a tear down, due to possible materials damage, as well as the building possibly having been designed to a no longer valid building code. My recommendation would be to contact the original engineer of record for advice as to how to proceed. If you are unable to contact him or her, then a local RDP (Registered Design Professional – architect or engineer) should be engaged to determine the structural integrity of the building as well as its adequacy to support the given climactic loads under the current building code.

DEAR POLE BARN GURU: Hello again! I reread the instructions and it said for immediate response to leave email. So I posted it above. Hello Pole Barn Guru! Wishing you a blessed day. My question is about a studded wall with double trusses. What I am trying to do is avoid having to build a 14 ft wall to accommodate a car lift. I am building a 30×50 shop. The garage doors will be on the 50 side. My thinking is build stud walls and frame in laminated posts to resemble a 6×6. They would be set at 10 widths to accommodate a 10×10 garage door. This way I could set the trusses and have open overhead bays between the trusses to accommodate the car lift and not have to build 14 ft walls. Would the idea of double trusses work in this type of build? TONY in ATHENS

DEAR TONY: If you are starting from scratch, why not just construct an engineered post frame building and columns and double trusses approximately every ten feet? I say approximately as a 10 foot width residential overhead door requires roughly 10’1″ of width between the columns. We can design a building for you, which would not have bottom chord bracing between the trusses in the bay where the overhead door would fall – thus allowing for extra headroom for your car lift. You will certainly get the most for your building investment by using post frame design.

In the event you are already constructing some other sort of building, you should consult with the Registered Design Professional (RDP – registered architect or engineer) who designed your building, as he or she would need to make the appropriate alterations to ensure the structural adequacy of what you have in mind.

In any case, for the sake of safety, do not attempt to do design work on your own – entrust it to a RDP.

DEAR POLE BARN GURU: I have a pole barn in Colo Springs. I have pretty bad ceiling condensation in the winter. The prior owner just stuck R-36 up there. I am thinking of removing each roof panel and putting Rufco Vapor Barrier and putting the metal roof panels back down.

I would prefer to do it inside with a radiant barrier but that will probably not work. Any suggestions? Something better than Rufco? Thank you. FRANK in COLORADO SPRINGS

DEAR FRANK: On your existing building – while Rufco is an excellent vapor barrier, it will not stop condensation issues, as it does not provide a thermal break. If the prior owner installed the batt insulation in the plane of the ceiling, I would recommend the use of closed cell spray foam on the underside of the roof steel. This would eliminate having to remove and reinstall the roof panels. If this is your only option, Hansen Pole Buildings does provide a reflective radiant barrier in six foot net coverage widths with a tab on one side with an adhesive pull strip for easy sealing of laps. You might give this a consideration.

This entry was posted in Ventilation, Rebuilding Structures, Sectional Doors, Uncategorized, Insulation, Roofing Materials, Pole Barn Planning and tagged tear down, bay spacing, auto lift, car lift, rebuild, vapor barrier, A1V insulation, condensation on January 1, 2018 by admin.

A Stone Base Floor? Trusses vs Rafters, and Entry Door Install

DEAR POLE BARN GURU: I have a 40 x 24 pole barn with a 4 inch stone base floor. Can I place 2×4 grid framing 24 in on center with 3/4 inch T&G 4 x 8 sheets for light weight shop usage? No vehicles. JEFF in SYCAMORE

DEAR JEFF: Some ifs – if your site is drained so as to not have excess moisture beneath the building, if the subgrade is thoroughly compacted and if you have a well-sealed vapor barrier underneath, then it might work. Be prepared for the possibility of frost heaving. Both the framing and the sheathing should be pressure preservative treated to a minimum UC-4B level to prevent possible deterioration.

DEAR POLE BARN GURU: You compare scissor trusses to conventional trusses, but I see nothing about using beams instead. I’m aware of only one post frame supplier that provides beam systems in lieu of trusses. Are there any down sides to using beams and avoiding trusses all together? RACHEL in ST. LOUIS

DEAR RACHEL: My only guess would be you mean rafters, not beams. Or it could be your intent is a ridge beam supporting rafters. In any case, the answer is going to come down to time, money and reliability. If an alternate system to prefabricated wood roof trusses is to be used, it should most certainly be a design which has been thoroughly reviewed and sealed by a Registered Professional Engineer. Obviously prefabricated wood roof trusses are most highly prevalent because they offer the advantages without the expense of time and labor.

DEAR POLE BARN GURU: Can I install a 36″ steel entrance door before the exterior girts are applied? DONAVON in EAGLE GROVE

DEAR DONAVON: In most cases, the columns on one or both sides of the entry door are trimmed off above the door and supported by a wall girt which runs between two roof supporting columns. If your particular application has framing on both sides of the door which is attached to the roof system, then it would probably be possible to install the entry door prior to the wall girts. I am not seeing any apparent advantage to doing so and it would add to the possibility of inadvertent damage to the door.

This entry was posted in Pole Barn Design, Pole Barn Structure, Pole Building Doors, Trusses and tagged Rafters, Framing, Entry doors, trusses, vapor barrier, Stone floor on December 25, 2017 by admin.

Condensation Solutions, A Ceiling the Right Way, and Timing

Advice about condensation, ceilings done right, and the timing of questions

DEAR POLE BARN GURU: My deck roof is metal panels on 2×4 purlins, rafters are 2×6, like a pole barn. I am enclosing it, and need to stop the condensation. I spray foamed it with closed cell, but there is some condensation on the foam in a few places. It will be covered with drywall. Would a 6 mil plastic vapor barrier on the conditioned side work? MICHAEL in FRAZIER’S BOTTOM

DEAR MICHAEL: Provided you are able to reduce the moisture content within the building so as no vapor is being trapped between the vapor barrier and the foam, it should take care of the problem. In all reality, as long as you have no holes in the gypsum drywall, once it is painted you should have eliminated the problem of condensation against the insulation.

Now getting to the real problem – you have too much moisture in your building. If you did not place a well sealed vapor barrier under your concrete slab floor, you need to seal it. Walls also need a vapor barrier (without holes) on the conditioned side to prevent moisture from passing through.

DEAR POLE BARN GURU: I have a 40 x 80 pole barn with 8 foot truss spacing. I will be installing faced rolled insulation between each truss. What is the recommended ceiling product to install on the inside? Wood, metal, that will be lightweight and easy to install?? Thanks JEFF in SYCAMORE

DEAR JEFF: I see problems in your future….

Faced insulation is the absolute wrong product to use for insulating your ceiling. Any insulation placed at the truss bottom chord level should be unfaced. The best bet would be to blow insulation in above the finished ceiling.

In any case, you must adequately vent the attic space.

Now, on to the ceiling.

I am hopeful you have trusses designed with a minimum of a five psf (pounds per square foot) ceiling load, with 10 psf being even better. Confirm with your RDP (Registered Design Professional – architect or engineer) who designed your building, however 2×4 #2 ceiling joists at 24 inches on center between the bottom chords with joist hangers should adequately support a ceiling.

My choice of ceiling product?

5/8” Type X gypsum wallboard. It is affordable, weighs under three psf and provides fire resistance.

