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Condensation on Inside of New Vinyl Windows

Condensation on Inside of New Vinyl Windows

Is it a bad sign if you notice condensation forms on your new vinyl windows inside? is condensation on windows bad?

It isn’t a bad sign if you notice water collecting on window’s inside. But, there are a few things you can do to minimize window condensation and protect quality of your new windows.

What causes condensation? When warm air comes in contact with cool surfaces then condensation can form. Consider a time when you carried an ice-cold beverage outside on a hot summer day. Hot air outside comes in contact with a glass’ cool surface, and then moisture forms on glass’ outside. This reaction is why so many people are adamant about using coasters to avoid damage to tables and furniture.

In this same way, windows can “sweat” on a cold winter day. Inside, you are toasty warm while heat is running. Freezing air outside comes in contact with window glass causing moisture to form on inside of windows. Common daily activities can increase moisture in your post frame building, “sweat” found on windows. A hot bath or shower will release moisture into air. Cooking can also affect humidity levels in your post frame home or barndominium.

Risks of indoor air condensation can sometimes be higher with energy efficient windows. These products seal your post frame building and prevent drafty air from moving through frames. Since your building is sealed, heat and moisture are trapped inside. These features, making your windows more energy efficient, also lock in moisture thus increasing risk of condensation forming.

Many northern climates can be cold and dry during winter months, so many building owners welcome extra moisture inside. Increasing humidity levels make your post frame home more comfortable and reduce need to use lotion every day. Too much humidity can lead to mold growth and other damage to your post frame building. So, it is important you are proactive to reduce indoor humidity if you start to notice problems.

Improve air circulation by running fans. Ceiling fans are great for large rooms or use bathroom or kitchen exhaust fans. If weather is nice outside, open windows to bring in fresh air.

This entry was posted in Ventilation, Windows, Building Drainage, Building Interior, Pole Barn Heating, Barndominium, Pole Barn Design and tagged vinyl window condensation, condensation, pole barn condensation, humidity, vinyl windows on September 17, 2024 by Rick Ochs.

Twelve Foot Addition, Wall Insulation, and Purlin Settings

This Wednesday The Pole Barn Guru answers reader questions about extending an existing 60′ long pole building by twelve feet, the best way to insulate outside walls to prevent sweating, and the reasoning behind setting purlins flush with the top of the truss top chords.

DEAR POLE BARN GURU: I have an existing 40 x 60 pole building, built in the late 80’s. It has double trusses spaced 12 ft apart. I would like to extend it from 60 to 72 ft. We originally were thinking we would extend using stick frame construction but now I am wondering if this will affect the integrity of the existing building. I would like to leave the end of the pole building in place and add a door into the new space at each end. Your advice on the best way to go about this? The extension is planned for a bathroom and laundry space and would have a concrete floor. Thanks for your help. WENDY in VANCOUVER

DEAR WENDY: Adding as a post frame (pole) building will be your most economical and easiest route to go, especially as your Building Department will require engineer sealed drawings and verifying calculations. In order to determine how best to achieve your end goals, we would need detailed photos of inside and outside of your existing building, measurements at eave sides and dead center from bottom of pressure preservative treated splash plank to underside of roof steel, spacing of existing endwall columns, etc. We make deliveries into Western Washington and Northwest Oregon frequently, so freight costs will be quite reasonable. Please forward your information to Caleb@HansenPoleBuildings.com along with site address and best contact phone number.

DEAR POLE BARN GURU: I built a pole barn last year and am having the floor poured this week. Once completed, I will begin building an apartment inside the barn area. What is the best way to insulate the outside walls for great R value and prevent sweating? DAVID in PORTSMOUTH

DEAR DAVID: If you placed a Weather Resistant Barrier (think Tyvek or similar) between your framing and siding, then fill your insulation cavity with Rockwool and have a well sealed vapor barrier before interior finish. If no WRB, then have two or more inches of closed cell spray foam applied to inside face of your siding, then fill balance of cavity with rockwool and no interior vapor barrier. Depending upon what you do with your under slab and roof for vapor barriers and insulation, you may need to mechanically dehumidify in order to prevent condensation (sweating), as your walls alone are merely a small piece of a big puzzle.

DEAR POLE BARN GURU: I understand your roof design is with purlins flush with the top of the truss. Why do you use this design? Sorry if this info is on your website, I didn’t see it. Regards, STANLEY in DOSWELL

DEAR STANLEY: Here is an article on this subject: https://www.hansenpolebuildings.com/2019/02/where-oh-where-should-my-purlins-go/

Having roof purlins flush with top of trusses has many advantages:

It does not take up extra height (purlins over top of trusses either reduces interior clear height or increases eave height).

Purlins are then in perfectly straight lines, allowing for pre-drilling of roof panels (this eliminates misses). Others may try to align purlins over top of trusses using butt end splices. This makes for a very poor connection attempting to get adequate fasteners into 3/4″ (1/2 width) of truss top chords. When purlin joints are lapped, it causes a stagger of the purlins, resulting in inability to pre-drill and a significant chances of screw misses.

Purlins can be connected to trusses using engineered and Code conforming parts (in our case, quick to install Simpson Strongtie PFDB26B). Codes (as well as sound engineering practice) require purlins on edge to be solid blocked or otherwise prevented from rotation at ends. A nailed only connection would not meet this requirement).

This entry was posted in Rebuilding Structures, Pole Barn Questions, Budget, Pole Barn Design, Columns, Constructing a Pole Building, Sheds, Pole Barn Planning, Pole Barn Structure, Barndominium, Footings and tagged addition, post frame addition, insulation, condensation, PFDS26B hangers, Ventilation, extension of building, wall sweating, purlins on September 11, 2024 by Rick Ochs.

My New Riding Arena Has Condensation and Birds

My New Riding Arena Has Condensation and Birds

Reader BETH in LEBANON writes:

“Last fall I had an indoor riding arena built 70 x 152 x 16 that had a built in vapor barrier. The building has cathedral trusses. This is a stand alone building with no stable attached. I have had condensation in the building, especially at certain times. The floor is crushed limestone. I have experienced a bird problem and am thinking of adding a ceiling and maybe indoor panels to keep the birds out and from roosting. I also had been debating about adding insulation. Here are my questions:1. What recommendations would you have re: condensation issues when I add ceiling and maybe the indoor metal panels? 2. If I did add insulation, what type(s) do you use in this situation to provide best outcome and address condensation? I am trying to understand potential temperature impacts in extreme seasons; if it is in the 90’s outside what can I expect the differential to be inside and same with winter. I realize in winter the footing will impact potential difference due to the size of the cold floor.3. Any other comments/recommendations for this type of facility?”

Your ‘built in vapor barrier’ is most likely not a vapor barrier, but rather an Integral Condensation Control (ICC). Read more about ICCs here: https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/

ICCs work well when provided with adequate eave air intakes and ridge exhausts. Without these, you are likely to continue to have condensation issues, even with a ceiling installed.

Your moisture is coming up through your crushed limestone and from your horses. Ideally a heavy vapor barrier (like 15 mil) would have been placed under your limestone to prevent moisture from coming up.

Before putting in a ceiling, you will want to reach out to whoever engineered your building, to make sure you can remove those largely ineffective and possibly negatively impacting knee braces (https://www.hansenpolebuildings.com/2023/10/knee-braces-in-post-frame-buildings/). You also need to verify those trusses will even support a ceiling, as large span pole barn trusses are rarely designed for this extra weight.

In directly answering your questions:

1) Properly vent your attic space, otherwise expect long term problems

2) You need to be able to keep attic air and outside air at same temperature, could take as much as R-60. My preference would be blown in granulated rockwool, as it is unaffected by moisture, however it is heavy compared to fiberglass. Your choice will likely depend upon weight capacity of trusses.

With a steel liner panel ceiling, you may experience condensation on underside of panels, especially if you under insulate. Without an ability to heat and cool, your interior space will be close in temperature to outside – other than summer temperatures will be more like being under a shade tree.

3) In lieu of an under floor vapor barrier, make sure grade outside of building slopes away at least 10 feet in every direction by at least 5%. If you do not have gutters, get them installed, with downspouts running off again no less than 10 feet from building.

This entry was posted in Ventilation, Building Interior, Budget, Insulation, Pole Barn Questions, Horse Riding Arena, Roofing Materials, Pole Barn Planning, Pole Barn Structure, Barndominium, Trusses and tagged Ventilation, attic condensation, riding arena, liner panels, condensation, floor vapor barrier on July 16, 2024 by Rick Ochs.

Avoiding Condensation When Insulating an Existing Pole Barn

Avoiding Condensation When Insulating Existing Pole Barn

The last thing people want to have to deal with would be condensation dripping in their pole barn. When an originally unheated cold storage building becomes repurposed to be climate controlled, possible condensation poses some new challenges.

If you are reading this article and plans are to construct an unheated building, I implore you to consider taking steps so it could be repurposed to be heated and/or cooled later. Please browse through some of my previous articles regarding this subject, such as: https://www.hansenpolebuildings.com/2018/06/pole-barn-insulation-oh-so-confusing/.

Reader JOSEPH in ALPINE writes:

“We have a pre-existing pole barn that we want to turn into a insulated building. Knowing that condensation would be a problem, I’m looking for a professional to consult with so it is done correctly. Is this something you do and what are your rates?

The building is 15×15, on a pad. There is no attic- 1/4” plywood is nailed to the ceiling 2x4s. We’d like to keep this height since it affords space for a loft. There is a single central roof vent. I read your response to one customer about using unbatted insulation on the walls and punching holes in the plastic to allow venting. But how does one allow for venting when there is no attic space? Our main house (1937 farm home, remodeled to modern code in 2003) is a metal roof with the upstairs rooms opened up, no attic, no roof vents. How can one replicate what is done in the house with this pole barn?

Thanks.”

Mike the Pole Barn Guru writes:

I am deeply flattered to have someone offer to hire me for a consultation. Here is my response to Joseph:

I am a bit geographically inconvenient to be able to come and see your building. However, based upon experience and what I would do if it was my own building, I will give you some free advice. You are welcome to use it, or discard it as best you see fit.

As you do not know if a vapor barrier exists beneath your existing concrete slab, I would use a high quality surface sealant over it. Your major water source for potential condensation will be through this slab. I’d close off roof vent, and have inside surface of siding and roofing closed cell spray foamed. Your local installers can give you recommendations for thickness, however I would not go with less than two inches thickness. If possible or practical, unfaced fiberglass insulation may be added to the inside to increase R value. However, it might be most practical to just pay a little extra for thicker spray foam.

This entry was posted in Insulation, Pole Barn Questions, Pole Barn Planning, Ventilation, Concrete and tagged closed cell spray foam, condensation, insulating a pole barn, unfaced batt insulation, insulated pole building on July 2, 2024 by admin.

Will I Have Issues With Post Frame Closed Cell Spray Foam Insulation?

Will I Have Issues With Post Frame Closed Cell Spray Foam Insulation?

Reader HEATH in NACOGDOCHES writes:

“I am building a pole barn that I do not plan to heat or cool initially, but would like to insulate due to condensation issues and our hot humid climate. Have there been issues with closed cell spf in post frame buildings. My main concern would be if there ever was a screw to back out and cause a leak. Probably overthinking it, but just trying to make a decision on what makes most sense. I am also open to soffit vents and installing a ceiling and blowing in insulation.”

Screws do not “back out”. Watch a screw being driven in – it pulls the wood fibers up. Wood has an inherent “memory” and as those disturbed fibers return to their natural state, they want to pull screws in (creating even a tighter seal).

Screw leaks are caused by either poor installation, wrong placement (on high ribs rather than flats), or entirely wrong parts. Poor installation will show up right away – either in a good rain storm, or by checking weather tightness by running a water hose on roof. I would recommend second of these prior to any interior finishes.

Most of our industry uses #9 or #10 diameter screws and often only an inch long. We found, under even a small load, one inch screws will pull out of lumber – so use 1-1/2″ screws. Next issue is one of time. Eventually slots will form around shanks of #9 or #10 screws, due to cyclic loading from wind. One these slots get long enough, they extend past screw’s washers and you have a leak. We use on larger diameter screw shank diaphragm screws to eliminate this as a challenge. Many are also using screws with neoprene rubber gaskets. These are not UV resistant and will break down due to sunlight. When this occurs, you again have leaks. There is an easy solution – EPDM gaskets. Yes, they cost a bit more, however damage from a single leak outweighs any up-front costs.

If you opt for closed cell spray foam, you want to have it applied directly to inside of steel panels, with no other barrier between insulation and siding or roofing. You will need to mechanically dehumidify, as your building envelope will be air tight. Given your climate, this would be my personal choice.

An alternative would be to blow in insulation over a ceiling. You should then order raised heel trusses to attain full insulation depth from wall-to-wall. Vent eaves and ridge in correct proportions and order roof steel with an Integral Condensation Control factory applied, to avoid having drips in your dead attic space.

This entry was posted in Pole Barn Heating, Insulation, Barndominium, Pole Barn Questions, Constructing a Pole Building, Pole Barn Planning, Ventilation, Powder Coated Screws and tagged spray foam insulation, post frame screws, condensation, post frame insulation, Ventilation on May 23, 2024 by Rick Ochs.

Challenges to Insulating an Existing Pole Building

Challenges to Insulating an Existing Pole Building

Reader TODD in STACY writes:

“Hello, I am looking to insulate and heat an existing 30x40x12 pole building that was built in the mid 2000’s. It does not have soffits or ridge vents. The way it is now it gets condensation on the inside quite often just with daily weather, I assume because of the lack of ventilation. I am planning on steel liner panel ceiling, poly vaper barrier and blown in fiberglass. But the problem is how do I achieve adequate ventilation without soffits? I am worried that once i get all the insulation in and still have condensation problems and end up with wet insulation. Also, last spring, as ALL the snow from last winter was melting the water was making it up and under the roof overlaps and was freezing and spreading them open and dripping inside! Would having it insulated have kept this from happening? I couldn’t help but think it was a good thing I didn’t have it insulated then or my insulation would of been soaked! But I thought maybe it wouldn’t of happened if it had been insulated, what are your thoughts on that? When it comes the wall insulation some say to wrap everything with a house wrap from the inside, insulate with fiberglass and then poly vaper barrier and then the steel liner panel. Others say the house wrap isn’t necessary just the inside poly. What do you recommend? Thank you for your help!”

It sounds like your building has several things going on, some of them easily fixable.

If your building does not have an under-slab vapor barrier – seal it. This is your top source of moisture inside of buildings. Think of concrete as a sponge rather than a solid (concrete being actually relatively porous). Pores in concrete (smaller than human hairs. so invisible to a naked eye) constitute 12 to 18% or more of a concrete slab!

Water coming through roof steel laps…this will normally only occur if steel has been overlapped incorrectly. Smaller, or partial, rib should go over top of larger full rib. This occurs all too often, even when supposedly professional builders are hired. If this is your case, it can be remedied – remove ridge caps (number them, so they get put back in same order they came off), then remove screws closest to laps. Pull up on edge of panel currently on top. While it is being held up, pull up on other panel edge, then put full lap edge down, overlapping it with partial lap. Use screws one size large diameter and 1/2″ greater in length to refasten steel panels.

vented-closure-strip While ridge cap is off, replace solid foam closure strips with vented ones. Use 1-1/4″ long #12 stitch (metal-to-metal) screws to reattach ridge caps.

Add gable vents for air intake, bottom edge of vents should be just above thickness of ceiling insulation you will be adding. You will need to add 144 square inches of NFVA (Net Free Ventilating Area) at each end.

I am guessing your roof steel has no means of controlling condensation currently. Your easiest solve, at this point, is to have two inches of closed cell spray foam applied directly to underside of roof steel. Otherwise, you could remove entire roof and install a thermal break. Some possibilities would be reflective radiant barrier (with seams taped), metal building insulation (with seams overlapped and stapled together), or solid sheathing (such as plywood or OSB) with 30# felt applied over top.

If you can obtain it, consider blowing in granulated rockwool, rather than fiberglass, as it is not affected by moisture.

Walls – while housewrap would have been nice, rather than pulling off all wall steel, I would use rockwool batts to entirely fill cavity, well-sealed interior vapor barrier, then your steel liner panels.

This entry was posted in Pole Barn Questions, Barndominium, Roofing Materials, Pole Building How To Guides, Ventilation, Building Interior, Insulation, Pole Barn Heating and tagged insulating pole building, insulating existing pole building, insulation, closures, condensation, spray foam, Ventilation, gable vents on May 7, 2024 by admin.

Sourcing Treated Columns, Truss Bracing, and Insulating a Roof

This Wednesday the Pole Barn Guru answers reader questions about sourcing 4pc of 4x6x18′ treated columns, truss bracing in a custom cabin, and insulating a roof on a metal pole barn.

DEAR POLE BARN GURU: Looking for 4pcs 4x6x18 treated ground contact. JERRY in COATESVILLE

DEAR JERRY: This one is going to be tough. Very few lumber dealers inventory pressure preservative treated 4×6 in lengths over 16′. other than in Pacific Northwest states. For a lumberyard to bring them in, they will usually be forced to have to purchase an entire unit – not very practical for them or for you. Your solution is most likely to source 6x6x18′ as they should be in stock.