DEAR POLE BARN GURU: I’m putting up a building with a 3/12 pitch single sloped roof. radiant reflective polyethylene, vapor barrier insulation between the purlins and the metal roof sheathing. Probably rock wool batts under the 1-3″ draped barrier. Do you think the roof has to be vented, and how would this work? CHRIS in BROOKLINE

DEAR CHRIS: Yes, it would need to be vented and it is my feeling you are going about this entirely in the wrong direction. Your question is well timed, as I have just written an article on how to properly insulate between purlins, which will be posted soon. The basic gist is your best solution is to use closed cell spray foam applied directly to the underside of the roof steel.

This entry was posted in Insulation, Pole Barn Planning, Trusses, Ventilation and tagged spray foam insulation, barriers, ceiling joists, vapor barrier, condensation, truss loads on December 18, 2017 by admin.

Post Frame Insulation in the South

Post Frame Insulation in the Hot and Humid South

Reader RICK in LUCEDALE writes: “Dear Pole Barn Guru, I am in the planning stage for designing a post frame house. I live in a “Hot and Humid” climate in the southern US. Joseph Lstiburek, a building science guru, suggests having an unvented roof for my climate zone with the HVAC in the conditioned air space. The metal roof would have a layer of single bubble vapor barrier under it with BIBS insulation installed in the roof purlins. The walls would have a building wrap behind the metal siding and BIBS insulation. The walls would have a vapor barrier between the drywall interior and the insulation. Does the roof assembly need another vapor barrier on the inside? What happens at the intersections between the single layer bubble vapor barrier, the building wrap, and the sub slab vapor barrier? I assume I can use non venting closure strips at the ridge and closed non venting soffits? What size should the purlin be to get an R value of 30+ ? What would be your recommendations? Thanks.”

Mike the Pole Barn Guru writes:

Unless your post frame house will have extremely large purlins, you will not be able to get sufficient depth of insulation using BIBs. Energystar.gov recommends roof insulation values of R-30 to R-60 for your part of the country. BIBs provides an R value of 4.23 per inch, so to achieve a minimal value of R-30 would require at least a 2×8 purlin and would realistically not provide the insulation value I would personally be looking for.

I’d be looking at the use of closed cell spray foam insulation, which would give you R-7 or better per inch of depth. It also completely seals everything, eliminating the need for a reflective barrier below the roof steel. With 2×6 purlins, one could spray eight inches of foam completely filling the space between the purlins as well as covering the underside of them (and the underside of the roof truss top chords).

The goal here is to achieve a complete envelope seal of your building’s perimeter. You will not want a vapor barrier between the living space and the attic. The building wrap is not a vapor barrier, it is a weather barrier. The vapor barrier on the inside of the walls should be installed so as to be sealed into the roof plane spray foam and sealed tightly to the slab on grade (although I prefer living over a crawl space).

Soffits should be non-ventilated and closed cell foam closure strips should be used at the top and bottom of all steel panels.

This entry was posted in Ventilation, Insulation, Pole Barn Questions, Pole Barn Design, Pole Barn Planning and tagged spray foam insulation, vented roof, energystar, vapor barrier, BIBS insulation on September 20, 2017 by admin.

Post Frame Antiperspirant- Ventilation Frustration

This is a sad story I hear all too often from pole (post frame) building owners who have buildings which were not properly designed for future uses, especially when it comes to insulation and ventilation.

Reader JASON in TENINO writes:

Hi Pole Barn Guru,

I recently purchased a new house and it came with a 40×60 shop. This past year I’ve experienced terrible slab sweating every time there is a change in humidity. Now that it’s summer I would like to prevent the sweating from occurring again. What are my best options on a limited budget? I’ve looked into using a penetrating concrete sealer, but I don’t think that addresses the underlying condensation problem.

As far as I can tell the shop has no ventilation of any kind (ridge/gable/soffit). And I’m noticing black mold starting to develop in the insulation below the roof. And I’m not sure if any sort of vapor barrier was placed before the slab was poured.

In the future I would like to insulate and heat the shop, but for now, I’d be happy if I can stop my condensation problems.

Thank you for your help!!!

DEAR JASON:

Yep – you have a problem on your hands. I can pretty much guarantee there is no vapor barrier under your concrete floor, which is a shame someone cheaped out. Vapor barriers are so inexpensive.

Taking care of first things first, let’s get the floor sealed. Here is the information you will need: https://www.hansenpolebuildings.com/2012/07/concrete-sealer/.

Secondly – get rid of the mold. Mix in the ratio of one cup bleach per gallon of water and use a hand pump sprayer to saturate all moldy surfaces. You can also use a scrub brush to remove the existing mold.

Third – I am going to leap ahead to your future plans, as they will impact your solutions now. I am not a gambling man, but I would put money on your shop’s trusses not having been designed to support the weight of a ceiling. This means if you want to eventually insulate and heat the building, you will have to insulate above the bottom chord of the trusses and up the roof line. On the walls, you can frame in either with a stud wall or with bookshelf girts to create a method to support insulation, with either batts or BIBs (Blow in Blanket) insulation being the most cost efficient and effective for your investment dollars.

Insulating the roof, not so easy, as the only really practical solution will be to use closed cell spray foam between the roof purlins. You will want to consult with an installer to get their opinion as to whether the metal building insulation under the roof steel will have to be removed prior to spraying.

If you are going to spray foam, then you do not want to use a ridge vent, as the foam would cover it.

Here is my best advice (provided you have the space on your property) – use your existing building only for cold storage. Since you do not have vented sidewall overhangs to create an air intake, the only solution for ventilation is to use large vents in each endwall. At a bare minimum, you should have at least 576 square inches on net free flowing vent in each end – located in the top half of the gables. You may need to add power vents, in order to adequately move the moisture out of the building.

When your budget allows for some climate controlled space, construct a new building which is properly designed to be able to be energy efficient.

Here is a short list of features which you should include:

Underslab vapor barrier
Pex tubing in slab for in floor heat
Perimeter slab insulation (rigid foam)
Bookshelf wall girts to create an insulation cavity
Housewrap between wall girts and siding
Vented sidewall overhangs
Ceiling loaded trusses with ceiling joists
Raised heel trusses to allow full insulation depth from wall to wall
Blow in R-45 to 60 of ceiling insulation
Reflective radiant barrier between purlins and roof steel

Good luck and let me know how things turn out!

Mike the Pole Barn Guru

This entry was posted in Insulation, Workshop Buildings, Pole Barn Questions, Pole Barn Design, Building Overhangs, Pole Building How To Guides, Pole Barn Planning, Ventilation and tagged Ventilation, ceiling insulation, how to get rid of mold, reflective radiant barrier, vapor barrier, BIBS insulation on August 11, 2017 by admin.

Converting a Pole Barn to a Residence

One trend I have seen over the past ten years is folks purposefully designing post frame buildings to homes – they are recognizing the advantages, among them savings in foundation costs, speed of construction, flexibility of design and ability to insulate. Along with this, more and more post frame buildings are being re-purposed from pole barns to living spaces. This becomes a challenge when advance thought was not put into the original building design as to what future uses might bring.

Reader MARK from FOSTER is in the midst of wanting to do one of these conversions and he writes:

“DEAR POLE BARN GURU: I have a pole barn that has foil bubble wrap on both roof and wide walls. I’m wanting to convert this into living space. I have 7″ of space in the walls to put insulation. So to insulate this can I add un-faced batt insulation and then drywall. I know that the foil-bubble wrap is waterproof so I don’t think I need a vapor barrier before the drywall because if any moisture was able to get in, it would not be able to get out. For the ceiling do I add Faced Batts with the facing point towards the heated space and then Drywall. You are the Guru and I want to see what your experience has to say. Thanks for your time.”

DEAR MARK: As a living space, your pole barn (post frame building) will generate a significant amount of moisture which you do not want to have get into the walls. This means putting a vapor barrier on the inside face of the wall insulation. You will want to make sure the un-faced batts completely fill the insulation cavity, so you will need material with a greater thickness than the R-19 six inch batts sold at your nearby big box store.

Now the challenge – you need to poke holes in the reflective wall insulation to allow any chance moisture from within the wall to escape. Trapping water vapor between the two vapor barriers will only lead to eventual grief in the form of mold, mildew and/or rot.

For the ceiling, it is essential to ventilate the dead air attic space you will be creating. Ideally your building was constructed with vented eaves and ridge and life will be good. You will want to use either un-faced batts, or ideally blow in insulation above your ceiling. Do not place a vapor barrier in the attic – as you want moisture to be able to rise into the attic space and be exhausted through the ridge vents.

Planning a new post frame building? If your building will have dimensions which could ever lend themselves to some or all of the building being used as conditioned space (heated and/or cooled), it would be prudent to design for it now, rather than having to face doing more work (as well as spending more money) at a future date.

This entry was posted in Insulation, Pole Barn Questions, Pole Barn Design, Building Interior and tagged pole barn living space, vapor barrier, post frame building, pole barn insulation on May 31, 2017 by admin.

An Apartment Addition?

DEAR POLE BARN GURU: Can you supply me with a copy of the sparrow barn in Texas plans It is a wedding venue I would like to copy. JAMES in HAMPTON

DEAR JAMES: Certainly we can, stamped by a registered professional engineer, and custom designed for your climactic loads – and for free. They come along with your investment in a new Hansen Pole Building complete kit package.

Pole Barn Prices

DEAR POLE BARN GURU: I built a 40x60x14 pole barn, trusses 4’oc, cement floor with seal, foil bubble wrap outside all girts and purlins, vented soffits and continuous ridgevent. Trusses have 5psf bottom cord rating. I have read all the posts of yours I could. Would like to put in 24×40 apartment and was looking to put in BIBS insulation with horizontal bookcase framing but ran into a few questions. I’m concerned about drywall cracking/nail popping if I strap bottom truss cords and apply drywall to that. If I drop the ceiling, however, I’ll have to do vertical studs for the ceiling joists to sit on. I see a problem with fireblocking too. How best do you fireblock behind posts (between girts) with bookcased studs? Vertical studs would be even more difficult to fireblock, with 1.5 inch gaps everywhere. Last question is insulation…..With the impermeable foil bubble wrap up against the steel siding, I was going to use the mesh fabric and BIBS only before drywall. I’m concerned about a vapor barrier against drywall as this will primarily be used in summer with a/c on the interior and an outside humid climate. I appreciate any help and advice. MARCUS in ROANOKE

DEAR MARCUS: I appreciate you being a loyal reader!

You will want to place 2×4 ceiling joists on edge (two inch face towards the floor and sky) every 24 inches between the truss bottom chords, using Simpson 2×4 joist hangers on each end. With 5/8″ gypsum wallboard, screwed on per the manufacturer’s installation instructions, it is unlikely you will experience unusual drywall cracking or nail popping. Properly done, your bookcase studs (wall girts) should be supporting the siding on the outside and drywall on the inside. Installed this way, they effectively serve as fire blocking. In the event your building has “barn” style wall girts (flat on the outside face of the columns), use bookshelf girts of a large enough dimension to reach the siding, as well as extend to at least the inside face of the columns (e.g. 2×8 on a 6×6 column).

There is going to be a challenge on the walls….your building should actually have building wrap on the outside of the framing to allow any water vapor in the wall cavity to escape to the outside world. The wall vapor barrier should be on the inside face of the wall girts to prevent moist air from inside of your apartment from entering the wall cavity. The reflective insulation in your walls should be either removed or at the very least punctured frequently, prior to wall insulation being installed.

DEAR POLE BARN GURU: I am installing shutters on my home, which is a barn style home with metal siding. My husband is very concerned about which type of screws to use to prevent leaking or rusting. What do you suggest? AMELIA in HONEA PATH

DEAR AMELIA: Builders Edge Shutter-Lok patented fastening system makes installation fast and easy. Shutter-Lok holds in any material. Shutter-Lok features a durable copolymer construction with molded-through color so that there is no paint to ever scratch, flake, or fade. Installation requires drill with 1/4″ masonry bit.

This entry was posted in Insulation, Pole Barn Design, Pole Building How To Guides, Pole Barn Planning, Ventilation, Rebuilding Structures, Building Interior, Professional Engineer and tagged fire blocking, humidity, shutters, fasteners, vapor barrier, Plans on December 26, 2016 by admin.

Spray Foam Insulation with Dupont Tyvek House Wrap

Hansen Pole Buildings Designer Rachel asked me about this today:

“I have more and more builders say they put Tyvek® on the walls and roof and then spray foam. This is so they can replace the siding/roofing in the future. Do you find any downfalls with this? I thought this was a pretty good idea.”

Having just written an article about spray foam insulation (https://www.hansenpolebuildings.com/2016/07/advantages-spray-foam-over-batt-insulation/), this is a well timed question.

Tyvek and all house wraps are NOT (I repeat NOT) vapor barriers. They are weather barriers: https://www.hansenpolebuildings.com/2016/01/determining-the-most-effective-building-weather-resistant-barrier-part-1/.

Spray-Foam-Insulation-150x150 In doing my research on the whys and why-nots I found apparently there are some spray foam insulation contractors who will not spray foam against house wraps, apparently from not being able to guarantee their product would properly adhere to the house wrap.

In one particular case – the spray foam insulation contractor tried to persuade the client to use BIBS® insulation (read about BIBS® here: https://www.hansenpolebuildings.com/2011/11/bibs/) due to the potential adhesion issues.

There apparently is an adhesive additive for spray foam, which will assist in the foam being able to stick to house wraps or other slick surfaces.

As closed cell spray foam is a vapor barrier, and is resistant to moisture passing through it in either direction, adding a weather barrier to the outside becomes redundant.

As a good, high quality steel roofing and siding should last the life of the building – installing any product between it and the siding, under the premise of making future replacement easier, it sounds much more like someone trying to make a feature into a benefit, than it does something which will add value to the client as a benefit!

This entry was posted in Insulation, Building Styles and Designs and tagged moisture barrier, vapor barrier, BIBS insulation, visqueen on July 13, 2016 by admin.

Concrete & Rain in My New Pole Building

This is a story which is heard all too frequently. And it always revolves around clients having just poured the concrete slabs in their new buildings. Even more so when the building has a low perm rated vapor retarder under the concrete.