DEAR POLE BARN GURU: Trying to figure if I need more braces or not. 18 ft cathedral with king post truss. No supporting interior walls both garage below and great room are open floor plan. So I used 5/8 plywood both sides of garage walls to help with sheer wall and racking bolted everything down and now got tongue and groove on interior upstairs so should be ok . Just would like something more but maybe this enough just as it is. I got horizontal Xs up in rafter ties. I also have collar ties in peak. But other than that everything seems good I used double 2×10 for each truss from sill to peak then double 2×6 as rafter ties. BUCK in DERBY LINE

DEAR BUCK: Every bottom chord should probably be braced at centerline, not just some of them. Short of this, I couldn’t venture a guess without reviewing an entire set of structural plans.

DEAR POLE BARN GURU: After reading some opinions on some forums I am getting ready to insulate the roof of my metal pole barn. Paper backed fiberglass insulation will not stop condensation without putting plastic sheeting over top of it. How do you feel about this method? Insulation against the underside of the metal roof with plastic over the insulation. DAVE DEAR

DAVE: This should answer some of your questions https://www.hansenpolebuildings.com/2023/10/properly-insulating-between-roof-purlins/

This entry was posted in Building Interior, Lumber, Budget, Insulation, Professional Engineer, Pole Barn Questions, Columns, Roofing Materials, Constructing a Pole Building, Barndominium, Pole Barn Planning and tagged condensation, paper backed insulation, truss bracing, spray foam, treated columns, sourcing columns, insulation, king post truss on March 27, 2024 by admin.

Ballpark Figures, Blueprint Costs, and Condensation Drip

This Wednesday the Pole Barn Guru answers reader questions about ballpark figures to estimate costs of a barndominium, the costs for blueprints for a 40x60x20 building, and what the best way to stop condensation drip on a post frame building would be.

DEAR POLE BARN GURU: I’ve got a very general question, hope you can help. Is there a very ballpark figure for estimating a barndominium? As in square foot to dollars. My current house is 2500 sqtf. on two acres. I’d like less house on larger property. Currently negotiating with a friend for 7 acres. Need a ballpark figure on construction in order to decide if it’s just a pipe dream. Thanks JIM in MONEE

DEAR JIM: Thank you for reaching out to me Jim, message me any time with questions. Fully engineered post frame, modest tastes, totally DIY, move in ready, budget roughly $70-80 per sft of floor space for living areas, $35 for all others. Does not include land, site prep, utilities, permits. If you hire a General Contractor to do everything, expect 2-3x as much.

DEAR POLE BARN GURU: I’m looking to some blueprints for a 40x60x20 pole barn it will have 2 10×12 doors on the gable end wall. I want a 2 foot over hang. I want to sheet the roof with 5/8 cdx and walls with 1/2cdx. How much would the blueprints cost? MICHAEL in COOS BAY

DEAR MICHAEL: Thank you for reaching out to me Michael. Our engineers will only seal plans when we provide the materials, as it is the only way they can guarantee materials they specify will actually arrive onsite. Please send your specifics to Caleb@HansenPoleBuildings.com along with your site address and best contact number. You will find we are very competitive and have provided hundreds of fully engineered post frame buildings to our clients in Oregon.

DEAR POLE BARN GURU: Hello, I asked an insulation question on social media and it quickly turned into a debate among other members. In your opinion is there any way to stop the condensation drip on a porch we would like to cover with T/G, box in with soffits? This is a new post frame building with an offset porch. Initially we planned to leave framing exposed but due to birds and wanting a more finished look we would like to put a ceiling in place. Thank you. MEL in ISLAMORADA

DEAR MEL: As it is already existing, your quickest and easiest is to do 2″ of closed cell spray foam directly to roof steel underside.

This entry was posted in Barndominium, floorplans, Ventilation, Budget, Insulation, Pole Barn Questions, Porches, Pole Barn Design, Building Overhangs, Pole Barn Heating, Roofing Materials, Constructing a Pole Building, Pole Barn Planning and tagged condensation, spray foam, estimating a barndominium, engineered post frame home, pole barn costs, blueprints, engineer sealed plans, close cell spray foam on March 13, 2024 by admin.

What to do About Possible Roof Condensation?

What to do About Possible Roof Condensation?

Reader JEFF in ADEL writes:

“Hello, I am going to order Post Frame building materials and am working on details. The question about condensation is driving me nuts as this is a big project for me and I don’t want a wet building. It will be a 30x48x11 high side walls. 8′ on center truss/posts. No overhangs on any side Concrete floor. Not heated, not insulated and not finished inside. Location in central Iowa, I plan to wrap the walls with house wrap during build, to block wind and rain. What do I do for the roof? My worry is condensation. I have 2 neighbors that have somewhat similar builds that did nothing and say they don’t have condensation problems. My vendor offers house wrap, or a radiant barrier. What I have read says don’t use house wrap on roof because it is not a vapor barrier. I agree with that assessment. My vendor does not offer a dripstop backed steel. This condensation problem seems baffling as there is so much conflicting information and everyone you ask has a bias to sell something that may or may not work and might deteriorate and might make it worse. Am I over thinking it and should I just put up the building and fix the problem later only if I have it? Or is there a simple solution? Thank you.”

Thank you for reaching out to me. All I can say is, your neighbors have been lucky.

To begin with, I would recommend you build a fully engineered building utilizing double trusses every 12 feet rather than single trusses every eight feet.

Why?

Worst part of any building is digging holes, fewer holes means less probability of hitting a Volkswagon sized rock.

Every 12 feet, means fewer columns to set (posts are not your building’s weak link), fewer connections to be made and less pieces to handle, making for a quicker installation.

Double trusses reduce needed truss bracing, as well as creating actual physical load sharing between these two members. In event of a catastrophic snow even, likelihood of both trusses having an exact same weak point and failing is about as close to zero as one can get.

Moving forward – consider adding enclosed vented overhangs on your sidewalls (if not enclosed overhangs on all four sides). You only get a single opportunity to have overhangs. Personally, I would do without doors before I would do without overhangs. You can always add doors later, but not overhangs. Overhangs will keep your building walls cleaner, as they push rain runoff and snow slide off away from your building walls. Your building will look less industrial (better for resale) and it affords an air intake for ventilation.

Combined with a vented ridge, Hansen Pole Buildings can also provide roof steel with a factory applied Integral Condensation Control. This should eliminate all possible future roof

condensation concerns.

Extended reading on Integral Condensation Controls here: https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/

As you have deduced housewrap is wrong product under roof steel for condensation control. It does not create a thermal break – so now condensation appears on bottom of wrap, or moisture passes through and is trapped between roof steel and barrier. Radiant barriers can work – provided all seams are completely sealed. There have been issues with some brands delaminating or facing flaking off over time. This, and difficulty installing in general, are why we stopped offering them several years ago. If you build now, ignoring possible challenges, and they occur – your only practical fix is two inches of closed cell spray foam insulation applied directly to underside of roof steel. We are also finding, other than pure animal confinement structures, most post frame buildings are being insulated at some future date. It is only prudent to take steps to have appropriate ventilation, should someone later decide insulation to be a good idea.

This entry was posted in Insulation, Building Interior, Pole Barn Questions, Pole Barn Design, Building Overhangs, Roofing Materials, Pole Barn Heating, Pole Barn Planning, Barndominium, Trusses, Ventilation and tagged Ventilation, condensation control, roof condensation, house wrap, drip stop, Condenstop, condensation on March 5, 2024 by admin.

Open Cell Spray Foam to Roof Steel – When Insulation is Done Wrong

Open Cell Spray Foam to Roof Steel – When Insulation is Done Wrong

Reader JOSH in FARMINGTON writes:

“I recently had a pole barn built and after doing a lot of research, went with 5″ of open cell under the roof and on the gables. I did not have any kind of vapor barrier, as I was worried the weight of the foam would cause it to sag and create air gaps where moisture could accumulate. I checked with the metal supplier to confirm it would not cause warranty issues and they said it would not. I am somewhat 2nd guessing the open cell, but I did it because I want to make sure I see any leaks that might occur from the exposed fasteners. I have not insulated the walls yet as I wanted to get all the electrical done. My plan was I would spray low expansion foam at the top and bottom of the metal sheets because right now there are no foam seals so you can actually see daylight even with the metal rat guards. To seal these up I want to use Great Stuff Pond & Stone foam. It’s black to match the trim in case it pushes out, it’s waterproof, it’s low expansion, and it’s UV rated. Then I was going to put 1.5″ foam board between the purlins, sliding it behind the posts. Following up with covering both with another sheet of 2″ foam board and use tape at the seams and some more foam at the posts. My thought is this would create a good vapor barrier, but I’m second guessing that now. For one reason, I don’t know how I’d seal things up above the header. They used a double 2×10 on each side of the post to act as the header. I do not plan to put a ceiling up and I will have a split system with a gas furnace installed soon to keep the space tempered between 60-80. I’ll heat it up or cool it down as needed when I’m using it. Do you see any issues with this setup? I’m a little worried about not having a vapor barrier on the roof. In Arkansas, we have all seasons, but it stays pretty muggy.”

My first concern is your open cell spray foam against roof steel. You have an application here I would never recommend. Open cell spray foam allows moisture to pass through, so you are going to end up with moisture condensing on underside of roof steel. I do not have a solution at hand for this – perhaps whoever installed your spray foam has some ideas.

As you propose to insulate your walls, you are creating a vapor barrier – meaning your walls will ‘dry to inside’ – adding even more moisture to potentially cause a problem in your open cell roof insulation. I would remove steel siding from a wall at a time, then install a well-sealed housewrap. Fill insulation cavity with rockwool batts (as it is not affected by moisture), with an interior vapor barrier. Walls will now dry to outside.

Chances are you are going to need to mechanically dehumidify your building in order to minimize condensation from moisture hitting roof steel.

This entry was posted in Pole Barn Planning, Barndominium, Pole Barn Structure, Uncategorized, Ventilation, Insulation, Building Interior, Pole Barn Design, Roofing Materials, Constructing a Pole Building, Pole Building How To Guides, Pole Barn Heating and tagged open cell spray foam, condensation, spray foam, roof insulation, spray foam insulation, roof steel, moisture barrier on February 27, 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 Building Interior, Pole Barn Heating, Uncategorized, Insulation, Pole Barn Questions, Ventilation and tagged tyvek, hobby shop, insulation, vapor barrier, housewrap, condensation on February 15, 2024 by admin.

Builder Placed no Vapor Barrier Between Purlins and Roof Steel

Builder Placed no Vapor Barrier Between Purlins and Roof Steel

Almost client ALEX in CLINTON writes:

“I recently had a pole barn home built and after we moved in we discovered our roof does not have any form of vapor barrier, just metal right on top of the purlins. Our contractor stated the entire attic is heavily ventilated so the barrier was not needed, which I did not agree. After going back and forth he offered to fix it only one way. Which would be to take fanfold insulation board between each rafter. I felt this would only hide my condensation problems rather than fix it. My question is, would this be a viable option? As well I’ve looked into adding in ventilation fans in the attic to better control the moisture, thoughts on that as well please!”

Mike the Pole Barn Guru responds:

You have just hit on one of my top peeves when it comes to post frame building contractors and providers – pretending condensation is not going to occur under bare steel roofing installed directly over roof purlins.

And (even though you did not invest in a Hansen Pole Building) I have to feel we are partially at fault here.

Why?

Our mission is to assist potential clients so they avoid making crucial errors they will regret forever. In looking back through our records, when you discussed your building needs with us two years ago, we failed – we did not convey to you how important some sort of roof steel condensation control is (at least we neglected to include it in our quotes).

So now you are left with having spent a great deal of your hard-earned money (or future years of making mortgage payments with hard-earned money) and a home built almost right.

Let’s start with discussing “heavily ventilated”. To begin with, there is no realistic amount of airflow through an attic capable of eliminating all possibility for condensation. Attic ventilation systems, by Building Code, are very specific as to not only required ventilation, but also correct ratios of intake and exhaust to create proper airflow from eave to ridge. These requirements are based upon building science and studies done on actual full-sized attics. Chances are more than good, your contractor has over done either soffit intakes or ridge exhausts. He or she probably has even used vented soffit in gable end overhangs (sure to mess up proper airflow).

You can educate yourself further on ventilation requirements here: https://www.hansenpolebuildings.com/2023/06/274512/

2018 IRC Attic Ventilation Requirements – Hansen Buildings

Hansen Pole Buildings’ reader asks Mike the Pole Barn Guru how much of the ridge of a pole building ridge needs to have vented closures.

www.hansenpolebuildings.com

Attic ventilation fans, short of creating a wind tunnel, are not going to resolve future challenges.

While your contractor’s proposed solution is sort of right, it would only work if an absolute 100% air seal was achieved. Face it, this is just not going to happen.

So, what are your options?

Easiest would be to have two inches of closed cell spray foam applied directly to the underside of your roof steel.

All other options involve removing roof steel and placing a well-sealed thermal break between roof purlins and roof steel, then reapplying roof steel. Roof steel should be either shifted slightly to right or left to not place same sized screws back into same holes in wood (and original screws should not be used), or to use larger diameter, longer screws. This would be a good time to make sure replacement screws are all powder coated with EPDM gaskets.

What would give a capable thermal break?

Fan-fold insulation, reflective radiant barriers and faced metal building insulation are all possible options – provided all seams are tightly sealed. Solid sheathing roof with OSB (Oriented Strand Board) or plywood with either 30# felt or a synthetic ice and water shield between sheathing and roofing would also be a possibility.

Hopefully you have not made your final payment to your builder, so you as yet have some amount of leverage. However unless this was addressed specifically in your contract documents (we do address it in ours) chances are you are looking at some significant out of pocket expense to cure something easily and affordably solved at time of construction.

This entry was posted in Building Interior, Pole Barn Questions, Building Contractor and tagged attic condensation, attic ventilation fans, Building Code, condensation, attic space ventilation, building contractors on August 8, 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 Trusses, Ventilation, Insulation, Constructing a Pole Building, Pole Barn Structure and tagged blow in insulation, spray foam, bottom chord of trusses, insulation, vapor barrier, condensation on July 18, 2023 by admin.

Wide and Tall, Building on Slope, and a Condensation Issue

This Wednesday the Pole Barn Guru tackles reader questions about the potential wide and tall a pole building can be designed, if a pole building can be building on a slope, and how to mitigate condensation in an existing ‘horse barn’ with an open metal roof.

DEAR POLE BARN GURU: How wide and tall can a pole building be? TODD in ALLENWOOD

DEAR TODD: While clear spans of 120-150 feet are possible, from a practicality standpoint 80 feet is realistically about it. Overall building widths can be increased by utilization of interior rows of strategically placed columns. Structurally, Building Codes allow for sidewalls (at eaves) to be 40′ (or 50′ with fire suppression sprinklers). Some jurisdictions have more restrictive overall heights, so you will want to check in with your local Planning Department.

DEAR POLE BARN GURU: Can a barndominium be built on sloped land? And if so, what is your professional recommendation on how to build? Thank you! JENNIFER in BONITA SPRINGS

DEAR JENNIFER: Post frame barndominiums lend themselves very well to building on slopes. I solved a personal situation where I had 14 feet of grade change in 24 feet, by building on stilts: https://www.hansenpolebuildings.com/2022/11/what-to-do-when-the-old-post-frame-garage-has-issues/

For another building, on same parcel, I had 12 feet of grade change in 40 feet, so I excavated hillside and used ICFs (Insulated Concrete Forms) for tall sidewall and stepping down across rear endwall. This basically created a daylight or walkout. It is mentioned as part of this article https://www.hansenpolebuildings.com/2020/02/barndominium-on-a-daylight-basement/

Walkouts can be created using ICFs (as I did), poured concrete walls, or reinforced concrete block walls. With any of these, wet set brackets can be poured into tops of walls to attach building columns.

DEAR POLE BARN GURU: Hello, We’ve got an uninsulated horse barn with ‘open’ metal roof (no plywood underneath). We’re having a problem with condensation dripping ruining some of our hay. We once saw a picture of white foam guides you can staple under the rafters to guide the dripping/air outside, but can’t find a generic name, or a product name, for these guides. They are NOT an insulation product, but may be used under eaves? Do you know the name? We’d sure appreciate your help. TIM and LOUSIE

DEAR TIM and LOUSIE: This is where an ounce of prevention is worth a pound of cure. There are numerous product capable of being applied below rafters, trusses and/or roof purlins, however in order to be truly effective, you must be able to achieve a perfect seal (impossible in real life). If not, warm, moist air from inside your building is still going to rise, get through any gaps, and now be trapped with no way to escape. Even with a tight seal, unless there is a thermal break, chances are fair you will now have move the condensation from underside of roof steel, to underside of new product. There are some solutions – least expensive, highly labor intensive is to remove roof steel, install a well-sealed thermal break, reinstall roof steel or have two inches of closed cell spray foam applied to underside of roof steel.

This entry was posted in Pole Barn Planning, Pole Barn Structure, Trusses, Ventilation, Building Drainage, Insulation, Building Interior, Pole Barn Questions, Roofing Materials, Horse Riding Arena, Constructing a Pole Building, Pole Building How To Guides and tagged pole building truss span, build on slope, condensation, uneven slope site, horse barn moisture, Pole Building Height, sloped site, pole building width on June 28, 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 Barndominium, Concrete, Footings, Insulation, Rebuilding Structures, Constructing a Pole Building, Building Interior, Pole Barn Planning, Professional Engineer, Columns, Lofts, Pole Barn Homes, Trusses, Post Frame Home, Ventilation and tagged R-1, pole barn conversion, residential addition, R-III, concrete pour, insulation, vapor barrier, condensation, setting trusses, occupancy classification 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 Ventilation, Building Interior, Insulation, Constructing a Pole Building and tagged batt insulation, cold cladding, sheet insulation, Ventilation, thermal bridging, thermal break, cladding, radiant barrier, insulation, gypsum wall board, vapor barrier, convection, condensation, climate controlled on May 4, 2023 by admin.