Vapor retarders do exactly as their name implies, they retard the movement of water vapor through a system. They are not barriers which completely block the movement of moisture vapor. The amount of water vapor which passes through a vapor retarder is a function of perm rating, vapor pressure differential and penetrations.

The lower the perm rating of a vapor retarded, the better. A 1.0 perm rating will allow approximately 10 times more water vapor to pass through than a product rated 0.09, under the same conditions.

Moisture will flow from areas of high humidity or temperature to areas where these conditions are low. The force which drives the moisture through a vapor retarder is the vapor pressure differential.

wet concrete floor Freshly poured concrete contains a tremendous amount of moisture. In a typical two car garage (24 feet square) with a nominal four inch thick slab – the concrete contains approximately 138 gallons of water! As the concrete cures, much of this water is liberated into the air, increasing the relative humidity and vapor pressure within the building.

Ventilation is the simplest way to reduce humidity and vapor pressure and also lower the probability of condensation related problems. Failure to adequately ventilate a building during and after a concrete pour can result in condensation on the surface of the vapor retarder and potentially within any insulation. This is particularly critical in colder temperatures.

The easiest solution to “rain” after a new pour? Open up all of the doors and windows until the “rain” quits! And don’t panic – this will resolve the problem. My lovely bride came up with the idea of putting several fans on the concrete –but the concrete should NOT be forced to dry any “faster” as this lessens the overall strength of the finished concrete. You are best to retard the rate at which the concrete dries.

The whole point is – as the concrete dries, at its own natural rate, to ventilate out the moisture it releases into the air

This entry was posted in Insulation, Concrete and tagged pole building ventilation, pole building, vapor barrier, raining in a building, wet concrete on August 20, 2014 by admin.

Condenstop

Eric’s storage building has 5040 square feet of enclosed area. This made for a big roof. A big insulated roof which had a reflective radiant barrier applied between the roof purlins and the steel roofing.

Whatever type of insulation is chosen for this type of installation, if it is windy – it isn’t going to be fun.

So why even worry about roof insulation or vapor barriers?

Single skin metal roofs (typically found in pole building construction) are prone to condensation due to changing outdoor or indoor conditions. Condensation, sweating and dripping can have severe adverse effects on the condition of the building and its valuable contents.

CondenStop fleece is factory applied to the underside or inside of steel roofing and siding panels. It effectively reduces or eliminates the problems caused by condensation.

The Condenstop fleece absorbs, stores and releases significant quantities of moisture when condensation would normally occur. When the temperature of a steel roof drops below the dew point, the CondenStop fleece will absorb and store the condensing water vapor. The absorbed water will evaporate again into the ambient air under appropriate temperature and ventilation conditions.

Condenstop has been commercially available for 15 years and is the industry leader. It is made from durable polyester materials designed to last the lifetime of the steel panels. A wide variety of testing and in-place projects confirm the product’s durability. Once factory applied, the adhesion is quite strong and comes with a 20-year delamination warranty.

The product’s R-value is minimal, only 0.3691, however the product’s value is from its ability to store and release moisture where other materials cannot.

Moisture held in the CondenStop will not harm the steel. Full length panels should be used from eave to ridge to eliminate panel end laps and panel areas which are not enclosed. The bottom edge of the steel overhanging a fascia board, or areas in unenclosed overhangs – should be painted, or the Condenstop burned off to prevent microfibers from absorbing moisture from the outside.

The use of Condenstop does not take away the need for proper ventilation practices, either in performance, or under the Building Code.

CondenStop is Class I flame retardant per ASTM E84-04. It will hold 21 pounds of moisture per 100 square feet (equal to over 10 quarts of water). The microfibers do not support mold growth. It also reduces noise from outside such as rain as well as absorbing sound from inside the building.

On Eric’s building, we easily lost an entire day for the crew due to having to fight the winds installing a reflective radiant barrier. In wind prone areas – CondenStop is an option I would recommend, for the savings in labor costs and time alone. Next time – CondenStop for our building!

This entry was posted in Steel Roofing & Siding, Insulation and tagged building insulation, insulated steel, insulation, vapor barrier on July 8, 2014 by admin.

Dear Pole Barn Guru: How Much is Truss Weight??

New! The Pole Barn Guru’s mailbox is overflowing with questions. Due to high demand, he is answering questions on Saturdays as well as Mondays.

Welcome to Ask the Pole Barn Guru – where you can ask questions about building topics, with answers posted on Mondays. With many questions to answer, please be patient to watch for yours to come up on a future Monday or Saturday segment. If you want a quick answer, please be sure to answer with a “reply-able” email address.

Email all questions to: PoleBarnGuru@HansenPoleBuildings.com

DEAR POLE BARN GURU: Hello, I’m an engineering student doing a research about sustainable buildings, can you tell me the approximate 20′ metal truss weight and 24′ wood truss weight?

Please I need the answer urgently. CALCULATING IN KALAMAZOO

DEAR CALCULATING: Nice to have engineering students reading this column!

Having been given no parameters for load carrying capacity, truss spacing or roof slope, leaves me just winging out an answer.

For wood trusses with a total load of around 180 pounds per lineal foot (30 pounds per square foot spaced one at six foot or two at 12 feet), a single 24 foot span 4/12 slope truss weight should be about 125 pounds.

I’ve never dealt with steel trusses, however I was able to find several formulas, as well as a table for calculating the steel truss weight, W being weight per horizontal square foot, S = span in feet, P = capacity of truss in pounds per horizontal square foot, and A the distance center to center of trusses in feet:

Charles Evan Fowler, P. E., for Fink trusses:

W = .06S + .6 for heavy loads; W= .04S + .4 for light loads.

H. G. Tyrrell, P. E.:

W = .05S+ distance center to center.

C. W. Bryan, P. E.:

W = .04S + 4.

M. S. Ketchum. P. E.:

+ For scissors trusses increase one-third.

Weight Per Square Foot Of Roof Surface For Steel Trusses

		6/12 Slope	4/12 Slope	3/12 Slope
Up to	40 ft.	5.25	6.3	6.8	7.6
“	50 ft.	5.75	6.6	7.2	8.0
“	60 ft.	6.75	8.0	8.6	9.6
“	70 ft.	7.25	8.5	9.2	10.2
“	80 ft.	7.75	9.0	9.7	10.8
“	100 ft.	8.5	10.0	10.8	12.0
“	120 ft.	9.5	11.0	12.0	13.2
“	140 ft.	10.0	11.6	12.6	14.0

As you can see – lots of opinions on the steel truss (as are probably huge variants in their configuration).

DEAR POLE BARN GURU:We’ve just had a 40’x60′ steel pole barn constructed (in the woods) for storing classic cars. We had the builder install and frame fiberglass insulation in. We’re installing OSB wall panels ourselves. Wondering if we should cover the fiberglass with ‘Visqueen’ for vapor barrier or would we be better served by installing foil faced OSB panels?

Thanks CONCERNED IN KOKOMO

DEAR CONCERNED: Most often fiberglass batt insulation which is used in walls has a paper (or “kraft”) facing on the inside, which when properly installed serves as the vapor barrier. If unfaced batts were used, then a clear plastic vapor barrier should be installed on the inside face. Foil faced OSB panels are designed to be placed below roofing to assist in keeping attics cooler in warm climates, it is not designed to be or replace vapor barriers in walls.

This entry was posted in Pole Barn Questions and tagged vapor barrier, fiberglass batt insulation, pole building insulation, steel truss weigh, truss weight, wood truss weight, reflective radiant barrier on May 12, 2014 by admin.

Dear Guru: Can I Add to My Pole Barn in the Future?

DEAR POLE BARN GURU: I’m very interested in doing business with you, I just have a few questions. I originally asked for a quote of a pole barn of 200×50 I believe it was, my question is, can your buildings be added on to? Would we be able to start with something much smaller and then add on to the barn as we go? NOW IN NEW JERSEY

DEAR NOW: Yes, our buildings can be added on to. I would recommend the initial design be done with the idea of what the ultimate finished goal will be for size. Oftentimes, original structures are not structurally set up for the eventual expansion, which keeps the initial price low, but results in headaches and costs later, which could have been avoided with proper planning. A gabled roof will be the easiest roof style to work with when it comes to future expansion.

We have several customers who have done just as you suggest, adding on to one or both ends as they expand. Get the width you ultimately want, then adding length is much easier You can remove endwall siding, add on additional bays, and put the endwall siding back on. You may have to purchase more trims, but if steel siding, is easily reused for the addition.

And I always recommend – build as much building as you have space for and can afford economically, as whatever size you pick, it will never be large enough.

DEAR POLE BARN GURU: I’ve read ALL of your blogs! Back to 2010. And love them. I write similar stuff in my business.

The question is do you have, or can you get, closures similar to ridge vent, but as a bottom closure to be used at the eave of a building without overhangs? BREEZY

DEAR BREEZY: Thank you for your dedicated readership and …good question! There is not such a beast, and even if there was, the net ventilation would be tiny – not enough to yield any positive results, as the only area which could have a vent would be just at the high ribs. The correct way to vent would really be with enclosed vented overhangs.

DEAR POLE BARN GURU:I have an existing pole building with badly deteriorating insulation and vapor barrier for the roof.

I plan to pull all of the old insulation and vapor barrier out to replace it. I’d like to use the reflective radiant barrier / vapor barrier you recommend for new construction. I’m considering pulling the metal roofing off to do it right so I don’t have to do it again later.

Do you recommend installing the reflective radiant barrier / vapor barrier between the metal roofing and purlins or between the purlins and roof trusses? DETERIORATING IN DELAWARE

DEAR DETERIORATING:
Place the reflective radiant barrier over the purlins and directly under the roof steel. You will need to use larger diameter, longer screws to reattach the roof steel.

DEAR POLE BARN GURU:Where can I buy Owens Corning Foamular Fanfold foam 1/4″ thick? A lot of my fellow RC plane hobbyists are having a hard time finding this stuff. Thanks in advance. FLYING IN FREMONT DEAR FLYING: Visit the Contractor Desk of any The Home Depot®. If it is not in stock, it can be ordered in within a matter of just a few days.

This entry was posted in Pole Barn Questions and tagged vapor barrier, Ventilation, building add-ons, building additions, Owens Corning Foamular Fanfold Foam, pole barn remodeling, ridge vent, reflective radiant barrier on April 28, 2014 by admin.

Dear Guru: What Steps Should I Take to Add Insulation To My Pole Barn?

Welcome to Ask the Pole Barn Guru – where you can ask questions about building topics, with answers posted on Mondays. With many questions to answer, please be patient to watch for yours to come up on a future Monday segment. If you want a quick answer, please be sure to answer with a “reply-able” email address.

Email all questions to: PoleBarnGuru@HansenPoleBuildings.com

DEAR POLE BARN GURU: My question concerns insulation and ventilation. I have an existing 30 x 50 pole barn. It is split in half lengthwise, with one half enclosed and the other half open on one side. I am wanting to frame and enclose the open wall and make the building into a woodworking shop. I would primarily use this shop during the warmer months, but would like to be able to work in there in the wintertime on occasion. I am planning to re-tin the entire building including the roof. The current enclosed portion has trusses that span roughly 15 feet from wall to wall with a 12/3 pitch. The area that I am wanting to enclose is “lean to” construction with 2 x 10 rafters that span from the truss beams of the already enclosed area to a double 2 x 12 beam (approximately 15 feet). My building does not have soffit ventilation or ridge ventilation. From what I have learned from your blog, I am planning to add reflective barrier between the purlins and metal roof when it is replaced. I also know that my trusses are most likely not designed to bear the weight of a ceiling and insulation. I would like to either insulate the entire building or at least the newly enclosed area and keep the other as cold storage. I would like to know what options I have to make either of these a reality and what steps to take as far as insulation and vapor barrier is concerned? I have included my e-mail and I tried to include photos but could not attach them. Please respond with your e-mail and I will send the photos right away and any additional information you might need. Thanks so much! NO CRISIS IN KANSAS

DEAR KANSAS: We did figure out how to get photos from your hands to our eyes, thank you very much for your efforts.

After seeing the photos, my response was, “Rather than throwing a lot of dollars into your existing building, have you considered just leaving it as is for cold storage, and putting up a new woodworking shop?”

I’ve written in the past about renovation and remodel work on pole buildings:

https://www.hansenpolebuildings.com/blog/2013/01/pole-barn-remodel/

https://www.hansenpolebuildings.com/blog/2013/05/renovating-a-pole-barn/

A little more input from this very kind gentlemen helped: “I was trying to use my existing building because it already has concrete floors and 200 amp electrical service.”

And back from me: “Trying to re-purpose and existing building is rarely the most economical or practical solution. Especially if it involves the cost of residing and reroofing (since these two items typically represent about 50% of the cost of the building). In looking at the photos, the way the concrete is poured leads me to believe you are going to have water coming in under the outside building wall.”

What clinched me having to help this guy out was: “The existing barn may be my only option due to the wife wanting its appearance improved regardless!”

If mama ain’t happy, ain’t no body happy!

As I do not know the version of the Building Code (if any) your building was constructed under, nor the applicable wind and snow loads, I can only make broad structural recommendations. In most permit issuing jurisdictions, they work you propose to do does require a building permit to be acquired. I’d recommend you confirm yes or no.

In the end, it would be an excellent idea to contract with a registered design professional RDP (engineer or architect) to confirm structural integrity of the existing building, as well as to appropriately size new members being added, as well as their connections.

Starting with the basics, remove all of the siding and roofing. Where an exterior wall will have a climate controlled area opposite, remove all girts. Install new wall girts at 24 inches on center, of a size large enough to be flush on the outside of the walls with existing pressure treated splash planks, etc. With 6×6 columns, it will take 2×8 girts placed like bookshelves. In order to keep wall screw lines even, you may want to opt to swap out the girts universally (it also allows the future ability to insulate other portions of the building at a later date).

As you will be down to bare framing, I would highly recommend adding enclosed vented overhangs on all four sides of the building. This will allow for an air intake, which is going to be essential to the overall system performance during steps outlined below.

Before installing new roof steel, install the reflective radiant barrier on top of the roof purlins. I recommend the A1V product from www.buyreflectiveinsulation.com, as it has tabs with adhesive pull strips to seal each piece to the prior one. Use high quality vented ridge closures under the ridge cap, to provide an air exhaust.