Condensation Challenge, Adding a Garage Door, and Barn Movers

This week the Pole Barn Guru answers reader questions about likely condensation challenges with a closed envelope in coastal South Carolina, an addition of a 16′ wide garage door to an existing building, and if the Guru knows any pole barn movers in central Illinois.

DEAR POLE BARN GURU: I want to keep my building a closed envelope, for conditioned attic space. 40x60x12. My plan is to use closed cell foam 2″ on walls and 3″ on roof deck applying directly to the metal. Do you foresee any moisture issues? Environment is coastal South Carolina, Georgetown county. Hot and humid, very rare to see sub-freezing temps. Also what kind of HVAC do you recommend? RON in GEORGETOWN

DEAR RON: Unless you are going to mechanically dehumidify, expect to see condensation challenges.

Your site is in Climate Zone 3A, where the 2021 IECC (International Energy Conservation Code) specifies minimums as R-15 continuous for walls and R-49 for ceilings. You could achieve this by just over 2″ of closed cell on your walls, however you would need to add another R-28 to your roof. This could be done by adding unfaced Rockwool (Rockwool is not affected by moisture) batts between roof purlins. Specify 2×10 roof purlins 24 inches on center, then use just over 2-1/2″ of closed cell plus 23″ wide x 7-1/4″ Rockwool batts.

Your HVAC provider can recommend a system most practical for keeping humidity at manageable levels.

DEAR POLE BARN GURU: Can you add a 16 ft wide garage door to an existing pole barn? It would be on a gable end of a 30×50 building. ALEC in TOLEDO

DEAR ALEC: Probably, however it should only be done with a structural review from a Registered Professional Engineer as you would be dramatically reducing shear capacity of your endwall.

DEAR POLE BARN GURU: Do you know any pole barn movers in central Illinois? Have a 52×100 we would like to move about 15 miles, ambitious I am sure. MELANNE in DAWSON

DEAR MELANNE: If I had to take an educated guess, I would say it will cost more to move that it would to build new from scratch. At 52′ feet wide, it would take every road being at least four wide lanes between start and end of trip. You can Google “house movers near me” to see if there is anyone in your area.

This entry was posted in Pole Barn Planning, Pole Building Doors, Ventilation, Rebuilding Structures, Building Interior, Insulation, Professional Engineer, Pole Barn Questions, Pole Barn Design, Pole Barn Heating, Constructing a Pole Building, Overhead Doors, Pole Building How To Guides and tagged moisture control, condensation, closed envelope, overhead garage door, garage door, pole barn movers, moving a pole barn, closed cell spray foam on April 26, 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 Ventilation, Insulation, Pole Barn Design, Pole Barn Planning and tagged humidity, closed cell spray foam, dehumidification, flash-and-batt, Andre Omer Desjarlais, vapor barrier, condensation, fiberglass insulation on January 24, 2023 by admin.

Help! My Barndominium Vaulted Ceiling Drips

Help – My Barndominium Vaulted Ceiling Drips

Reader HOMER in PIEDMONT writes:

“I called in today and was referenced to send an email –

I have come across your website and have gained a vast amount of knowledge – I was hoping to get some more information on my situation – I also understand that you actual don’t sell insulation and that any advice you give me might not benefit your business – I am willing pay a consulting fee if you like or if i can purchase any products through your company that will help me get out of this pickle i will be more than happy to –

So my situation (the pickle)

I built a 30×60 barndominium with vaulted ceiling (the purlins on top are 8″) i used about 1/2″ to 1″ of closed cell spray foam all over it then laid the typical pink batting insulation in it – the issue I am having is I am in Oklahoma – on a morning of a cold night – when the sun comes out it heats the metal roof up and creates condensation – hence a ceiling that rains throughout the day – it seems to happen closer to the peek more than the bottom portion of the ceiling

I have tried pulling some of the batting insulation out of the middle section to help create more air space – it did seem to help a bit but still saw condensation on the spray foam insulation – when i removed my test panel (also i used 3/8 bead board for my interior sheeting)

On the peak of the roof I didn’t use the foam vent ridge cap but filled it in with spray foam (I was going for air tight) which might be more of the issue

I truly am sorry to bother you with this issue and any help or direction would be greatly appreciated – please reach out via email or phone and I am sorry if I didn’t give enough detail to paint the picture that I am facing.”

Mike the Pole Barn Guru says;

Thank you for reaching out to us. Our goal is to assist our clients from making crucial (and often costly) errors they will regret forever. While your circumstance is crucial, it can be rectified.

According to Johns Manville, a minimum of 1-1/2″ of closed cell spray foam is required in order to provide an adequate air and vapor barrier (we have always recommended two inches, as we feel it is better to be safe than sorry). Right now, the underside of your closed cell spray foam is cool enough on those cold mornings so warm moist air rising inside meets it and condenses. This is more pronounced as you approach interior peak due to warm air rising.

If it was my own roof – I would remove all fiberglass roof plane insulation, increase thickness of closed cell spray foam to at least two inches, then fill balance of 2×8 cavity with either open cell spray foam or rock wool batts (rock wool is not affected by moisture and does not lose R value during cold temperatures).

Only other possible solution (have not tried, so is only hypothetical) would be to mechanically dehumidify the interior of your barndominium to a degree low enough to eliminate your challenge. This would probably need to be under 20% relative humidity – so low as to become uncomfortable to live in (Dry, itchy skin & eyes) and causing shrinkage of wood in floors, cabinets, doors and furniture.

This entry was posted in Insulation, Pole Barn Questions, Pole Barn Design, Pole Building How To Guides, Building Contractor, Ventilation, Building Interior and tagged closed cell spray foam, rock wool insulation, pink batting insulation, condenses, condensation, barndominium on January 10, 2023 by admin.

Polyiso Pole Barn Ceiling Insulation

Polyiso Pole Barn Ceiling Insulation

Reader MIKE in OXFORD writes:

“I’ve moved into a house that also has an existing 30’x40′ (uninsulated) pole barn. I want to insulate and am considering 2″ thick polyiso foam boards attached to the bottom cord of the roof truss. The roof trusses are 4′ spacing. 1) Do you feel that is a good choice? 2) Do I need to add any type of vapor barrier (or anything else) above the polyiso boards?”

Before addressing your question, some concerns:

Does your building have some method for controlling condensation between roof framing and roof steel? This could be one of several options – well sealed reflective radiant barrier (bubble barrier) or metal building insulation, or solid sheathing (OSB or plywood) with either 30# felt or a synthetic underlayment. If not, two inches of closed cell spray foam should be applied directly to underside of roof steel. You really don’t want it ‘raining’ inside of your pole barn.

What sort of ventilation provisions are made for dead, non-conditioned attic space you are creating? Eave and ridge is best https://www.hansenpolebuildings.com/2018/03/adequate-eave-ridge-ventilation/. While Code requirements can be met with gable vents, they do not provide uniform air flow throughout area being vented.

Are trusses designed to support a ceiling load? Most widely spaced post frame trusses are designed with a minimal ceiling load – generally enough to cover weight of truss and small amounts of wiring and light fixtures. While polyiso is unlikely to create a weight overload, should you opt for other solutions, it could pose a challenge.

Some good things about polyiso insulation – at two inches thick, it only weighs 1/2 pound per square foot. Polyiso insulation delivers a high level of inherent fire resistance when compared to other foam plastic insulation due to its unique structure of strong isocyanurate chemical bonds. Polyiso has an R value of six per inch, however polyiso’s R value gets worse when it’s cold outside. Building Science Corporation’s published research shows polyiso can lose as much as 25% of its R-value when temperature drops (in general R value begins to decrease below 75 degrees Fahrenheit).

Now to address your questions:

1) If you can obtain polyiso at a reasonable price and are looking at only minimal heat retention, it might be a great solution. Personally, I would add a ceiling (steel liner panels are relatively affordable and light weight) and blow in rockwool, provided trusses are adequately designed to support added imposed weight. Adequate ventilation and a condensation control system would be a must for either.

2) A ceiling vapor barrier is only needed if your site has over 8000 heating degree days per year (only found in far northern extremes in our country). Please keep in mind, in order to function well you are not going to be able to have unsealed penetrations for wiring or light fixtures.

This entry was posted in Insulation, Pole Barn Questions, About The Pole Barn Guru, Pole Barn Planning, Trusses, Ventilation and tagged closed cell spray foam insulation, non-conditioned attic space, condensation, gable vents, polyiso, reflective radiant barrier, polisocyanurate on December 29, 2022 by admin.

Moisture Reduction, Window Sizes on a Building, and Frost Heave

Today the Pole Barn Guru addresses reader questions about moisture reduction in pole barn with dirt floor, what size windows can be added to a structure, and how to eliminate frost heave.

DEAR POLE BARN GURU: I have a 60 x 120′ pole barn with dirt floors and an insulated ceiling 18′ high. I believe the walls are also insulated but I haven’t checked. It stays very humid in there with the service door closed, which I like to do in the winter. There are 6 modestly sized windows but they’re 10′ high, hard to close in the rain and don’t ventilate much. I assume all this moisture is from the soil, is there a cost effective way to add a floor moisture barrier? ROSS in NORTHFIELD

DEAR ROSS: You are correct about where moisture is coming from – and it is made even worse in Winter, when ground outside of your building is frozen and inside your building is where all ground moisture is trying to escape (basically think of your building as being a cork pulled out of a genie’s bottle). While pouring a concrete slab on grade of a vapor barrier would be your best (and permanent) solution, concrete is costly. With this said, my best recommendation would be to remove top two inches of dirt inside of your building, making sure there are no sharp rocks projecting up above surface. Place a 15mil black vapor barrier across entire floor, overlapping seams by 12 inches and taping them tightly shut. Run vapor barrier up onto splash planks on walls (if possible) as well as sealing to each column. Cover vapor barrier with two inches of clean sand. You may need to mechanically dehumidify, in order to fully resolve your challenges.

DEAR POLE BARN GURU: Hello I am curious about window sizing in post frame buildings. Can I add any size window I want in any wall without affecting the structural integrity of the building? My largest windows are roughly 42″ wide by 64″ tall. WESLEY in DULUTH

DEAR WESLEY: Post frame buildings “work” due to their skin. Placing openings, without approval from your building’s engineer, could result in catastrophic structural failure.

For extended reading, please visit: https://www.hansenpolebuildings.com/2011/12/lateral-wind-loads/

DEAR POLE BARN GURU: The frost heave issue: how does a guy insulate his foundation? TONY in MARION

DEAR TONY: Most important for avoiding frost heave is having a properly prepared building site: https://www.hansenpolebuildings.com/2011/10/preventing_frost_heaves_in_pole_building_construction/
Here is information on insulating: https://www.hansenpolebuildings.com/2022/09/272982/

This entry was posted in Ventilation, Windows, Professional Engineer, Pole Barn Heating, Insulation, Pole Barn Questions, Pole Barn Design, Constructing a Pole Building, Pole Barn Planning and tagged frost heave, site prep, condensation barrier, moisture management, window size, wall shear, condensation on October 5, 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 Insulation, Pole Barn Questions, Roofing Materials, Pole Building How To Guides, Pole Barn Planning, Building Interior and tagged thermal break, closed cell spray foam, rock wool, PEMB, steel purlins, insulation, vapor barrier, condensation, spray foam on August 25, 2022 by admin.

My 22 Year Old Morton Building Roof Leaks

My 22 Year-Old Morton Building Roof Leaks

Reader TERRY in EVANSVILLE writes:

“Dear Pole Barn Guru, we have a 1989 Morton building. The roof was replaced in 2000 due to flaking and peeling paint. Since then, the headers over our large north and south doors have deteriorated, and the barn is leaking on the entire stretch of north and south walls further deteriorating the wood at the top and consequently the bottom as it runs down. I believe this has been happening since the roof was replaced …taking this long for us to notice the damage. I was told that there is a condensation problem. But, water runs from the ridge to the eave. We can see stains on the trusses. There are two places where water has dripped in the middle of the barn. I went up on the roof and inspected the ridge. Appears as though the ribbed metal has been over tightened about every 2 to 3 ft. in a 140 ft. span. In light rains we do not see water running down the walls, in heavy blowing storms, the water runs enough that I have videotaped it. Any words of wisdom or insight to what you think is going on would be greatly appreciated. I’ve been dealing with Morton since March of 2020 with not much success. Also, just a side note… one of their people stopped by in 2016 to look things over…at that time he said he could not adjust the doors. But…gave a $10000 estimate to rebuild, instead of looking into why there was a problem. I think if we had done the repair we would be facing a similar problem today, as the problem seems to have grown worse. Thank you in advance!”

Mike the Pole Barn Guru says:

You could have a plethora of different issues going on.

Start by process of elimination –

Is there a form fitted closure strip under each side of your ridge cap? If you have light coming through the ridge during daylight, then no. Easiest fix, if none, would be Emseal https://www.hansenpolebuildings.com/2016/03/emseal-self-expanding-sealant-tape-closures/

2) Check for leaks. Get a garden hose up on your roof – start by running water at eave lines and have someone inside yell when a leak is found. You only have to do this test on a small portion along your eave line. Pick a spot where interior water stains are greatest. Gradually work your way towards the ridge line. Leaks can usually be fixed by replacing the original screw by one of longer length and larger diameter.

3) Once the above two have been either ruled out or repaired, your problem is condensation. Stains on trusses and purlins are typically a giveaway to this being an issue, especially if they seem relatively consistent from eave to ridge and along length of building. Short of replacing roof steel with a product with an Integral Condensation Control factory applied (read more here: https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/), your solution is not inexpensive – have two inches of closed cell spray foam applied directly to underside of your roof steel.

This entry was posted in Pole Building How To Guides, Pole Barn Structure, Steel Roofing & Siding, Ventilation, Insulation, Pole Barn Questions and tagged self-expanding closures, condensation, ridge closure strips, closure strips, EmSeal, closed cell spray foam, closed cell spray foam insulation on August 18, 2022 by admin.

Insulating an Apartment in a Steel Truss Pole Barn

Reader JONATHAN in AUGUSTA writes:

“First of all, thank you for having a wonderful resource put together in one place for fellow DIYers such as myself. I am currently in the process of constructing a 30x60x11 pole barn. So far I have the roof put up; metal trusses with 2×6 wood purlins, synthetic underlayment and metal R panel. I will be building a 30×24 “apartment” inside, think box inside of a building with the remainder being used as a shop. 3 sides of the apartment will be the exterior walls of the pole barn with the 4th side splitting the barn almost in half. I will have mechanical ventilation in the form of an exhaust fan cut into the side of the building sized to the 30×36 portion with an appropriately sized louver that I intend on using when necessary when working in the shop. The apartment will have HVAC. I am looking for the best method to insulate the roof. Vented/unvented? Spray foam? Radiant barrier nailed to the bottom of the purlins? I plan to house wrap the walls and install Rockwool to insulate them but was unsure about the roof. There are so many conflicting methods out there I just want to get it right the first time. I am in a hot humid part of the south. I look forward to your thoughts on this and thank you in advance for any advice.”

Mike the Pole Barn Guru advises:

Thank you for your kind words. Obviously we are somewhat self-serving as many of our blog readers understand Hansen Pole Buildings caters to those who want to DIY and realize there is a good chance we can assist them in reaching their ultimate goals, without undue road bumps and pot holes.

You have some challenges happening here (aka pot holes), in part due to your choice of roof systems. Those trusses are not designed for a ceiling and 2×6 roof purlins at this span will deflect too far to allow for sheetrock to be applied to them, or to give an adequate depth insulation cavity.

If I was in your position, I would frame in 8 or 9 foot tall walls for apartment area, with ceiling joists above. I would then use unfaced rock wool batts between ceiling joists to R-30 (Climate Zones 0 and 1) or R-49 (Zones 2 and 3). Use 5/8″ Type X sheetrock for apartment ceiling and wall between apartment and shop (personally I like 5/8″ everywhere).

Ventilate balance of building otherwise you will most probably experience condensation challenges.

This entry was posted in Insulation, Workshop Buildings, Pole Barn Questions, Pole Barn Design, Post Frame Home, Pole Barn Planning, Barndominium, Pole Barn Structure, Shouse, Shouse, Ventilation, Sheds, Pole Barn Homes and tagged ceiling joists, condensation, type X sheetrock, Ventilation, exhaust fan, Sheetrock, unfaced rock wool batts on June 2, 2022 by admin.

Condensation Prevention, Sound Proofing, and Snow Loads

This Wednesday the Pole Barn Guru tackles reader questions about condensation prevention by placing foam board over the top of 2×4 purlins, options for sound proofing a post frame home, and if 2×4 flat purlins can hold a specific snow load.

DEAR POLE BARN GURU: I am planning a pole barn; the roof will have 2×4 purlins spaced 24″. I plan on putting 1/2″ foam board (faced on both sides) over the purlins with the seams taped. Then putting metal panels over the foam board. Will this be sufficient to prevent condensation from dripping within from the roof? JIM in MIDLAND

DEAR JIM: Good news and bad news…. while your proposed solution will likely take care of possible condensation issues, it is structurally unsound. Post frame (pole barn) buildings rely upon shear strength of steel roofing and siding in order to remain stable. When you add in even a half-inch gap of non-rigid material (foam board) between framing and steel skin, you greatly reduce (or eliminate) shear strength of your steel panels. Even if your building were to remain standing, shifting of steel panels with small diameter (#9 or #10) screws will cause slots to form around screw shanks, eventually causing leakage.

You would be best served to order roof steel with an Integral Condensation Control (read more on I.C.C. here https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/) factory applied. It will be less costly, easier to install and not cause negative structural issues.

DEAR POLE BARN GURU: Afternoon! Thanks for all the great info in your blog. It has really helped me plan my new home. I have one question: I’m having a post frame home built and am wondering about soundproofing. The roof(s) will be steel directly on purlins with a radiant barrier in between. The conditioned space will have R-60 blown-in fiberglass above it so I’m not worried about that. What I am concerned with are the front and rear porches. The front will have a, 8″ shed roof porch and the rear will have a 16×16 gable-roof screened porch. Both will have finished ceilings, steel and knotty pine respectively. I’d like to be able to sit under either when it’s raining and it not be loud. What would you suggest I do to mitigate the drum effect in an uninsulated porch? I’ve thought about using rockwool batts, maybe mass-loaded vinyl, or even painting the underside of the steel with liquid rubber before the panels are screwed down. Any advice? Thanks much. PETER in HUDSON

I am pleased my information has proven helpful to you. I would consider one of two options – installing steel in these two areas over solid sheathing (OSB or plywood) with 30# felt or a synthetic underlayment, or using two inches of closed cell spray foam applied directly to underside of roof steel. Either of these should assist in mitigating sound.

DEAR POLE BARN GURU: In an area with a 50 p.s.i. snow load ground rating and trusses 4′ o.c., can 2×4’s 2ft. o.c. be laid flat for roof purlins? STEVE in WYOMING

DEAR STEVE: Maybe – this will depend upon numerous factors including (but not limited to):

Risk Category of building
Roof slope
Wind Exposure
Roofing material
Snow retention systems
If building is heated or not
Available grade of lumber

Ultimately this decision should be made by whomever your engineer is who is sealing your building plans. Special care should also be taken to insure adequacy of purlins in drift zones (closest to ridge), where purlins may need to be closer spaced, higher grade and/or larger dimension material.

Also – ground snow loads (Pg) are typically expressed in p.s.f. (pounds per square foot), rather than p.s.i. A p.s.i. of 50 would equate to 7200 p.s.f

This entry was posted in Professional Engineer, Insulation, Pole Barn Questions, Pole Barn Homes, Pole Barn Design, Roofing Materials, Post Frame Home, Constructing a Pole Building, Barndominium, Trusses, Ventilation and tagged purlin spacing, snow loads, drip stop, condensation, condensation prevention, OSB roofing, spray foam, steel over OSB on June 1, 2022 by admin.

Pool Inside Pole Barn

Pool Inside Pole Barn

Reader DOUG in SNOHOMISH writes:

“I am just starting the process of having an inground swimming pool installed but due to weather and TREES in my area I have decided to build a Pole Barn to enclose the entire pool. I have done a lot of research on Pools and Pole Barns over the past 2+ years before coming to this conclusion. With advice from you and a ex-framer brother I feel that this is the right direction based on cost and complexity level.

What I am missing is real details and examples of individuals that have done similar projects. I could ask a million questions and spend days just chatting to you and/or other experts but it is unlikely I would be allowed. ☹ I have been searching the web for examples with more details on the different phases of the construction such as (1) Insulation, (2) Framing Walls, (3) Drywall, (4) Ceiling, (5) HVAC D, (6) Electricial, (7) ETC… but have not found much. Is there any good information on such projects being undertaken by experienced DIY individuals? (I know what you are thinking DIY = Don’t Indulge Yourself, but in this case I really am an Experienced DIY, having BUILT my own 4700sf home including either GC or hands on.

I am really considering using a Hansen Pole Barn Kit for the shell, but need to figure out how to ensure 60% humidity inside the building doesn’t rot it from the inside out. I know that HVAC Dehumidification will be very import, but so is how to seal the build walls from both the outside and inside, how to insulate the walls and ceiling (especially since we plan to have a flat ceiling thus an attic area where the Ceiling and Roof may need to both be insulated to avoid condensation, etc.

Any advice and especially great examples with details would be appreciated.”

Mike the Pole Barn Guru says:

It has been several years since we provided one of our buildings over a pool. Here is an article I wrote as a result of it and a more recent inquiry: https://www.hansenpolebuildings.com/2019/08/post-frame-indoor-swimming-pool-considerations/

Obviously your key to success is having a great HVAC/R system.

I do try to always err on caution’s side.

Adding to my referenced article above – I would add using all rock wool insulation as it is unaffected by moisture. Have a Weather Resistant Barrier between framing and wall steel (allows water vapor to exit the wall). Consider finishing the interior with cement board over a well-sealed vapor barrier, rather than “green board” moisture resistant drywall. Cement board is comparable in weight to drywall, so will not require adding to structural capacity beyond what sheetrock would take. Have a well ventilated attic (eave and ridge).

You will want to seal the interior – walls and ceiling, while having the exterior able to allow any moisture to escape.

Electrical is outside of my wheelhouse, otherwise you should be “good to go”.

This entry was posted in Pole Barn Questions, Pole Barn Design, Pole Building How To Guides, Pole Barn Planning, Ventilation, Building Interior and tagged electrical, indoor swimming pool, insulation, condensation, drywall, HVAC on March 24, 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 Ventilation, Concrete, Pole Barn Questions, Pole Barn Homes, Pole Barn Design, Building Styles and Designs, Building Department, Post Frame Home, Constructing a Pole Building, Barndominium, Pole Barn Planning, Shouse, floorplans and tagged post frame floor plans, post frame building permit, moisture barrier, Post Frame Home, shouse, vapor barrier, condensation, barndominium plans, Building permit on March 23, 2022 by admin.

When the Problem is Not the Problem

When The Problem, Is Not The Problem

Captain Jack Sparrow’s quote is close in this instance. Please read on…..

RYAN in MISSOURI writes:

“Hi Mike – I spoke with Brenda at your office and she said you may be willing to help me out. I don’t expect you to just give me free advice though, so if you were willing to provide me with some feedback on my “project”, I would like to pay you via Venmo or maybe your office could work up an invoice and I can pay you guys with a credit card.

I built a 36×48 pole barn 5 years ago and didn’t account for adequate ventilation and now I want to fix the problem (I’m sure you’ve heard that line countless times before). I read one of your blog posts to get a head start on working up a plan of attack to keep it dry in there. I’m hoping you could check my work and either take a phone call from me or provide guidance via email (again, I can shoot you some money for this, please just let me know what sounds acceptable to you).

Specs on the barn (I’ve included some older pics from before I installed the gutters and the electric below):

Location: central Missouri

Dimensions: 36′ wide (gable and door end) x 48′ long

No overhangs or soffit

Two 8 ft ridge vents

Gutters down the eave/length sides to push water away from the “foundation”

Currently no vents on the eave/length or gable sides or anywhere really… just some gaps around the trim and the base of the building where you can see daylight.

The barn has electricity and the floor is just gravel. I have a junction box run to the gable on the south side (over the door ready to accommodate a vent fan). No animals inside. Just old tractors, some tools, and four wheelers. I don’t plan on putting in concrete or any HVAC. Things out there can get hot or cold, I just don’t want it raining from the ceiling anymore.

Using your blog post, I tried to calculate what I would need as far as the CFM rating of the fan and the square inches of vent space (table of numbers below)

Questions:

Before installing a fan, I should ask: is a fan even necessary? Seeing as I don’t care about HVAC, temperature or even critters getting in there, could I get by with just strategically placed vents and wind?

If I do need a fan to generate enough circulation, does my math below look ok?

Would the Airlift T16 with a 3060 CFM adjustable fan speed and a humidity detector or something like it work ok?

Where would you recommend I place the vents (and I’m happy to go overkill on them if needed) in order to achieve the best results?

Thank you so much for your time!”

Mike the Pole Barn Guru writes:
Thank you for your generous offer of payment Ryan, however I answer all sorts of similar questions for free.

Now, the good news and bad news….

Good news is you do not have a ventilation problem, no reason to invest in any possibly expensive power ventilator fans.

Bad news – as you have found out, it rains from your ceiling. What you have is a condensation problem. Warm, moist air inside of your building is rising. It contacts with cooler roof steel, condenses and rains. This is much easier solved at time of construction than now (as well as less expensive). Roof steel ordered with an Integral Condensation Control factory applied would have been highly affordable, as well as easy to install.

Short of removing and reinstalling your roof steel to add a thermal break between purlins and steel (both costly and labor intensive), I would recommend having two inches of closed cell spray foam professionally applied to the underside of your roof steel.

When you do pour a concrete slab inside, be sure to add a well-sealed 6mil or thicker vapor barrier underneath.

This entry was posted in Pole Barn Questions, Steel Roofing & Siding, Ventilation and tagged ventilator fans, pole barn, condensation, Ventilation, thermal break, closed cell spray foam on March 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 Constructing a Pole Building, Pole Building How To Guides, Ventilation, Concrete, Building Drainage, Building Interior, Pole Barn Questions, Building Overhangs and tagged soffit vents, exhaust fan, vapor barrier, condensation, Concrete, ridge vent 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 insulation, vapor barrier, condensation, commercial girts, house wrap, IECC, craft backed insulation, EPS Insulation sheets on January 13, 2022 by admin.

My Barndominium Attic Has Moisture Issues!

My Barndominium Attic Has Moisture Issues!

Reader DAVID in CHICAGO writes:

“Greetings – I’ve got a pole barn style home that’s about 2.5 years old and I’m having moisture issues in the attic. Hoping I can talk with someone to get a consult or second opinion to resolve as quickly as possible. Let me know if it is something you can connect on. Attached is an image from the attic where you can see moisture on the underside of the metal roof. It freezes at night and then during the day when the sun is out, it melts and drips into the attic insulation.

Attic space is dead, image below. Vented through passive soffit vents and ridge vent, with a few solar blaster ridge vents to help with active venting when the sun is out. Attic insulation is R50 blown in at 20 inches deep. Image of exterior attached. It’s sheet metal that’s then spray foamed on the inside and additional R25 batts. Image below from when we had this same issue earlier this year in February 2021 when the drywall walls and ceilings had to be torn out due to water damage. We purchase in January 2021 and the home is now 2.5-3 years old. There is a solid concrete slab that has in-floor heat. I believe it has a vapor barrier underneath from an image I saw. “

Mike the Pole Barn Guru writes:
You are victim of what is such a simple and economical solution, when planned for in advance. Why builders and building providers fail to address steel roof condensation initially drives me to consider alcoholism!

I do realize they are just ‘selling on a cheap price’, rather than providing a best solution for their client.

Easiest solve is to have two inches of closed cell spray foam applied to underside of roof purlins. Any other solutions will take removal of roof steel panels, adding a thermal break, and then reinstalling roofing.

At time of construction I would have recommended roof steel with an Integral Condensation Control (ICC) factory applied. Investment then would have been a fraction of having to solve it now.

For extended reading on ICCs https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/.

This entry was posted in Pole Barn Homes, Insulation, Post Frame Home, Pole Barn Questions, Pole Barn Planning, Barndominium, Shouse, Ventilation and tagged barndominium, integral condensation control, closed cell spray foam insulation, condensation, metal roof, R50 attic insulation, metal roof condensation, ridge vent on January 6, 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 eaves, girts, NFVA, purlins, gable vents, Prodex, spray foam insulation, Ridge cap, vapor barrier, barndominiums, condensation, net free ventilation area on December 16, 2021 by admin.

Barndominium Closed Cell Spray Foam

Barndominium Closed Cell Spray Foam – and Rodents

Closed cell spray foam applied directly to steel roofing and siding can be a great product for controlling condensation, achieving an air tight barndominium and at R-7 per inch is a great insulation solution. So good, I strongly encourage its use, especially for those buildings in Climate Zones one and two (deep South).

One thing it does not do is to prevent mice, rodents and other similar pests from enjoying your comfortable living spaces.

It’s important to understand what it is inviting critters in to begin with.

Where your barndominium has most air leaks is where rodents, bats and bugs come in through. Usually this is poorly detailed and installed steel trims.

When these pests are looking for a nice, comfortable place to stay, they are going to run along outside barndominium’s exterior until they find an opening. Basically, these rascally little rodents are looking for air movement out of your barndominium.

If it’s cold outside and your barndominium is leaking heat, a mouse is going to find those leaks and consider it as a warm invitation in!

Seal up any openings where these critters can get into your barndominium, especially if you notice openings in your roof or along wall steel base. Those are issues you’ll want to take care of right away.

Once this is done, adding closed cell spray foam insulation can help.

Spray foam offers no food value to rodents or pests.

Good thing about closed cell spray foam when it comes to pests is it does help to seal up those cracks and crevices where it is sprayed, making it more difficult for those unwanted guests to get inside. This is because closed cell spray foam creates an air seal keeping inside air where it belongs.

As creatures search for drafts coming from your barndominium, closed cell spray foam’s air barrier leaves nothing for those varmints to find.

Closed cell spray foam insulation is in no way a repellant. As mice, bats, rats, and other pests can chew through wood to get into and out of your barndominium, they can of course chew through closed cell spray foam.

Closed cell spray foam insulation in your barndominium can definitely help keep pests out as it provides a defensive layer to keep pests out by blocking those air leaks they are looking for.

This entry was posted in Post Frame Home, Insulation, Constructing a Pole Building, Barndominium, Pole Barn Planning, Shouse, Ventilation, Pole Barn Homes and tagged closed cell spray foam, closed cell spray foam insulation, insulation, air movement, condensation, barndominium, rodents on December 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 Planning, Ventilation, Pole Barn Heating and tagged air exhaust, vapor barrier, condensation, Ventilation, gable vents, Ridge cap, exhaust fan, air intake on October 29, 2021 by admin.

Cupola Sizes, Insulation for a Ceiling, and Structural Pieces

This week the Pole Barn Guru tackles reader questions about cupola sizes, the proper way to insulate a shed ceiling, and a structural materials question.

DEAR POLE BARN GURU: What base size and height is correct for a cupolas for a 32’ wide by 36’ long by 35-40’ high with a 10 over 12 pitch roof? Thank you for your answer. NANCY in SPENCER

DEAR NANCY: This may answer some of your questions: https://www.hansenpolebuildings.com/2015/09/cupola/. As to actual height of your cupola(s) – this is totally subjective based upon what you feel looks best.

DEAR POLE BARN GURU: I’m desperately trying to figure out the proper way to insulate my pole shed ceiling. The Purlins run parallel rather than peak to eves. And there are no soffits or vents to be had. I have metal roofing with fiberglass roll insulation between roofing and purlins that has the vapor barrier backing. I’m afraid to slice holes in this vapor barrier as it may cause the metal roofing to condensate. My purlins are conducting cold temps in winter and when the heat hits them, they grow mold in some places as they’re very cold – or hot in the summer. Can I install the paper back fiberglass between purlins and be okay? I’m hoping would slow moisture down. but allow it to dry as well. IDK I’m in the NW mountains of Oregon, we do get low temps and snow and the shop is mildly heated in winter. I can’t afford to redo the roof or go with blown in foam. Is there another way? Can I use fiberglass batting safely? My end goal is to have tin roofing on the ceiling, is that okay? Sorry to bother you with such a common question but I haven’t found anyone with my exact issue. Thanks so much for your time and I sincerely hope to hear from you, big fan, DAVE in GALES CREEK

DEAR DAVE: Appreciate your being a big fan – thank you!

No, you cannot/should not install paper (kraft faced) backed fiberglass insulation between your building’s roof purlins. This would create a system with two vapor barriers, trapping moisture between them. Start by looking to what is probably your source of moisture – your concrete floor. If you do not have a well-sealed vapor barrier underneath it, use a sealant on top of your concrete to reduce moisture coming up through your slab. After you have your steel ceiling in place, blow in fiberglass insulation above it, and install vents in each gable end and under your ridge cap.

DEAR POLE BARN GURU: What is the type of steel (cold roll, stainless, etc.) used and the thickness of the trusses and main poles holding the structure up. ERIC in PAHRUMP

DEAR ERIC: 40 years ago I provided a post frame building kit package for a tire dealer in Pahrump!

Most steel roofing and siding is cold roll formed. These panels most typically have SMP paint (https://www.hansenpolebuildings.com/2014/05/smp/) over a galvanized or galvalume substrate. There are Building Code minimum requirements for residential steel roofing substrates (https://www.hansenpolebuildings.com/2020/11/minimum-steel-substrate-coating/). Hansen Pole Buildings use two-ply (for interior spans) 1-1/2″ width (2x lumber) chords and webs for prefabricated roof trusses, assembled with 16, 18 or 20 gauge galvanized steel pressed in connector plates. Plate thickness is determined by truss engineers to meet tension requirements. Main roof supporting members may be either glulaminated or solid sawn timbers, depending upon eave heights, roof slope, applied wind and/or snow loads, dead weight of roof assembly and availability of materials in a given market. Actual sizing will be determined by our third-party engineers.

This entry was posted in Insulation, Trusses, Pole Barn Questions, Ventilation, Pole Barn Design, Building Interior, Building Styles and Designs, Roofing Materials, Constructing a Pole Building, Professional Engineer, Pole Building How To Guides, Pole Barn Structure, Lumber and tagged condensation, roll form, ceiling insulation, roof condensation, cupola, trusses, cupola sizes, cupola base, insulation, steel rolls on October 25, 2021 by admin.

How to Insulate a Post Frame Shop

How to Insulate a Post Frame Shop When No Advance Considerations Were Made

I encourage clients to give some serious advance consideration when erecting new post frame (pole) buildings to any eventuality of future climate control and a need for insulation.