Wrap the building walls with a high quality building wrap.

In areas you want to climate control, install a 2x beam (or header) to the inside face of the columns. From beam to beam ceiling joists can be placed every two feet to support gypsum wallboard.

With the newly created wall cavities, you can use batt insulation or BIBs. For the ceiling, I’d suggest blowing in insulation, once the ceiling has been drywalled.

Assuming you move forward with this, I am hoping you won’t mind sharing progress photos.

When it is all done, it should look and function just like a new building.

This entry was posted in Insulation, Pole Barn Questions and tagged insulation and ventilation, reflective radiant barrier, vapor barrier, pole barn insulation on April 14, 2014 by admin.

Dear Guru: Do I Need Vapor Barrier Under Insulation?

Welcome to Ask the Pole Barn Guru – where you can ask questions about building topics, with answers posted on Mondays. With many questions to answer, please be patient to watch for yours to come up on a future Monday segment. If you want a quick answer, please be sure to answer with a “reply-able” email address.

Email all questions to: PoleBarnGuru@HansenPoleBuildings.com

DEAR POLE BARN GURU: Is it a huge mistake to go without a vapor barrier on the walls? How about Tyvek on the walls during construction? I was thinking of doing Tyvek between the metal siding and the purlins to at least get that vapor barrier in there, just in case I decide to put insulation in my walls later when the budget allows. Thoughts? CONTEMPLATING IN KANSAS CITY

DEAR CONTEMPLATING: If you EVER think you or the person(s) who own your pole building after you, will ever apply insulation to the walls of a building – then placing a quality house wrap between the wall girts and the siding (whether it be steel or any other material) is an excellent idea for a vapor barrier. At time of construction is the one single time in which it will be extremely easy to add.

To learn more about house wrap: https://www.hansenpolebuildings.com/blog/2012/11/house-wrap/

DEAR POLE BARN GURU Insulation – I read your warning about the steel skin acting like “unibody” construction, so it should be applied directly to framing. What is a good way to use foil-faced foam board for putting insulation on a roof? I want to avoid using the large rolls of insulation that will sag in 6-8 years? LEARY IN LOUISIANA

DEAR LEARY: I am glad you have been reading and paying attention. Your new building will be well planned, with pleasing results. I just am seeing no way for foil-faced foam board to be a practical and economical solution for roof insulation. Here is a link to an article I wrote which might give you some further food for thought:

https://www.hansenpolebuildings.com/blog/2013/07/insulation-6/

This entry was posted in Pole Barn Questions, Insulation and tagged vapor barrier, housewrap, foam board insulation, foil-faced foam board, tyvek on October 28, 2013 by admin.

Moisture Barrier: A Bad Place for Plastic

Eric, one of the owners of Hansen Buildings, was chattering with me today about the number of interesting telephone calls he fields. Many of these are probably due to this blog, as well as “Ask the Pole Barn Guru” – the weekly advice column for those with pole building questions, concerns, or who just are looking for free therapy.

A gentleman had recently erected a pole building, and placed six ml (0.15 millimeter thick) clear plastic visqueen as a vapor barrier between his sidewall girts and wall steel.

Visqueen is a brand of polyethylene plastic sheeting produced by British Polythene Industries Limited, and has become a generic description for any plastic sheeting (think Kleenex). Because I know lots of near worthless trivial information, it is important to know Visqueen was first produced about 1950 by the Visking Corporation, a company founded in the 1920s by Erwin O. Freund for the purpose of making casings for meat products. Visking investigated the post-World War II emerging technology of polyethylene, and developed manufacturing techniques to make pure virgin polyethylene film. Originally spelled VisQueen, the film is an excellent moisture barrier and was marketed to many industrial, architectural, and consumer applications, such as moisture barriers, plant seedbed protection films, building fumigation barriers, drop cloths, case liners, and tarpaulins.

Anyhow, in the application above, there isn’t any problem….until the building owner wants to insulate the building walls, then place another vapor barrier on the inside of the walls.

Every Fall, when I was a youngster, my grandmother would make massive quantities of apple sauce, at their lake cabin. All of the wonderful smelling boiling concoction put lots of water vapor into the air of the kitchen. When this warm moist air met the nice cool window glass, it became condensation. The same happens with any surface or material which stops vapor. For example, the painted surface of the drywall will also prevent most moisture from passing through …. which is why higher gloss paint is used in kitchens and bathrooms. If the drywall were not painted, the moisture / vapor would simply absorb into the drywall material. So think of the paint as a type of moisture barrier to protect the drywall.

But vapor can occur even without obvious introduction of moisture into the air. Wherever warm air meets cold air there will be a high concentration of vapor in the area. So wherever the vapor barrier is placed in a wall is where the condensation will occur.
Think of it as a cold and warm weather front meeting inside a wall …. and the forecast is rain.

The condensation held by the vapor barrier will eventually go back into the air once the volume of vapor decreases. This is allowed to happen only if there is good ventilation on both sides of the barrier.

Vapor will penetrate any material in its way until it hits a barrier, this is why it is important to position vapor barriers on the warm (inside) side of walls. When warmer air meets colder air condensation will develop. Imagine the damage to insulation if the barrier was on the outer side of the insulation? Warm air (and/or moisture) would create condensation on the vapor barrier which would eventually absorb into the insulation causing all kinds of water damage and possible mold growth.

Our friend would have been so much further ahead by having used a house wrap between the wall girts and the steel siding, as house wrap is permeable (it allows excess moisture to pass through).

My expert advice would be to slice holes in the visqueen to allow any accumulated moisture to pass through.

This entry was posted in Insulation, Steel Roofing & Siding, Pole Building Siding, Building Interior and tagged vapor barrier, moisturer barrier, visqueen, wall condensation on July 16, 2013 by admin.

What House Wrap is Good For

Over the past three decades, house wrap has become a staple feature on millions of buildings. Wrapping a wood framed building in a protective envelope is a good building practice which helps combat a building’s worst enemies: water, moisture and air infiltration. House wrap behind a building’s siding is an excellent secondary defense against the weather.

House wrap is a weatherization membrane which provides a protective layer under a building’s siding and over the wall girts or sheathing. It is literally wrapped around a building, cut out around windows and doors and taped at the seams.

The unique, nonwoven-fiber structure of house wrap resists air infiltration and water intrusion, yet is engineered to readily allow moisture vapor to diffuse through the sheet, helping prevent mold and mildew buildup and wood rot. The fibrous structure is engineered with microscopic pores which readily allow moisture vapor to evaporate but are so small bulk water and air cannot penetrate. Siding, whether vinyl, wood, stucco, brick, or composite, does not completely prevent air and water penetration. House wrap is designed as a secondary defense to help manage a building’s wall systems.

R-Value ratings for insulation are only maintained as long as the air within the insulation stays still and dry. The Department of Energy estimates nearly 40% of a building’s energy loss is the result of air infiltration caused by wind driven pressures from the outside. The opposing forces of pressure between inside and outside walls cause heat and air conditioning to be virtually sucked from a building– through walls, ceilings, sill plates, sheathing joints, top plates, electrical outlets and every inch of the estimated half-mile of cracks in newly constructed buildings. As air infiltrates, it causes changes in temperature which require heaters or air conditioners to work harder. Constant temperature fluctuations also reduce comfort levels. Occupants feel too cold or too warm. Reducing air infiltration increases a building’s comfort factor.