Reader MAC in MILLVILLE writes:

“40 x 30 want to insulate. It will be used as a storage/workshop. I included pictures so you can see what I have. What’s the best way to insulate? I plan on doing metal ceiling liner and most likely plywood on the walls. There is no vapor barrier under the concrete either. I do have a vented ridge and soffit. I hope I provided enough information to be able to answer my question.”

Start by sealing your concrete floor – as this is going to be a moisture source you do not want inside of your new building.

Roof/ceiling – no provision has been made to prevent condensation from happening beneath your roof steel. Sadly I see this occur far too often, as builders, kit providers and local lumberyards just lack knowledge needed to be able to educate and make best recommendations to their clients. You could either (a) remove roof steel, add a method of condensation control (such as a Reflective Radiant Barrier or sheathing such as OSB or plywood with either 30# felt or a synthetic ice and water shield) and reinstall steel using new, large diameter screws. This is highly labor intensive and your roof may not have been designed to support the weight of adding sheathing.

Best solution will be to have two inches of closed cell spray foam applied to the underside of roof steel at roughly two dollars a square foot. Not an inexpensive solution when its need could have been prevented with better advice up front.

Cumberland County is in Climate Zone 4A, as such you should have a minimum of R-49 ceilings and R-20 walls. Perimeter of your slab should be insulated two feet deep with R-10.

I would dig a trench two feet deep around your building, up tight to its pressure preservative treated splash plank and install R-10 rigid board XPS insulation from the height of the top of the slab down two feet. Install a metal, cement board, or cellular PVC panel to conceal any insulation portion left exposed above grade. If cement board is used, it should be a type not reinforced with wood fibers. Install a metal cap as an insect guard to conceal the top horizontal edge of both insulation board and closure panel. Seal cap to splash plank with mastic.

Once you have a ceiling liner in place, blow in R-49 or greater thickness of fiberglass insulation.

For walls, I normally like to see a Weather Resistant Barrier (like Tyvek) between framing and siding. As you do not have this, I would use R-21 unfaced Rockwool stone wool insulation, as it is not affected by moisture. Place a well-sealed 6mil clear plastic vapor barrier over the inside of insulation prior to placing plywood on walls.

This entry was posted in Concrete, Workshop Buildings, Insulation, Pole Barn Questions, Roofing Materials, Pole Building How To Guides, Pole Barn Planning and tagged sealing concrete floor, closed cell spray foam insulation, rock wool insulation, concrete floor seal, metal ceiling liner, rigid board XPS insulation, cement board, insulation, cellular PVC panel, condensation on September 15, 2021 by admin.

Proper Ventilation, Condensation Control, and Post Treatment

This week the Pole Barn Guru answers reader questions about ventilation, how to control condensation on fifteen year old building, and best practices for treated posts in ground or on specialty brackets.

DEAR POLE BARN GURU: I have a barn that doesn’t have soffit vents but it does have a ridge vent. I installed reflective insulation which seems to have dropped the temperature quite a bit. I also have a gable powered fan that does 2000 CFM. However it is about 8 to 10 feet lower than the ridge vent. Are these two things fighting each other do you think or should I take a pipe and vent it up to my ridge vent and to my fan to take the hot air out from the top or should I turn my gable fan off completely.
I could always try to install some soffit vents as well. KEN in GREENVILLE

DEAR KEN: Your ridge vent is a natural air exhaust point, as warm air will rise and exit through it. Any vents lower in your building should be air intakes (whether gable or soffit vents) and ratio of net free ventilation area between the two should be roughly equal (intake can be up to 10% greater area than exhaust, but should not be greater).

DEAR POLE BARN GURU: I have a 30x56x10 Menards package with the inside finished off with drywall built 15 years ago. The roof was installed without any condensation control to the underside of the steel. The amount of condensation this past year created truss heave. All ceiling penetration’s are sealed and fiberglass blow in was installed to a r49 rating. what would be the most effective way to eliminate our condensation issue? Thank you for your time and knowledge. LOUIE in AMBOY

DEAR LOUIE: Drives me absolutely bonkers when providers or builders make no true efforts to advise customers on perils of condensation and how to prevent it. So easily, and inexpensively, done at time of construction.

Have two inches of closed cell spray foam applied to the underside of your roof steel. Make sure your dead attic space is adequately vented, ideally with soffit vents and ridge vent, or (if no sidewall overhangs) gable vents and ridge vent. If you do not have a vapor barrier under your concrete slab, apply a high quality sealer to it.

DEAR POLE BARN GURU: What are the pro’s and con’s for 6″x6″ posts to be set on a drilled whole with footer at the base then back filled VS drilled whole with footer poured to grade and using CBS/CBSQ column bases that are submerged into the footer while pouring so the 6″x6″ can be above grade.

Column bases are made by Simpson Strong-Tie on page 76 and 77 they also come in stainless steel. I attached the Simpson booklet for you to see the Column bases, I’m looking to build a 40’x40’x14′ pole barn with gable roof, one man door, 16′ wide x 13′ high insulated garage door, and a cement floor. I live in North East Ohio so I get a far amount of snow load.

Kind regards, DENNIS in CHESTERLAND

DEAR DENNIS: Properly pressure preservative treated columns, embedded in ground are unlikely to decay within lifetimes of anyone alive on our planet today https://www.hansenpolebuildings.com/2020/09/pressure-treated-post-frame-building-poles-rot/.

Simpson brackets you reference are not designed to withstand moment (bending) loads, just uplift and downward (gravity) loads. If your concern is properly pressure preservative treated columns will decay prematurely and do not want wood in ground, we can furnish your building kit package with Code compliant brackets and properly engineer concrete piers. Bracket mounting will increase your investment, somewhat, however if it results in your sleeping better at night, then they are well worth it.

This entry was posted in Pole Barn Questions, Pole Barn Planning, Pole Barn Structure, Ventilation, Footings, Columns and tagged reflective radiant barrier, roof condensation barrier, exhaust fan, in ground post treatment, condensation, pressure treated posts, Ventilation, Post brackets on September 13, 2021 by admin.

Condensation Issues, Adding a Loft, and Metal Truss Load

This week the Pole Barn Guru discusses issues with condensation in a new building, advice for adding a loft, and achieving a roof load for prefabricated metal trusses.

DEAR POLE BARN GURU: Hello, I have a new construction pole barn that I recently had put up. The building is used to primarily house animals. When I had it put up I was told I would have to condensation issues with eave vents and a ridge vent that would extend the whole length of the building. The dripping really bothers me and I was wondering if there is a good option of putting a barrier of some sort on the bottom side of the purlins? My rafter spacing is 8ft. THOMAS in NEW SALEM

DEAR THOMAS: In most instances eave and ridge vents are inadequate alone to prevent condensation. Contractors who fail to include some sort of thermal break between roof framing and roof steel are doing a severe disservice, in my opinion. It is so easy to accomplish at time of construction with products such as a Reflective Radiant Barrier or Integral Condensation Control. There is not a good option for an underside of purlins vapor barrier, as it is nearly impossible to adequately seal it. Your only real solution, at this point, would be to use two inches of closed cell spray foam on underside of your roof steel.

DEAR POLE BARN GURU: My wife and I are building our post frame building ourselves. We’re building a loft living area on 1 end which I’m using 11.875 x 2.5 x 20′ long I-joist 16″ center.

My question is, My 6×8 posts are 8′ centers, can I attach a single 2x12x8′ between these posts and attach the I joist hangers to this to support the floor or will I need to double them like a header?

Thank you ALLAN in FORT ATKINSON

DEAR ALLAN: Any lofts, second or third floors being added to post frame buildings should only be done so under design of a Registered Professional Engineer – ideally whomever was Engineer of Record for your original sealed building plans. Rarely do concrete footings below building columns have adequate thickness or diameter to support additional loads being implied to columns. In most instances, beams for support of floor joists, I joists or prefabricated floor trusses will be limited in capacity by deflection, rather than ability to carry a given load. I can guarantee a single 2×12 is inadequate to support your I joists.

Your engineer will also determine proper number and size of fasteners to support beam to column attachments. At a minimum, with a 50 pound per square foot total floor load, columns every eight feet and a 20 foot span, each connection must support 4000 pounds of load.

Please, I implore you, do not attempt this floor design without proper engineering guidance – it could be lifesaving.

DEAR POLE BARN GURU: We are building a pole barn that is 20 by 32 with 8ft spacing. We are using steel trusses for this project, but our roof load for this county is 120lb per square ft., so how do I achieve this or how many trusses I would need to put in? Any help would help thank you. CHRIS in EMMETT

DEAR CHRIS: You should reach out to whomever provided your trusses to get an engineered repair. You should be able to have additional members welded onto what you have in order to meet required loads. On larger spans, this type of repair might not be possible.

This entry was posted in Trusses, Ventilation, Building Interior, Lumber, Columns, Pole Barn Questions, Pole Barn Design, Lofts, Constructing a Pole Building, Pole Barn Planning and tagged registered design professional, ridge vent, reflective radiant barrier, loft, condensation, gable vent, A1V, I-beam on July 12, 2021 by admin.

Roof Sheeting, Blueprints, and Condensation Control

Today the Pole Barn Guru answers reader questions about adding sheeting and tar paper to a metal roof, if we could supply blueprints for project 08-0602, and condensation control for a tight structure.

DEAR POLE BARN GURU: Can most pole building metal roofs support the extra weight of sheeting and tar paper (underlayment)? TAMI in SCOTTSDALE

DEAR TAMI: Most pole building roof systems are designed to support a bare minimum roof dead load – usually 2.5 to 3.3 psf (pounds per square foot). If this is your case, then your structure would not be able to support this added weight. We made a decision a year ago to use a minimum top chord (roof) dead load on all our roof trusses spanning 40 feet or less of five psf – just in case our clients decided to sheet their roofs with OSB or plywood with an underlayment and didn’t tell us about it in advance.

DEAR POLE BARN GURU: We want to build a pole barn 48×60 feet, like the Hansen building: Project# 08-0602 in Decatur, AL. Is there an existing blueprint we could use to built the structure and see all the bearing poles with all the dimension? We will have a designer to create the inside of the building. Are there some existing construction plans with detailed planning?
Nive Regards, PETRA in GREENBRIER

DEAR PETRA: Thank you for your interest in a new custom designed, fully engineered Hansen Pole Building. While we, of course, have in our records engineered plans for this structure. Due to differences in Building Code versions (referenced building was under 2006 Codes), and variations in design snow and wind loads, we would furnish an updated structural set of blueprints with your investment in your new building. These plans detail out locations and connections for every structural component of your building.

DEAR POLE BARN GURU: I have a 24×40 barn (steel sides, shingled/sheathed roof, concrete floor) that I’ll be heating. Walls and ceiling will have fiberglass batts insulation along with a vapor barrier on walls under OSB sheathing. OSB on ceiling as well. A buddy of mine caulked all his OSB joints then painted (latex) walls and ceiling in an attempt to further improve heating situation. In other blogs/questions you’ve answered with similar setups you talk about the importance of vapor and/or heated air needing to escape through ceiling into attic to help get rid of moisture. Will caulking and painting walls and ceiling limit the proper venting of moisture vapor from escaping my heated barn? JOHN in RICHLAND

DEAR JOHN: When buildings get so tight, it becomes necessary to use mechanical dehumidifying in order to prevent condensation challenges. For a barn, this might prove to be a greater investment than you wish to undertake.

Provided you have either no vapor barrier, or a Weather Resistant Barrier directly beneath your steel siding, if you caulk and paint interior walls, no vapor barrier and unfaced insulation will probably be more than an adequate design solution. You may want to consider rock wool batts as you are likely to have some condensation on inside of wall steel and fiberglass loses performance and can be prone to mold once it has gotten wet.

This entry was posted in Ventilation, Building Interior, Professional Engineer, Insulation, Pole Barn Questions, Pole Barn Homes, Roofing Materials, Constructing a Pole Building, Post Frame Home, Pole Barn Planning and tagged insulation, tar paper, condensation, roof dead load, blueprints, roof sheeting, monitor buildings on May 10, 2021 by admin.

Insulation Option, Condensation Control, and Plans Only?

Today’s Pole Barn Guru answers reader questions about adding a styrofoam insulation board to help keep a pole barn warm, how to best prevent condensation, and if one can purchase plans only instead of the complete kit.

DEAR POLE BARN GURU: I recently built a pole barn, I’m in Ohio. I put in a 15000w electric heater, it does an ok job as long as it’s not 20 degrees out. My question is, can I use styrofoam insulation board that is 1″ think for insulation on the trusses? I have a condensation layer on the roof metal. I’d like to start somewhere and I thought this would be least expensive. Thanks. TERRY in CARROLL

DEAR TERRY: If “on the trusses” is in reference to across truss bottom chords, chances are good your trusses can support their weight if your insulation board is polyisocyanurate. Polyiso weighs in at roughly 0.25 pounds per square foot per inch of thickness. An inch of polyiso provides an in service R value of roughly 5.6. Polyiso insulation may need to be fire or flame spread protected, by Building Code – you will want to consult with your local Building Official, prior to moving forward. Adequate ventilation must be provided for your dead attic space (read more about ventilation requirements here: https://www.hansenpolebuildings.com/2018/03/adequate-eave-ridge-ventilation/)

DEAR POLE BARN GURU: I’m working on building a 30×40′ post frame building for storage/ garage and workshop and I live in Kansas so it’s cold in the winter and humid in the summer so I have concerns about condensation. I’ve looked into the single and double bubble foil insulation products and just the foil sheets for thermal/ condensation and the condensation blankets.

I plan to eventually insulate the walls and heat with a wood burning stove and just open the garage doors and turn on a fan in the summer. When I pour my slab I have 10mil vapor barrier that will go down on the ground.

What would be my best budget option to help control condensation and insulate some? JOEY in ANDOVER

DEAR JOEY: I will do my best to balance ‘best’ and ‘budget’.

Kudos for use of a under slab vapor barrier thicker than 6mil. My typical recommendation is 15mil, but 10 is certainly a step up. Make certain overlaps are well sealed and run it up inside and onto top of your pressure preservative treated splash planks (bottom girt).

Walls – use a well-sealed Weather Resistant Barrier (WRB) between framing and steel siding. Read more about WRBs here – https://www.hansenpolebuildings.com/2016/01/determining-the-most-effective-building-weather-resistant-barrier-part-1/. Frame walls with commercial bookshelf girts (https://www.hansenpolebuildings.com/2011/09/commercial-girts-what-are-they/). Install unfaced fiberglass batt insulation between girts, with a well-sealed 6mil clear visqueen vapor barrier on inside.

Roof – order roof steel with an Integral Condensation Control factory applied (https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/). Roof trusses should be ordered with raised heels two inches greater in height than thickness of blown in fiberglass attic insulation (https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/) and attic adequately ventilated with vented soffit panels at eaves and a vented ridge.

DEAR POLE BARN GURU: Good Morning, Can I just order the plans for a pole barn instead of the full building kit? TANNER in BOWLING GREEN

DEAR TANNER: Thank you for your inquiry.

Hansen Pole Buildings are carefully designed and engineered to exacting and stringent standards. Included with these structural design solutions are some components an average individual cannot just go buy off a shelf at your local lumber dealer or big box store. Due to liability issues with materials specified on plans not being able to be readily acquired by general populace members, our third-party engineers are unable and unwilling to put their seals and signatures on plans where we are not providing components. Even if they were to do so (and you could find parts as specified) we have so much buying power, we are able to provide materials at a price level competitive to anything you would be able to acquire on your own.

This entry was posted in Budget, Professional Engineer, Lumber, Pole Barn Heating, Insulation, Pole Barn Questions, Pole Barn Planning, Ventilation and tagged Ventilation, engineered pole building plans, pole barn heating, insulation, condensation on April 26, 2021 by admin.

Solving Horse Barn Condensation Challenges

Proper ventilation of horse barns is essential to good equine health. Reader DONN in LONGMONT writes:

“Hi, last summer I added 8 more horse stalls to our existing horse barn. There was a lean-to already attached that I extended on to and enclosed. The horse stalls are approximately 12’x12′ and a 10′ wide walkway that is poured concrete. The entire footprint is, 100′ x 24′.The ceiling height is approximately 12′ tall at the original barn and 7′ tall at the west end for fall. 2 sliding doors to bring horses in and out on the north & south ends and 8 windows on the west side that are 3′ x 4″. I insulated the walls & ceiling with 6″ batt insulation then drywall and painted. I started having condensation issues with water getting into the drywall and lights in the horse stall only so we installed 6 – 6″ turbine vents spaced evenly throughout the horse stalls and cracked the windows to allow air to come in. This seemed to help for a while but now I’m having the same issue with condensation. When I cut a hole in the ceiling above one of the horse stalls, it is dry about half way down and the other half I have moisture trapped in the insulation. Any ideas/ information on how to stop the condensation?”

Mike the Pole Barn Guru answers:

An average 1100 pound horse intakes 5 to 10 gallons of water a day – all coming back out in one form or another. For good equine health, air flow is essential, most usually handled by intakes from vented soffits and exhaust from ridge vents (for extended reading: https://www.hansenpolebuildings.com/2012/11/horse-barn-ventilation/). Most post frame stall barns have unfinished interiors, further allowing for air flow. In your case, you have sealed off air infiltration points and are seeing negative results from 40 to 80 gallons of water vapor (333 to 667 pounds) being added to your barn’s air daily. This does not take into account moisture rising from any floor areas without concrete slabs on grade (or slabs without a well-sealed vapor barrier below).