Insulation can help increase the R-value, but it is only marginally effective in reducing air infiltration. When air infiltrates, the R-value itself can be reduced up to 60%. Adding thicker insulation won’t solve the problem. Stopping air from getting in, will.

Properly applied, house wrap helps reduce air infiltration, preserving R-values, conserving energy, reducing heating costs and creating a more comfortable interior.

The tighter the building, the more comfortable and efficient. Unfortunately, the tighter a home, the more susceptible to moisture problems which can cause mold, mildew and rot. So all systems need to be in balance–designed to manage water and moisture effectively.

There are two main ways water and moisture get into wall systems:

Bulk water intrusion from the exterior (rain and snow) can enter the wall and, if not allowed to dry in a reasonable amount of time, can raise the moisture content of the wood above 30% and cause rotting or mold and mildew.

Air transported moisture occurs when air leaks from the warm side of the wall to the cool side. Warm air will hold higher amounts of moisture than cold air. As warm air travels through a wall heading to the cold side, it will begin to cool and be forced to release moisture. This is called the dew point where condensation will occur. When there is a significant temperature drop across the wall, the dew point will occur somewhere within the wall. In the winter months the point of condensation is usually on the inside surface of the exterior sheathing. Moisture carried by air flow through the wall is deposited at the back side of the sheathing and accumulates. In hot and humid climates where air flow is traveling from the outside to the inside, warm moist air from the outside will be cooled on the way to the air conditioned inside, releasing moisture within the wall cavity. House wrap is a breathable membrane with microscopic pores which allow the moisture vapor to dissipate, helping to dry out a wall system to avoid damage.

Moisture Vapor Transmission Rate or perm rate of a material determines the ability for water vapor to diffuse or evaporate through the wall. The higher the perm rate, the more “breathable” the material is and the easier it is for water vapor to pass through. Materials with Perms below 1 are considered vapor retarders since the rate of moisture vapor flow through a 1 Perm material is so low there is essentially no flow. House wraps have Perm rates in the area of at least 58 Perms which is very open to allow moisture vapor to flow through.

What house wrap is not, is a vapor barrier or an insulation. I’ve seen instances where people have applied house wrap directly between roof purlins and roof steel, in an effort to control condensation. House wrap is quite permeable; any warm moist air which would rise to it will pass through to the underside of the roof steel and condense.

House wrap is great…if used for what it was intended for…a secondary defense against the weather.

This entry was posted in Ventilation, Roofing Materials, Pole Barn Planning and tagged vapor barrier, pole building insulation, condensation control, perm rate on November 12, 2012 by admin.

And Now…Insulation Crime!

If you didn’t read yesterday’s blog – is good to catch up as a lead-in for today – well worth the time. In it I discussed a problem a reader had asked for tech support about an insulation issue.

So today – yet another reader has written….

“I am in the process of finishing a pole building. The building will be used as my workshop and it will be heated, I live in Washington State. The contractor that put up the exterior placed R-23 Kraft Faced fiberglass insulation between the 2 X 6 rafters with the facing against the metal corrugated roof. This means that the vapor barrier is facing the roof, not the inside of my building. I plan to install sheetrock on the ceiling. It is not uncommon for the temperature to dip below zero here, and in the summer reach 100 for a month or more. My question is can I place a 4 mil poly vapor barrier on the interior side of the roof thereby wrapping the fiberglass insulation in two vapor barriers?”

What this building owner has is a pole building with 2×6 roof purlins on edge. Condensation on the inside of steel roofing applied directly on top of purlins can be an issue. This particular builder errantly installed batt insulation with the vapor barrier towards the steel, in efforts to reduce or eliminate the condensation problem.

If the builder would have properly installed the insulation between the purlins, with the Kraft facing towards the climate controlled area, making sure all seams were sealed, it would have been both effective as insulation and the vapor barrier would have kept the warm moist air inside the building, from condensing on the underside of the roof steel.

Why do I call this scenario “insulation crime”? Because the builder took his client’s hard earned money and in return, gave him nothing but a problem to be solved.

Nearly every jurisdiction in the state of Washington requires both a Building Permit as well as the inspection of new buildings under construction. If this was a permitted building, the Building Inspector should have noticed the improper insulation installation and issued a correction notice – rather than signing off on a final inspection.

This entry was posted in Pole Barn Planning, Steel Roofing & Siding and tagged vapor barrier, vinyl vapor barrier, batt insulation, pole building insulation, insulation under steel roofing, Kraft faced insulation on October 4, 2012 by admin.

Insulation Dilemma

A reader writes (spelling, grammar errors included):

“When I built my barn I had 2″ insulation bats put between the outside framing and the tin. The side toward the tin is just open insulation. The inside is that heavy with plastic or whatever it is. I built with books shelve perlins on 2′ centers. Thinking it would make it an easy job to just fill those cavities with insulation.

Where I’m confused is on the vapor barrier. We have a local business that makes insulation. Actually my insulation came from them. They guy there told me to just slice open the white vapor barrier and add insulation then use plastic over the added insulation prior to finishing my walls. So I’m just looking for affirmation that this is the correct way to go. Or other ideas and opinions.

Thanks.”

From the description, I will assume the two inch insulation batts are what is known as Metal Building Insulation. This type of insulation is actually designed to reduce condensation issues in building which have steel roofing and/or siding applied directly over roof purlins or wall girts.

Metal Building Insulation is not an effective insulator, as the fiberglass insulation gets crushed down to nothing every time it crosses a framing member.

This particular building is designed with sidewall framing (girts actually, not purlins which are on a roof) placed bookshelf style to create an insulation cavity. The builder did not do his customer any favors and actually spent his customer’s money unwisely.

Moisture within the walls of a pole building can cause serious problems. In the colder months, moisture tends to move from the inside to the outside of buildings. As it passes through the walls, it may condense within them, causing the potential for rot and mildew. In walls with insulation, the water may condense within the insulation decreasing its R-value. In the worst case, moisture can actually freeze within the walls, accumulating until a thaw melts it and causes visible damage such as wall or ceiling staining!

A vapor barrier is designed to keep moisture in pole barns from getting inside exterior walls. Batt and roll insulations usually come with a vapor barrier attached. However, leakage can occur where the facings meet. This is especially true if the facings are not stapled to the inside of the wall girts, but instead the insulation is just pressed into place or stapled on the inside of the girt (all too common of a practice with foil faced insulation). For the best possible vapor barrier, supplement the facing by installing a 4mil or thicker clear plastic sheet over the inside of the entire framed wall before installing any interior finishes (like gypsum wallboard).

Never sandwich the insulation between two vapor barriers. For example, do not install insulation with the vapor barrier facing the climate controlled space and then put plastic sheeting, or some type of vapor barrier, across the outside of the framing. Since some leakage of moisture into the insulation in inevitable, it needs to be able to freely escape from the insulation to the outside world ….. not be trapped inside!