Riding Arena Interior
Air’s ability to hold moisture is a function of temperature. Your building has roughly 22,800 cubic feet of volume. At 40 degrees F and a 90% relative humidity (RH) you would have 33 grains of water vapor per pound of dry air (13.33 cubic feet). With 7000 grains per pound of water you get:

333# x 7000 grains = 2.331 million grains.

22,800 cft / 13.33 cft = 1710# of air x 33 grains = 56,444 grains.

Just to maintain even a 90% RH at 40 degrees F you would need to turn the air in your barn 41 to 83 times per day (depending upon actual output). To get to 60% RH (high end of comfortable living) air turns would need to double, for 30% RH triple.

Your solution is going to be to mechanically ventilate your barn. An HVAC professional can design a system for you to remove your excess moisture – otherwise you are looking at problems beyond just condensation (mold, mildew and premature degradation of lumber), such as your horses’ health.

This entry was posted in Pole Barn Questions, Pole Barn Design, Ventilation, Building Interior and tagged horse barn ventilation, mechanically ventilate, post frame stall barns, relative humidity, condensation, soffits, HVAC, horse barn condensation, equine health on April 9, 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 Roofing Materials, Pole Barn Planning, Post Frame Home, Ventilation, Concrete, Insulation, Pole Barn Homes, Pole Barn Questions and tagged add on, vapor barrier, A1V reflective radiant barrier, condensation, A1V, mother-in-law apartment, roof condensation, drip stop on March 22, 2021 by admin.

Gable Fan, Clay Soils, and Condensation Issues

This week the Pole Barn Guru answers reader questions about use of a gable fan to prevent condensation, building with posts in clay soils, and addressing condensation issues in a three-stall garage.

DEAR POLE BARN GURU: I have been reading some post on your site about gable vents. I have a 40×80 building with spray foam on the bottom of the roof, which is sheeted with plywood. The walls have rigid foam and fiberglass. Question is, would an electric gable fan help or hurt condensation in the building, and is it even necessary. Much of the building will become heated and cooled living space. STEVE in SOMERSET

DEAR STEVE: It is very possible a humidity controlled electric fan would assist in reducing condensation, however before moving forward with it, I would recommend you consult with your HVAC provider, as a properly designed heating and cooling system can be set up to provide adequate air exchanges and control humidity.

DEAR POLE BARN GURU: I have heavy clay soil that does not drain. If I put posts in ground the bottom 2 feet will be soaked most of the year. Should I use concrete piers or will proper treated post be ok? MATT in MORRISTOWN

DEAR MATT: Having personally built a post frame combination garage/shop/mother-in-law apartment at our son Jake’s then home near Maryville, I feel your pain when it comes to Tennessee clay soil. Properly pressure preservative treated columns are not negatively affected by ground water, however you have other factors to consider before moving ahead with your build. You’ll want to read these articles discussing them: https://www.hansenpolebuildings.com/2019/06/post-frame-construction-on-clay-soils/ and https://www.hansenpolebuildings.com/2020/07/barndominium-on-expansive-soils/.

DEAR POLE BARN GURU: Hello, We are building a 3 garage pole barn and would like to know if you suggest the following:
A. Can you spray foam insulation to house wrap and do you leave the paper under mullions if removing the paper?
B. We have sweating on our house wrap and in our bay that will be mostly finished we put insulation boards which had paper on both sides and now will have to remove that side siding to remove it.
C. Our bay 3 floor is just stone, the others are concrete. We didn’t put a vapor barrier plastic under stone, so until spring when we remove stone and do this we were thinking of laying a tarp tight on stone to hold back any moisture into the rooms for humidity and condensation. What do you suggest? LAURIE in NEW YOUR

DEAR LAURIE: While there are some installers who will spray foam to a WRB (Weather Resistant Barrier aka house wrap), we do not recommend it https://www.hansenpolebuildings.com/2020/04/spray-foam-insulation-3/

If you are getting condensation inside of your WRB it is due to excess moisture in your building. You need to eliminate or minimize sources of water vapor (seal any concrete slabs-on-grade if a well-sealed vapor barrier was not installed beneath). Proper ventilation from eave to ridge will also help to alleviate this challenge.

Provided you can well-seal a tarp, it is certainly a better option than just leaving raw stone exposed.

This entry was posted in Columns, Insulation, Pole Barn Questions, Pole Barn Design, Pole Barn Heating, Pole Barn Planning, Ventilation, Building Interior and tagged gable vents, ridge vent, moisture barrier, UC-4B, condensation, gable vent fan, treated posts, clay soils, wet soils, Ventilation on February 22, 2021 by admin.

Fun With a Cheap Steel Truss Pole Building

Most of our country is unfamiliar with low budget steel truss pole barns produced and sold primarily in Southeastern states. There is a reason these are prevalent where there is no snow – just in case you were wondering.

Disclaimer, I have no issues at all with prefabricated light gauge steel trusses, provided they have been manufactured to engineer sealed drawings, specific to loading conditions where they will be put into use. AND if they are fabricated by a certified welder (rarely occurs).

Reader KEVIN in COLUMBIA writes:

“Hi Guru,

I recently purchased a home and the property included a 32×84 Pole barn. The barn was never dried in and was barely completed by the previous owner. However, everything is solid, square and plum; with the exception of a few pieces of steel on the roof that were never installed, it is a solid structure. Immediately after purchasing the home I had a monolithic slab poured under half of the structure that will become the foundation for the home of my new shop. I am quite comfortable with carpentry, but not so much with insulation. How do I go about condensation proofing the roof? I really do not want to pull the existing roof panels off to lay a vapor barrier over the purlins. My intention is to have a well ventilated attic, insulate the walls, and blow in insulation over the ceiling. I have heard of some people installing foam board to the exposed steel. Spray foam is an option, but one that is out of my price range for the moment. I have attached some images for your inspection. The 3D CAD models should provide a better illustration of what is under the roof. I look forward to your response.”

Kevin is now experiencing joys associated with buildings sold ‘on the cheap’ – with barely enough materials to get a roof on with a minimal budget. It would have been so simple for this building to have been originally sold and erected with provisions to control roof condensation. Either a Reflective Radiant Barrier (RRB) or an Integral Condensation Control (ICC) would have easily avoided your current situation.

This style of building does not lend itself well to installation of a ceiling (there are no clips along truss bottom chords to accept ceiling joists). My educated guess is these trusses are not designed to support weight of a ceiling. With 2×6 purlins spanning 12 feet, they are sadly not stiff enough to keep drywall joints from cracking – so you are going to be faced with lots of limitations.

Foam board might be a solution, however you would need to have each panel 100% air sealed between purlins in order to do so. Chances of success range close to zero. You are left with two choices – remove roof steel, install a RRB and reinstall roofing or two inches of closed cell spray foam (roughly $5700). Hopefully you have poured your slab on grade over a well-sealed vapor barrier, if not – use a sealant on top of it (not as effective, but better than nothing).

This entry was posted in Trusses, Ventilation, Insulation, Budget, Pole Barn Questions, Pole Building Comparisons, Pole Building How To Guides and tagged condensation, monolithic concrete slab, blow in insulation, attic, foam board, steel truss, reflective radiant barrier, steel truss pole barn, insulation, monolithic slab on December 18, 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 Ventilation, Building Interior, Insulation, Pole Barn Design, About The Pole Barn Guru, Pole Barn Planning, Pole Barn Structure and tagged condensation, CDX plywood, nanogram, vapor control, insulation, vapor barrier on December 15, 2020 by admin.

Vapor Barrier for a Ceiling

Reader GEORGE in LOUISVILLE writes:

“I am looking to install tin on the ceiling of my 54 X 75 pole shed. I was wondering if 6 mil plastic sheeting with all seams taped would work for a vapor barrier? My concern is not to have it rain in my building after the tin is up and the heat is on.”

Mike the Pole Barn Guru:

Well George, this answer is not going to be nearly as simple as your question.

Prevention of internal rain (condensation) is going to be a function of several aspects.

#1 Controlling source – if there is not a well-sealed vapor barrier under your concrete slab on grade, you should be planning on two coats of a good sealant for it. If you do not know if there is a vapor barrier under it or not, leave a wrench on it overnight. Next day, pick the wrench up and if there is a dark place on the floor surface where the wrench was, you have no under slab vapor barrier.

#2 Source of heat – some heat sources add significant amounts of water vapor into your internal air (propane being a prime offender). Know what you are getting into before it becomes a challenge you do not want.

#3 How are you currently controlling condensation? If your building has a thermal break between purlins and steel roof – excellent. If not, your best solution is going to be two inches of closed cell spray foam applied to the underside of roof steel. This is not an inexpensive solution, but it is more practical than removing roofing, adding a thermal break, and reapplying roofing (plus roofing never goes back on as well as it was originally installed). Plan on $4000 to $4500 for closed cell spray foam.

#4 Ventilation – you are going to create a dead attic space above an insulated ceiling. If it is not adequately vented you are going to have problems. Best combination is vented eaves and ridge. Your building will require at least 1944 square inches of net free ventilation area (NFVA), distributed equally between eave and ridge. If this is not possible (building has no sidewall overhangs), then your choice is limited to gable vents and it will take many of them to provide adequate NFVA.

#5 You are in Climate Zone 5. This means a Class I or II vapor retarder is required for the interior side of framed walls. This could be 6 mil polyethylene (Visqueen) or Kraft-faced fiberglass batt insulation. For your ceiling a plastic vapor barrier should only be installed in vented attics in climates with more than 8,000 heating degree days. In Nebraska, heating degree days for a normal year is 6322.

This entry was posted in Roofing Materials, Pole Building How To Guides, Steel Roofing & Siding, Ventilation, Concrete, Pole Barn Questions and tagged propane heat, roof condensation barrier, vented eaves, condensation, Ventilation, visqueen, thermal break, visqueen vapor barrier, vented ridge on November 18, 2020 by admin.

Bolt to Slab, Metal Distortion, and a Moisture Drip Issue

This week the Pole Barn Guru answers questions about use of dry-set brackets to existing slab, spray foam distorting metal, and a problem with drip when temperature is just right.

DEAR POLE BARN GURU: How thick does the edge of concrete need to be to support a pole barn if using the bolt on top of existing slab? CHRIS

DEAR CHRIS: Our independent third party engineers have determined brackets dry mounted to existing concrete slabs are not a good structural solution and will no longer certify such connections. We would recommend either saw cutting holes in your slab to use either embedded or wet set bracket mounted columns, or to place columns around your slab’s perimeter.

DEAR POLE BARN GURU: Why does the spray foam distort the metal? LARRY in KALISPELL

DEAR LARRY: Properly installed closed cell spray foam insulation should not distort either roof or wall steel. My lovely bride and I used it when we added an elevator shaft on the rear endwall of our shouse and it was used to insulate a recent approximately 3000 square foot addition to Hansen Pole Buildings’ warehouse. Both were done with no noticeable steel deflection. Here is some further reading on this subject https://www.hansenpolebuildings.com/2020/04/spray-foam-insulation-3/.

DEAR POLE BARN GURU: We have a moisture problem in our 36×45 pole barn when the weather is right it drips when the sun warms it up. I understand I need more ventilation. Along the top center ridge there is formed foam gasketing like you have talked about. Some of it is falling out. Can I remove that to improve ventilation or is that there to stop rain or snow from coming in? Really appreciate many of the tips you have on your site. RON in MAZOMANIE

DEAR RON: I will suspect your dripping issue is due to there being no thermal break between your building’s roof framing and roof steel. If this is your circumstance, your only real solution is to have two inches of closed cell spray foam applied to inside of your roofing. While adding ventilation may remediate some of your challenge, there is still going to be some degree of warm moist air trapped inside.

In order to adequately ventilate, you will need to have both an air intake and an exhaust. You could remove your ridge cap and replace your present formed ridge closures with a similar vented material (vented closures). For air intakes, if your building does not have vented sidewall overhangs, you could add gable vents at each end.

This entry was posted in Ventilation, Concrete, Professional Engineer, Insulation, Pole Barn Questions, Roofing Materials and tagged dry set brackets, Existing slab, steel distortion, moisture problem, condensation, wet set brackets, spray foam on September 21, 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 Steel Roofing & Siding, Barndominium, Roofing Materials, Shouse, Pole Barn Planning and tagged condensation, barndominium, thermal break, I.C.C., reflective radiant barrier, shouse, hydrophilic, vapor barrier on September 3, 2020 by admin.

A Shouse, Eliminating Condensation, and Building Trusses

This week the Pole Barn Guru answers reader questions about the design of a shouse (shop house), a resolutions for condensation, and building trusses.

DEAR POLE BARN GURU: Hi – We are looking into pole barn buildings however we’re clueless on where to start and how big we actually need it to be. My husband has an HVAC business so we would need the garage/shop to be big enough for at least 3 bays plus a small shop and storage. 4 Bedrooms and at least 3 baths, ideally we’d like to have an open floor plan below and the bedrooms be in a loft type. What would you recommend?

Thank you! STEPHANIE in BELLE VERNON

DEAR STEPHANIE: Thank you for reaching out to me. In order for you to end up with an ideal dream solution, it will take some homework:

Plan tips – consider these factors:

Direction of access (you don’t want to have to drive around your house to get to garage doors)

‘Curb appeal’ – what will people see as they drive up?

Any views?

North-south alignment – place no or few windows on north wall, lots on south wall
Overhang on south wall to shade windows from mid-day summer sun If your AC bill is far greater than your heating bill, reverse this and omit or minimize north overhangs.

Slope of site

Work from inside out – do not try to fit what you need within a pre-ordained box just because someone said using a “standard” size might be cheaper. Differences in dimensions from “standard” are pennies per square foot, not dollars.

Use links in this article to assist with determining needed spaces, sizes and how to get expertly crafted floor plans and elevation drawings https://www.hansenpolebuildings.com/2019/10/show-me-your-barndominium-plans-please/

DEAR POLE BARN GURU: Hi, I had seen a post mentioning your Gable vents. I have a pole barn with 12″ lapped steel siding and would like to install Gable vents on the ends to help with condensation. Barn is 40×60. MIKE in MINNEAPOLIS

DEAR MIKE: If you have a steel roof with nothing on underside to create a thermal break, and are getting condensation you should have two inches of closed cell spray foam applied to it.

For a 40×60 building you would need to have eight square feet total of net free ventilation with at least half of it located in top half of your attic. This amounts to 576 square inches of net free ventilation area in each endwall. Please contact Materials@HansenPoleBuildings.com to request a price quote, provided steel ribs are no greater than 3/4″ tall (they will need this information on net free area and your zip code).

DEAR POLE BARN GURU: I have posts for a pole barn set 15 of how should I build truss for this set up? DANIEL in SNYDER

DEAR DANIEL: You should contact your nearby prefabricated wood truss manufacturer and order from them. Do not attempt to build them on your own.

This entry was posted in Pole Barn Homes, Insulation, Shouse, Pole Barn Questions, Pole Barn Design, Trusses, Ventilation, Building Interior, Professional Engineer and tagged shouse, shop house, building trusses, trusses, condensation on August 17, 2020 by admin.

A Garage Apartment, A Moisture Problem, and Insulating a Ceiling

Today’s Pole Barn Guru answers questions about building a garage apartment aka a “Shouse,” how to address a moisture problem, and the best way to add insulation to a ceiling.

DEAR POLE BARN GURU: Can I design a garage apartment pole barn? JAY in HINTSVILLE

DEAR JAY: You may not have this ability however we have experts who can assist you. To develop a workable custom floor plan, designed specifically to meet your wants, needs and budget please use this link: http://www.hansenpolebuildings.com/post-frame-floor-plans/?fbclid=IwAR2ta5IFSxrltv5eAyBVmg-JUsoPfy9hbWtP86svOTPfG1q5pGmfhA7yd5Q

DEAR POLE BARN GURU: Live in the Midwest, have a 54 x 36 pole barn well insulated, walls, and ceilings. When it rains a lot I have a moisture problem, My building is approx. 1950 Sq. Ft. I found a dehumidifier that covers 3,000 sq. ft. I was thinking about putting one in the pole barn, it can run continuous if I put a hole in the side, for a drain, and let it drain out, just leave it running on its own as it needs to. Is this Ok to do to solve my issue? RON

DEAR RON: A dehumidifier may resolve your building’s symptoms, however not its problem. As this is a function of rain, I am led to believe you need to eliminate or reduce your moisture source. If your building does not have a vapor barrier under your concrete floor, seal top of floor. If you do not have rain gutters install them and ensure runoff is directed well away from building. Make sure ground outside of building is sloped away at least 5% for 10 or more feet.

DEAR POLE BARN GURU: I have a 32X46X15 pole barn with purlins attached to the outside of the 6×6 beams. The barn has soffits and a vented ridge cap and is set up for a ceiling. I have since decided to keep the rafters exposed and have questions about sealing up the soffits and ridge cap but leaving several small openings in the ridge cap to allow for humidity to escape.

How much should I leave open on the ridge cap and should I totally seal off the soffits? Will it be ok to leave the beans and rafters exposed, putting a vapor barrier in between the beams and the rafters?

What are your thoughts on 2in foam with no vapor barrier glued directly to the metal in between the purlins every 2feet? Then another 2in foam board with a vapor barrier placed on top of that screwed to purlins and can spray foam the edges and gaps? Thanks for all your help! MARK in VALPARAISO

DEAR MARK: My response is with a thought you are trying to climate control your building to some extent. Your proposal to use two inch-thick foam insulation board sounds to be highly labor intensive as well as being fraught with challenges in trying to achieve a complete air seal. Any air gaps would allow for warm moist air from within your building to not only condense against your building’s steel cladding, but also to remain trapped there, potentially being a cause of premature degradation of steel panels.

I would recommend you look towards closed cell spray foam as a solution for both insulation as well as condensation control. You will want to completely seal both eave and ridge then have at least a two inch thick layer of closed cell foam sprayed on interior face of roofing and siding. A mechanical dehumidifier should be used to control relative humidity with your building.

This entry was posted in Shouse, Pole Barn Questions, Ventilation, Pole Barn Apartments, Shouse, Insulation and tagged garage apartment, insulation, condensation, spray foam, foam boards, moisture, shouse on May 4, 2020 by admin.

Two Story House, Car Storage, and a Post Frame Basement

Today’s Pole Barn Guru answers questions about building a two story pole barn house, condensation in a car storage building, and how to build a post frame house with a concrete basement.

DEAR POLE BARN GURU: We are wanting to build a 2 story pole barn house, it will have an upstairs loft. Would the standard pole footings support 2 stories, or would it need a concrete footing foundation, like what is used in a stick built home? NICK in FAIRBURY

DEAR NICK: As long as you construct your building from engineered plans, your engineer will have properly sized your building’s “standard pole footings” to be able to adequately distribute weight across your soil. We live in a multistory post frame (pole barn) shouse with a 44 foot overall height and it has typical embedded footings and has performed admirably.

DEAR POLE BARN GURU: I have a 20′ x 40′ closed in pole barn that I use for storing cars, it has a ridge vent & the soffits & eaves are open to the weather, how can I keep the cars from sweating? BILL in EATONTON

DEAR BILL: You will need to reduce humidity in your building.

Use a good sealant on top of your concrete slab.
Install 2x blocking snugly between purlins overhanging endwalls (directly above end trusses).
Spray 2″ of closed cell insulation on inside of all wall and roof metal (leave eaves and ridge open to provide attic intake and exhaust ventilation).
Install a tightly sealed ceiling (no air gaps to attic).

Add controlled mechanical ventilation.

DEAR POLE BARN GURU: We are potentially interested in building a pole barn home and have a few questions. Cost different from a traditional home build isn’t the major concern from us, we love the open rustic feel of a barn home. We would like to include a basement with the home. I read some previous blog posts and it seems like this is possible, however was wondering do the sidewalls of the basement need to be inset from the sides where the posts go into the ground?

If the walls are inset, is it possible to have a basement with egress windows below the pole barn home? RYAN in OSWEGO

DEAR RYAN: We can have your building engineered so columns will mount directly to top of your concrete basement walls. Makes everything far easier.

This entry was posted in Ventilation, Footings, Professional Engineer, Pole Barn Homes, Barndominium, Pole Barn Questions, Building Overhangs and tagged condensation, Ventilation, concrete brackets, pole building barndominium, two story house on March 30, 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 vapor barrier, condensation, metal building insulation, inside closures, eave strut, top girt, top purlin on March 3, 2020 by admin.

Barndominium: One Story or Two?

Barndominium: One Floor or Two?

Welcome to an ongoing debate about whether it is more cost effective to build a one story or two story barndominium. Commonly I read people advising two stories is less expensive than a single story. Reader TODD in HENNING put me to work when he wrote:

“I’m curious why “Going to multiple stories will be more expensive than building the same amount of finished square footage on a single level”? Everywhere I read it says it’s cheaper to go up than out. For example wouldn’t there be more cost with bigger footprint of concrete, in-floor heating, roof trusses, and more steel on roof? Thanks.”

Mike the Pole Barn Guru writes:

It turns out Todd has requested a building quote from Hansen Pole Buildings, so I was able to work scenarios from his requested 40 foot wide by 48 foot long scenario. I arbitrarily merely doubled his building length when looking at a single story. It may have been more cost effective to have done this exercise by going greater in width and less in length (as one gets closer to square, there is less exterior wall surface to side, insulate and drywall).

Included were colored steel roofing and siding, commercial bookshelf wall girts to create a wall insulation cavity (https://www.hansenpolebuildings.com/2011/09/commercial-girts-what-are-they/), dripstop/condenstop under roof steel to minimize or eliminate condensation (https://www.hansenpolebuildings.com/2017/03/integral-condensation-control/), ceiling loaded energy heel trusses (https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/) with ceiling joists for sheetrock, 24 inch enclosed vented overhangs, vented ridge and one entry door. In the two story version I added floor trusses and a four foot wide set of stairs.

In order to maintain eight foot finished ceiling heights, two stories requires a 21 foot eave and single story 10 foot. Engineered plans and delivery were included.

I did not include materials for a bearing wall at the floor truss center. Features listed above ran roughly $6000 more to go two floors. Also, with the two floor version, you will lose 50 square feet of usable floor on each level due to stairs.

In this particular instance best overall buy could come down to what you pay for your slab and in-floor heating. Labor to erect a single story will be less expensive (I would predict at least a $3000 difference). Some other thoughts – two story has 1/2 as much attic insulation and 45% more wall insulation. Two story (excluding interior walls) has 30% more wall to drywall. This added exterior wall surface will likely result in more windows.

Personally, I own three multiple floor post frame buildings, these are my considerations:

Accessibility roughly 10% of all Americans will spend time in wheelchairs in their lifetimes. My wife is a paraplegic and we cannot get into one of her son’s homes because it is a split entry. Two of her other sons have built ramps for her, but they also have multi-story homes and it greatly limits areas she can have access to. In our own shouse (shop/house), we added an elevator after her injury (elevators are NOT cheap).

Stairs in general – you are probably much younger than my 62 years, going up and down stairs gets to be a chore as we age.

Heating and cooling – unless each floor is on their own system, one floor is always either too cool or too warm. I put one of my own buildings on two separate heat pumps for this very reason.

In conclusion, whether one story or two, go with what best fits your wants and needs and your property. Love what you build and it will result in a happy ending.

This entry was posted in Footings, Barndominium, Insulation, Building Interior, Shouse, Pole Barn Questions, Budget, Pole Barn Design, Pole Building Comparisons, Pole Barn Homes, About The Pole Barn Guru, Pole Barn Planning, Pole Barn Apartments, Trusses, Windows, Concrete, Post Frame Home and tagged commercial bookshelf girts, dripstop, wall insulation cavity, enclosed vented overhangs, Condenstop, floor trusses, condensation, ceiling joists, vented ridge on February 21, 2020 by admin.

Ganged Wood Trusses & Closed Cell Spray Foam Post Frame Condensation Control

Ganged Wood Trusses and Closed Cell Spray Foam Post Frame Condensation Control

Ganged wood trusses are most usually two individually fabricated metal connector plated roof trusses, fastened together with either nails or even better Simpson Drive Screws (https://www.hansenpolebuildings.com/2017/03/simpson-drive-screws/), so they work together as a conjoined pair.

True doubled trusses (not two single trusses spaced apart by blocking) afford many structural advantages (https://www.hansenpolebuildings.com/2018/09/true-double-trusses/). However if closed cell spray foam is being used to control condensation underneath steel roofing, a little extra prevention is worth a pound (or two) of cure.

Most often conditioned post frame buildings are designed around having a flat (or slightly sloped using scissor trusses) ceiling. Warm moist air from this conditioned space rises into building’s attic and hopefully has a place to go. Most generally best design solution involves venting this dead attic space. Appropriate amounts of air intake provided by eave soffit vents and air exhaust utilizing a vented ridge will eliminate most moisture.

As those of us who did not nap during science classes are aware – warm air rises. Some of this warm air will get trapped below roof purlins or other attic framing members and not exhaust as imagined.

There are many methods of controlling or eliminating this warm and moist air from coming into contact with cooler roof steel. Least expensive (although potentially labor intensive if windy) would be a reflective radiant barrier (https://www.hansenpolebuildings.com/2017/05/effective-reflective-insulation/). One step up in investment, but very easily installed, would be an Integral Condensation Control (https://www.hansenpolebuildings.com/2017/03/integral-condensation-control/).

Some folks opt to sheath over trusses and roof purlins with OSB (Oriented Strand Board) or plywood, with 30# asphalt impregnated paper (roofing felt) placed between sheathing and roof steel. This can tend to run up one’s investment, as not only will more material and labor be directly involved, but trusses also must be appropriately designed for added weight carrying ability.

Enter closed cell spray foam. Long time readers have grown tired of me solving condensation challenges by people who did participate in one of these solutions and are now faced with a drip-drip-drip. Two inches of closed cell spray foam applied beneath a steel roof between purlins and trusses will create an almost entirely effective thermal break and take care of nearly all condensation issues.

Except…..
Metal connector plates trusses have pressed steel plates on each side. These plates project slightly from lumber faces and when two trusses are joined together, some gaps will occur between them. Gaps wide enough to allow for a significant flow of warm moist air to reach your roof steel, condense and start wreaking havoc.

There is, however, a simple fix, easily done during building framing. Before conjoining two or more trusses, place enough urethane or acoustic caulking between top cords to provide a complete air seal when in service!

This entry was posted in Ventilation, Building Interior, Pole Barn Homes, Insulation, Post Frame Home, Roofing Materials, Pole Barn Planning, Pole Barn Structure, Barndominium and tagged roofing felt, reflective radiant barrier, ganged wood trusses, closed cell spray foam, closed cell spray foam insulation, reflective insulation, plywood, condensation on January 21, 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 Pole Building How To Guides, Pole Barn Homes, Pole Barn Planning, Pole Barn Structure, Barndominium, Insulation, Ventilation, Pole Barn Questions, Building Interior, Pole Barn Design and tagged bookshelf wall girts, vented ridge, insulation, vapor barrier, barndominium condensation, condensation, BIBS insulation, batt insulation, gable vents on December 4, 2019 by admin.

Post Frame Building Insulation

Pole Barn Guru’s Ultimate Guide to Post Frame Building Insulation

When it comes to insulating any building (not just post frame ones – like barndominiums) there is a certain point of diminishing returns – one can spend so much they will never, in their lifetimes, recoup their investment.

Here my ultimate guide to post frame building insulation is based upon practicality and obtaining the best possible value for investment.

There are some basics applicable to any steel covered building:

Under any concrete slab on grade inside a building, place a well-sealed vapor barrier. Read about under slab vapor barriers here: https://www.hansenpolebuildings.com/2017/11/vapor-barriers-slabs-grades/.

Between roof framing and steel roofing – please do not assume condensation is not going to be a problem. At some point in time it will become one and if precautions are not taken regrets will happen. Condensation under roof steel is maybe number one of the issues I am asked to assist with.

Least expensive financially, but does take some extra labor hours, especially if it is windy – a single air cell layer reflective radiant barrier. Six foot widths will install much quicker than four foot. Make sure to order with a six foot width NET COVERAGE and an adhesive tab along one edge with a pull strip. Without an adhesive tab all butt edges will require seam tape, not expensive, but adds lots of time. Do not waste your money on adding an extra approximate R 0.5 for double bubble (two layers of air cells).

For a slightly great investment in materials, hours of labor can be saved by the use of an Integral Condensation Control bonded to roof steel. This would be my product choice. https://www.hansenpolebuildings.com/2017/03/integral-condensation-control/.

Next higher cost would be sheathing the roof with either OSB (Oriented Strand Board) or plywood on top of roof purlins. Roof purlins will need to be spaced appropriately so sheathing seams fall on purlins (16, 19-3/8 or 24 inches on center). Roof truss top chord live load must be increased to allow for greater dead loads. Either 30# felt (asphalt impregnated paper) or an Ice and Water Shield must be placed between sheathing and roof steel. Roof screws must still be placed to go into purlins, as thin sheathing is inadequate to adequately hold screws.

Bigger financial investment, but no extra labor involved is to have two inches of closed cell foam sprayed on the underside of roof steel. This will prevent condensation and is noise deadening. As a rough budgetary figure, plan upon spending roughly two dollars per square foot of roof surface.

Storage/Utility Buildings

If you ever believe anyone might ever have a future desire to climate control your building then provisions should be made for making it easiest to make future upgrades.

For now we will assume this building is totally cold storage. If it might ever (even in your wildest dreams) be heated and/or cooled include in your initial design, walls with a Weather Resistant Barrier (https://www.hansenpolebuildings.com/2016/01/determining-the-most-effective-building-weather-resistant-barrier-part-1/) between framing and siding.

Taking walls one step further would be ‘commercial’ bookshelf wall girts (https://www.hansenpolebuildings.com/2011/09/commercial-girts-what-are-they/).

In roof – have trusses designed to support a ceiling load, ideally of 10 pounds per square foot (read about ceiling loaded trusses here: https://www.hansenpolebuildings.com/2016/03/ceiling-loaded-trusses/).

Trusses should also be designed with raised heels to provide full depth of future attic insulation above walls (https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/).

Make provision for attic ventilation, by having an air intake along sidewalls using enclosed ventilated soffits and exhaust with a vented ridge.

Any overhead doors should be ordered insulated – just a good choice in general as, besides offering a minimal thermal resistance, they are stiffer against the wind.

Equine Only Use

Same as storage/utility however ventilation is essential (and often overlooked). (Read more on stall barns here: https://www.hansenpolebuildings.com/2012/08/stall-barn/)

Garage/Workshop/Man Cave/She Shed/House/Shouse/Barndominium

Many previous recommendations are going to be repeated here. Ultimately it is going to depend upon willingness to include higher R values in initial budget, rather than having increased utility bills forever.

Start with a Frost-Protected Shallow Foundation – post frame version (https://www.hansenpolebuildings.com/2016/11/frost-protected-shallow-foundations/) with sand on the inside rather than a thickened slab. This makes for an excellent and affordable design solution.

For walls, we will again work from generally ascending price and R values.

On low end would be having installed a weather resistant barrier beneath wall steel, in conjunction with commercial bookshelf wall girts. Fill insulation cavity with unfaced batt insulation and cover inside face of wall with a well-sealed six ml clear visqueen vapor barrier. As an alternative to fiberglass would be mineral wool insulation as it is not affected by moisture (https://www.hansenpolebuildings.com/2013/03/roxul-insulation/). This method can be entirely done D-I-Y.

I have personally used BIBs (https://www.hansenpolebuildings.com/2011/11/bibs/) in several buildings, including my current barndominium home. It does require a certified installer.

A Weather Resistant Barrier can be eliminated by the use of a ‘flash coat’ of two inches of closed cell spray foam against the inside of wall steel. Balance of wall cavity can be filled with batt insulation. (https://www.hansenpolebuildings.com/2016/07/advantages-spray-foam-over-batt-insulation/).

For added R value and a complete thermal break, add two inch rigid closed cell foam boards to inside of framing. To maintain thermal break integrity, glue foam boards to inside of framing and properly seal all seams. Gypsum wallboard can be glued to the face of foam boards.

After ceiling has been installed, have insulation blown into dead attic space, following Energy Star™ guidelines (usually R-45 to R-60).

This entry was posted in Ventilation, Insulation, Post Frame Home, Pole Barn Design, Barndominium, About The Pole Barn Guru, Roofing Materials, Pole Building How To Guides, Pole Barn Planning and tagged integral condensation control, reflective radiant barrier, ice and water shield, commercial bookshelf wall girts, insulation, condensation on November 27, 2019 by admin.

My Barndominium Windows Are Leaking

Common questions we hear from barndominium, shouse (shop/house) and post frame home owners are, “Why are my new windows leaking?” or “Why do I have condensation inside of my windows?” In fact, many new barndominium owners think their windows are defective and need to be replaced in an effort to cure this problem. To answer these questions, let’s review what causes window condensation.

Condensation is visible evidence of excess air moisture. It may appear as water, frost, or ice on window or door surfaces. This occurs more frequently during winter months because of extreme differences between inside and outside air temperatures. Warmer air holds more water meaning air in any given room center will hold more water than air adjacent to window or exterior door walls, since this area is always cooler. When warm, moisture laden air moves toward cooler window or door walls, it becomes cooler and cannot hold as much moisture as it held when it was warmer. This moisture is dropped and appears as water on glass and frames of windows and doors.
Windows do not cause condensation, they just happen to be where moisture is most visible. Condensation is a sign of excess moisture in barndominiums. This can be caused by temporary conditions such as:
Building materials contain a great deal of moisture. As soon as heat is turned on, this moisture will flow out into the air and settle on door and window glass. This will usually disappear following first heating season. During humid summers, houses absorb moisture. This will be apparent during the first few weeks of heating and then should dry out. Sharp, quick, and sudden drops in temperature especially during the heating season will create temporary condensation problems.

Condensation can also be caused by more permanent conditions:
Insufficient attic ventilation and/or soffit ventilation traps moisture in barndominiums. Having sufficient soffit vents to allow adequate air flow in and ridge vents for exhaust will allow moisture and humidity to escape. Excessive humidity may be a result of poor ventilation but can also be a result of an imbalanced heating and air system or a need to add additional ventilation. Inadequate (or missing) vapor barriers under concrete slabs on grade. While Building Codes require a vapor barrier under any concrete slabs in heated buildings, it is all too often overlooked.

Controlled ventilation and elimination of excessive indoor moisture can keep humidity within bounds. Here are some suggestions to help reduce indoor moisture:
Turn off or set back furnace humidifiers until sweating (condensation) stops. Remove pots of water on radiators or kerosene heaters. Use exhaust fans or open windows slightly in kitchen, bathroom and laundry room during periods of high moisture production such as cooking, taking showers, washing and drying clothes. Clothes dryers must be vented outside. Do not hang clothes to dry indoors. Waterproof concrete floors. Make sure attic vents are unobstructed. Place all house plants in one sunny room where the door can be kept shut and avoid over watering. Opening windows slightly for a brief period of time will allow humid air to escape and drier air to enter. Use a properly sized dehumidifier, to reduce humidity.
Excessive indoor humidity and moisture are not a result of your windows. You should view the amount and severity of window condensation as a clue moisture damage may be taking place inside walls or ceiling cavities of your barndominium. This can lead to rotting wood, deteriorating insulation, and blistering paint.