This entry was posted in Pole Barn Planning, Pole Barn Structure, Steel Roofing & Siding and tagged roof insulation, vapor barrier, metal building insulation, wall insulation on October 3, 2012 by admin.

Building Insulation: Vapor Barrier

Insulation is one of the topics, once brought into conversation, seems to make most folks’ eyes glaze over. Many know enough to ask about R Value, and understand “the higher the better”. Or so they think. Sometimes you need to stop a minute and go back to the source of what I call “the need”. This is the way I teach our Building Designers, and clients as well, to think about any feature or addition to their pole building kit when they design their new building. What are you going to need for your building? Don’t just throw a bunch of stuff in and on there because it “my neighbor put it on his building”. What are your needs? Obviously we all choose features we want on our building, “just because”. Just because it looks nice, gives the building a classier look, a lower profile, or we think the eagle on the weathervane hovering over the cupola is “pretty cool”. This is all well and good, but insulation is not one of those “pretty parts” of a building. Necessary yes, but what type and where do you put it?

When I designed my most recent pole building for my own use, I researched several types of insulation, and ended up using not one or two, but three different types of insulation, and each of them for their own specific purpose in relation to cost. In other words, “what is the cost value” for each of them?

The types of insulation I looked at ranged from what most folks think of when you say “insulation”: fiberglass insulation, to foam board, spray on foam and B.I.B.’s (Blow in Blanket) along with the reflective type vapor barrier insulation in various configurations and applications. I ended up putting reflective radiant barrier under my roof steel, wrapped my entire outside of the building in a reflective radiant barrier, put reflective radiant barrier under the heated concrete floor, fiberglass insulation in the interior walls, and then B.I.B.’s in the exterior walls. Wow, I hear clients saying, “How do you know what to put where?” Easy – once again it goes back to the “need”. Over the next couple of days I will cover a few of the insulation choices out there, so get out a sheet of paper, make yourself a grid, and next time you need insulation, ask yourself these easy questions to decide “which insulation you are going to put where” in your new pole building.

First question, what is R value? For those of you who are not familiar with R values, it is simply the measure of resistance to heat flow. R-1 is equal to the resistance of a 1” thickness of wood. Insulation materials have tiny pockets of trapped air. These pockets resist the transfer of heat through material. The ability of insulation to slow the transfer of heat is measured in R-values. The higher the R-value, the better insulation’s ability to resist the flow of heat through it. Before you consider these products, read the test reports carefully. In order to achieve the full promised values, the products must be installed in the center of an appropriate dead air space.

Second question, what are you going to be using your building for? This will help you to determine what type of insulation you are going to need. Of course, your “need” for insulation also depends on where you live. If you are in Minnesota where I have my newest building, and want to change the oil in your car in January, putting reflective radiant barrier in the roof and even on the walls is probably not going to keep me warm. No heating system is going to keep up with the heat pumping out of my building!

And, if you live in Knoxville, Tennessee and are OK working in your shop with coveralls on a few hours a week, your insulation answer will be greatly different than if you want to sit in your new shop in your shirtsleeves with your buddies watching the Super Bowl come January!

So your first project is this: take a sheet of paper and write down all the things you want to “do” within the confines your new building, including keeping pets, horses, or other animals at the right temperature. Also make a list of other reasons we put insulation in spaces – noise for one. Do you need good sound abatement for the “practice garage” for your son’s rock and roll band? Is the loft bedroom right above where you work on motors or have a workshop with noisy machinery?

Once you decide on what your needs are for insulation, you can just match it to the Insulation Grid we’ll be making over the next several days. I’ll be back tomorrow to start with the simplest of all insulation: reflective radiant barrier which includes a vapor barrier. Winter is coming, so stay warm!

This entry was posted in Pole Barn Planning and tagged insulation, vapor barrier, fiberglass insulation, reflective radiant barrier on November 15, 2011 by admin.

Lying or Just Plain Stupid?

Yesterday afternoon, one of our senior building designers sent me this instant message:

“So what do you do with a customer who is being sold a bill of goods by his contractor? Starting from, client was told he needed to pour footings and build with 2×6 studs because pole buildings ‘move too much’. All the way to – ‘you need to sheet your walls and roof with plywood before you put steel on’. This is because of security and dust coming through the walls. Not to mention on the roof for a vapor barrier.”

It amazes me the ignorance about pole buildings after over 80 years of solid pole building construction.

A bit more about this particular client’s building. It is 40’ x 80’ with a 14’ eave height. The client initially contacted the builder to get a labor quote only – to construct a Hansen Building kit. The client specifically asked for one of our pole buildings. The builder told this client a pole building would be way too complicated to construct and the stick frame building would be less expensive.

Let’s look at the realities of the situation. To construct a stick frame building will take excavating a trench around the perimeter of the building to below the frost line (and it DOES freeze deep in Maine). A footing must be formed and poured. With a wall this tall, I’d imagine at the least it would have to be eight inches thick and 16 inches wide with rebar in it. On top of the footing will need to be formed up a foundation wall. This foundation is going to be a minimum of four feet tall, due to the frost depth. The wall should probably be an eight inch wall, but assuming six inch thick, three truckloads of concrete will be used for the footings and foundation! With the pole building, holes are augered in the ground and around five yards of concrete are required for the backfill. Pretty low tech and saves a bunch of money in equipment, materials and labor.

A kicker the contractor may not have considered, or has ignored….the maximum stud wall height allowed (according to code) without engineering is 10’. His building is going to need to be designed by a registered professional engineer in order to meet code requirements.

As far as “movement”, steel roofing and siding has shear values nearly equal to those of 7/16” osb or ½” plywood. Imagine the steel as being very thin, very strong plywood. It is the sheathing of a building which holds the frame stable, not the framework. With steel and plywood virtually equal for strength, it takes away the “movement” issue. Our Hansen pole building office is 44 feet high from ground to roof peak and has no noticeable movement in even the extreme wind loads of South Dakota.

Moving on, let’s address the issue of “eliminating dust”. Each steel panel overlaps the adjacent panel which prevents dust infiltration. Base trim (aka “rat guard”) keeps dust from entering around the base of the building. All other steel edges have trims which cover possible infiltration areas. The eave edge of the roof steel and under the ridge cap are sealed by form fitting closure strips, which seal those areas.

The only place for dust to enter either style of building is going to be via an open door! Same goes for security – your building is only going to be as secure as the quality of the doors. Chances are the builder is going to provide entry doors with wood jambs, which is an invitation to enter via a good swift kick. The commercial steel doors we provide have steel jambs as well. No one is going to break those jambs with a kick.

As for a vapor barrier, our buildings come standard with a reflective radiant barrier for under the roof steel. With our exclusive PSA (pull strip attached) adhesive strips, proper installation assures the elimination of condensation. A side benefit being the increased insulation value and the reflective radiant barrier is superior against heat gain. Using plywood on a roof proves to be expensive, adds weight to the roof system and requires the use of asphalt felt paper or other similar and materials to create a water tight seal.

If ignorance is bliss, this particular contractor is either very happy, or he is feeding a line to the client. If the first, he is doing no justice to the client, if the second, he’s worse yet. My guess is… stick framed is all he knows. He is just too lazy to try something “new”, easier….and cheaper for the customer, while being just as solid, air tight and long lasting.