This entry was posted in Pole Barn Design, Pole Building How To Guides, Pole Barn Planning, Pole Barn Structure, Windows, Pole Barn Homes, Post Frame Home, Pole Barn Questions, Barndominium and tagged barndominium condensation, barndominium ventilation, dehumidifier, condensation, Ventilation, attic vents on November 19, 2019 by admin.

Roof Trusses 4′ o.c., Condensation Issues, and a Sliding Door

This Monday the Pole Barn Guru answers questions about roof trusses at 4′ o.c., ways to solve condensation issues, and sliding door options.

DEAR POLE BARN GURU: My question is I just purchased some roof trusses that are 32 feet long heel to heel they are constructed with 2 by 4s can I put these on 4 foot centers? Thanks. CRAIG in BELVIDERE

DEAR CRAIG: You can if you want your building to collapse in a moderate snow event. Along with your trusses, you should have received an engineer sealed truss drawing with all specifics as to what can be carried by it and spacing. If you did not, and they are prefabricated metal connector plated wood trusses, there should be a manufacturer’s stamp somewhere on truss bottom chords. You could then contact them and give them truss specifics (and probably a few photos showing lumber grades, web configuration and steel connector plate sizes. From this, they may be able to determine what you have actually spent your hard earned money on.

If you are unable to determine where they came from, another alternative would be to take their information to a Registered Professional Engineer with roof truss experience. For a few hundred dollars, you may be able to get an opinion as to their strength.

DEAR POLE BARN GURU: Hello, I have a 30x46x16 all steel pole barn that I am having condensation problems with. My question is what is the best thing I can install or do to help the problem? I have been told by others to install a ventilation exhaust fan controlled by an thermostat. I do have electricity in barn. I also have a wind turbine I haven’t installed yet too? Should I put both of these items in or one of them? And if so, do you guys install these items? Please help, its rusting all my tools and growing mildew in my RV!! Thanks ALYSSA in LEWIS CENTER

DEAR ALYSSA: You have found a challenge (one of many actually) Quonset steel building providers never seem to mention – condensation (read about other Quonset issues here: https://www.hansenpolebuildings.com/2011/07/quonset-huts/).

The two best things you can do are to seal your concrete floor (https://www.hansenpolebuildings.com/2019/02/how-to-properly-apply-post-frame-concrete-sealant/) and have two or more inches of closed cell spray foam insulation applied to the inside of your steel building shell. An exhaust fan might help, provided it can adequately move enough air (need to move between 3000 and 4000 CFM – cubic feet per minute) and it will require an air inlet of similar dimensions. We are not contractors, so we won’t be able to assist you with any installations.

Figure 27-5

DEAR POLE BARN GURU: Hi. Not really looking for a whole building. What I am looking for is an exterior sliding door to install onto a shop wall. The Shop is a timber frame unit. The opening is roughly 6 feet wide by 7 – 7.5 feet tall. I have not yet taken exact measurements. I will as soon as I can find a vendor within my price range.

I was very intrigued by your video presentation describing the “nail on” round track system. Also, this shop is in an odd location. It is a basement shop under my house, the house is built on a slope, so the wall I want to put the door onto is at ground level, but the opposite wall is fully underground. Since it is an exterior door to my basement any info on weather sealing for the cold Vt. Winters would be greatly appreciated. ANDREW in WESTMINSTER

DEAR ANDREW: Whilst I can appreciate you thinking a sliding “barn style” door might be a solution, I am doubtful as to it truly being a viable design solution. At best a sliding door will be a challenge to insulate beyond a bare minimal R value. A bigger concern is you are not going to achieve a tight air seal.

A design solution I can recommend (although it may stretch your budget) would be to go with an insulated commercial steel double entry door (six feet wide) in steel jambs. These doors will afford a secure access to your shop, are insulated and can seal air tight.

Although we typically only provide doors with our complete third-party engineered post frame building kit packages, you can message Materials@HansenPoleBuildings.com for a delivered price.

This entry was posted in Trusses, Ventilation, Concrete, Sliding Doors, Pole Barn Questions and tagged condensation, spray foam, sliding doors, truss loads, seal floor, roof trusses on October 14, 2019 by admin.

Exhaust Fan to Reduce Pole Barn Condensation Issues

Post frame (pole barn) building condensation problems are a re-occurring theme. With proper design and planning, condensation should not occur, however more often than not this is a penny wise, pound foolish event – caused by post frame building providers (either builders or vendors) not advising new building owners of possible challenges.

Reader JEFF in MICHIGAN writes:

“Hi Mr. Guru. I have a 1 year old, 2400 sq.ft. pole barn at my northern MI home. The barn is a wood frame, well insulated, drywalled, and Hardi board exterior barn with asphalt shingles. I’m not sure of a vapor barrier under the concrete floor, it was poured before I saw it.

I have 2ea. 56k BTU “standing pilot”, ventless heaters (no electricity required) to keep the inside temp above freezing (45-50*) in the winter for boat storage and occasional projects. I went powerless because this is more of a summer home at this point and I’m not up there much in the winter. If there’s a power outage, my barn will stay warm.

That being said, I have a condensation problem. I’m thinking a louvered, 24″ exhaust fan running through a humidistat switch and an intake grill on opposite ends of the barn should cure the issue. I’m looking for verification that this will fix my problem before I buy the fan and cut holes in the walls or if maybe you have another, simple solution.

Thanks for your help.”

Mike the Pole Barn Guru writes:

For those unfamiliar with “standing pilot”:

A standing pilot is a standard ignition device for most natural gas burning heating systems, and has been for many years. It’s a continuously burning flame at heater bottom, responsible for starting burners actually generating heat for a post frame building. Though it’s a widely used technology, there are a few things giving it a less-than-stellar reputation.

Standing pilot lights are actually fairly simple in design. A gas line terminates in a small burner, where the flame is created. A bit of composite metal wire, called a “thermocouple,” connects the burner to a gas line valve. When the pilot light is lit, thermocouple registers heat and generates an electric current. This current travels down thermocouple to the gas valve and opens it. This is what keeps the pilot light burning. When the pilot light goes out, thermocouple’s electric current stops and gas valve closes. This is a safety measure to prevent gas from flooding your home.

Most common problem for standing pilot lights is the light going out. This tends to happen because the flame is unprotected from air currents or sudden draft. Though there is an ignition system on most heaters to relight the pilot light, other issues can occur.

Thermocouple for pilot light often wears out over time, eventually losing the ability to create an electrical current. This can occur from wear and tear, corrosion, becoming detached from volt meter, or simply becoming bent way from pilot flame. Regardless of how thermocouple stops working, the pilot light is unable to stay lit. If your pilot light seems to light without issues, but almost immediately goes out, it’s because thermocouple is no longer keeping gas valve to flame open.

Jeff’s starting point should be to eliminate, or at least minimize where moisture is coming from. Place a wrench on your floor overnight, if a dark impression remains on floor (sort of like chalk body outlines at murder scenes) when removed you know you have no vapor barrier underneath your slab. Seal your floor.

Next culprit is your heaters. You’ll want to read more here: https://www.hansenpolebuildings.com/2019/02/how-to-reduce-condensation-in-post-frame-buildings/.

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 40 x 60 x 14 = 33,600 cubic feet X 10 times / 60 minutes per hour = 5600 cfm.

I hope this helps, and good luck!

This entry was posted in Pole Barn Questions, Ventilation, Pole Barn Heating and tagged condensation, pole barn condensation, thermocouple, standing pilot, heating systems, pilot light on August 30, 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 Planning, Pole Barn Structure, Ventilation, Uncategorized, Insulation, Pole Barn Questions, Pole Barn Design, About The Pole Barn Guru 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.

Unvented Post Frame Attics

Energy efficiency concerns have literally become a “hot” (pun intended) topic in new construction, and post frame construction methods are no exception to inclusion. Traditionally buildings have had insulation placed or blown into dead attic spaces, directly above a ceiling. Unvented attics have entered fray as an alternative.

To construct an unvented attic, air-impermeable insulation (think closed cell spray foam) will be applied in direct contact with steel roofing (or sheathing) underside and gable end walls so as to tie roof insulation into wall insulation below. Moving insulation boundary to the roof deck underside allows temperature and humidity conditions in the attic to be reasonably close to those of the conditioned building interior. No attic floor vapor retarder or insulation should be installed with an unvented attic assembly.

Closed cell spray foam insulation products meet code requirements for use of an air-impermeable barrier applied to underside of roof. This prevents air infiltration and limits accumulation of airborne moisture in the attic. Using closed cell spray foam insulation applied to underside of roof deck eliminates a need for alternative methods of condensation control such as reflective radiant barriers or CondenStop (https://www.hansenpolebuildings.com/2014/07/condenstop/).

In hurricane or wildfire prone areas wind-driven rain or embers cannot enter an unvented attic assembly, as there are no vents.

Spray Foam

Vented attic designs originated in cold climate areas. In these cold climates, attic ventilation is commonly used to remove warm, humid air from attic spaces. Air leakage from conditioned spaces below a ceiling greatly increased likelihood of moist air entering attics. Without adequate attic ventilation, the underside of the roof deck can have condensation form and interior heat can cause roof surface snowmelt leading to ice damming.

Use of venting to control moisture in cold climate attics comes with some inherent challenges. In high snowfall areas, snow accumulation and drifting can often block ridge vents. This limits venting and increases potential of damage due to ice damming, roof leaks and condensation.

Closed cell spray foam does not come without added upfront investment costs, however some of these can be mitigated in materials and/or labor savings.

Considering climate control of your new post frame building? If so, an unvented attic may be a viable solution worth investigating.

This entry was posted in Ventilation, Pole Barn Design, Roofing Materials, Pole Barn Planning, Pole Barn Structure and tagged attic ventilation, closed cell spray foam, ice damming, attic ice damming, condensation on February 8, 2019 by admin.

A Case for Minimum Post Frame Truss Loads

Portions of this article were written specifically for Component Advertiser, a monthly truss industry publication. However I feel strongly enough about this subject to use my column to pitch it to both my employers and other post frame building kit suppliers and contractors.

In my career I have done about everything imaginable when it comes to post frame (pole) building trusses. I have been blessed to have been able to spend a better portion of over two decades working within or owning prefabricated MPCWT (metal plate connected wood trusses) manufacturing facilities. I have designed, engineered, fabricated and delivered trusses. As a builder, I raised my first set of post frame trusses nearly 40 years ago and many more have followed.

I have also been a provider of post frame building kit packages across most of my adult life. Our industry (post frame buildings) is one where low price, rather than service and quality, drives most sellers and buyers. Sellers, more often than not, have not learned well how to convey value of benefits they offer – instead they live in fear of being a five-spot more than their competitors when it comes to price.

For nearly seven years I have been writing a weekly advice column, “Ask the Pole Barn Guru™”, where I answer post frame building oriented questions from anyone. One repeatedly asked question is in regards to adding ceilings to existing post frame buildings. Most roof trusses for these buildings were not designed to support ceiling loads, generally due to a fear of increasing building price.

Many post frame buildings are constructed in areas where pole buildings are exempt from building permits, or there are little or no structural plans reviews done. This contributes to an attitude of “make it cheap” by encouraging use of minimal loads for trusses.

A great majority of post frame buildings are used as residential accessory buildings – garages, shops, RV parking, man caves, she sheds, etc. Nearly all of these buildings have truss spans of 40 feet or less, so my proposal for voluntary minimum loading requirements for post frame buildings will be directed towards these structures.

Why not apply these minimums to larger span structures? Many wider span buildings are going to be used as horse riding arenas or equipment storage for farming and are never going to have ceilings in them. Costs to design for greater loads, for spans of 50 feet and greater could result in some significant costs. Wide span buildings being used for more humanly occupied (and therefore more critical in protection of human life) purposes are likely to have a Registered Design Professional (architect or engineer) involved, who will specify roof loads based upon building use and function.

In areas of minimal or no snow, with Pg (ground snow load) values of under 20 psf (pounds per square foot) Top Chord Live Load (TCLL) should be fixed using a minimum of 20. For areas where white stuff has a greater possibility of occurrence 25 psf appears to be a reasonable minimum.

Most post frame buildings have light gauge steel roofing over purlins. Hopefully they also have some sort of minimal weight material between these to minimize or prevent condensation issues. In most instances, total dead loads required in order to support truss weight, condensation control, purlins and roofing will be less than 2.5 psf. There are folks who have ideas not always shared with truss designers – like using OSB or plywood sheathing between purlins and roofing. Also, rooftop solar panels are becoming more and more popular and find their way onto more than a few roofs not designed to support their weight.

My proposal (again for buildings of 40 foot spans and less) would be for a minimum TCDL (Top Chord Dead Load) of five psf. While this does not solve every possible case, it does allow for greater end user flexibility.

Traditionally, most post frame buildings did not have ceilings installed, so a very minimal BCDL (Bottom Chord Dead Load) has been used. Most typically a one psf loading will be selected, more than covering bottom chord lateral bracing and limited lighting. However, as post frame have moved from farms to suburbia, more buildings are getting interior finishes – meaning ceilings. I like to use 10 psf, in cases where I am designing for a drywall covered ceiling with insulation above, however even five psf would handle most ceiling loads.

Load duration – no snow, I am good with 1.25, snow areas 1.15. However, in my humble opinion, if TCLL exceeds 50 psf, chances are snow will be piled on top of these trusses for more than two months across structure’s lifetime and a DOL (Duration of Load) of 1.0 will be most appropriate.

A hidden side benefit to establishing these voluntary minimums will be stronger trusses able to withstand more abuse in handling. Some lumber members will be larger dimension or higher grade material and steel connector plates will increase in size. All of these factors increase probabilities of reduced truss damage.

Now, I believe, time has come to stop selling price to post frame building clients and sell benefits. Safety becomes easiest to sell – no one wants to live with a fear of their building collapsing and injuring them, their loved ones, or destroying their valued possessions. Flexibility in future use – also an easy sell, if a future building owner decides they want to add a ceiling they can safely do so.

Minimum post frame truss loading benefits all, by raising the overall quality of finished buildings with a negligible investment.

This entry was posted in Pole Barn Design, Building Department, Pole Barn Planning, Pole Barn Structure, Trusses and tagged metal plate connected wood trusses, Component Advertiser, minimum loading requirements, post frame condensation, top chord live load, top chord dead load, condensation on February 7, 2019 by admin.

How to Properly Apply Post Frame Concrete Sealant

How to Properly Apply Post Frame Building Concrete Sealant

Condensation in post frame buildings can be problematic. In order to reduce condensation probabilities, minimizing water vapor sources proves to be paramount. Concrete slabs, especially if no vapor barrier was placed beneath them, are a prime source of water vapor. Proper application of sealant can greatly reduce or eliminate water vapor transmission from slab into the building.

Concrete sealant will make your concrete more resistant to weather exposure, water, grease and oil stains, abrasion and deicing salts. What’s more, they will help to make it easier to clean. But in order for a sealer to work its magic, it must be applied properly. Each step, from surface preparation to choosing right application method for product, will have a big impact on final outcome.

Following are some tips for applying concrete sealer properly. Whichever brand of sealant you use, be sure to follow specific instructions recommended by product manufacturer, since they may differ from general guidelines given here.

When you apply sealer can be important as well. Allow new concrete to cure completely (28 days or more, as recommended). Most sealers must be applied under dry conditions, since applying sealant to damp concrete could cause haziness or loss of adhesion. Air temperatures are also important and should typically be above 50°F during and for 24 hours or more after sealer application. Always allow sealer to dry completely before exposing it to foot or vehicle traffic. Drying times before exposure to heavy traffic can be as long as three days.

Surface preparation before applying a sealant will be extremely important. All oil, grease, stains, dirt, and dust must be removed or they may prevent sealer from adhering properly. Some manufacturers recommend etching surface first with an etching solution to ensure best adhesion.

Two most common methods of applying sealant to concrete surfaces are by roller or sprayer, often depending upon whether choosing a solvent or water based sealer. Always refer to manufacturer’s specific application guidelines.

Regardless of application method always strive for maximum coverage. Typical coverage rate should be 250 to 300 square feet per gallon, depending upon concrete porosity. Most important rule to remember – it’s best to apply two thin coats, making sure sealant doesn’t puddle or form uneven, thick areas. When applying a second coat of sealant, apply it in opposite direction (or perpendicular) to first coat to ensure even coverage. Wait to apply second coat of sealant for 24 hours or time recommended by the manufacturer.

This entry was posted in Concrete, Pole Building How To Guides, Pole Barn Planning and tagged condensation, concrete sealer, pole building concrete sealer, post frame condensation on February 6, 2019 by admin.

Foil Insulation is Not Insulation

Foil Insulation Is Not Insulation

Products being incorrectly marketed and sold as “foil insulation” are actually nothing more than a radiant reflective barrier. They are not insulation. I have previously covered this very subject, so will not rank and rail more: https://www.hansenpolebuildings.com/2014/04/reflective-insulation-wars/

Today’s learning article has inspiration in this from reader BOBBY in GRASSTIN who writes:

“I have a 24×36 Morton Pole building built in early 80s. I am trying to insulate and heat the building. Currently I have ridge vent and soffit vents. I was not intending on putting a ceiling under the trusses. This fall I lined the whole building roof and walls with foil insulation and hung 2 natural gas infrared heaters as a temp fix. I currently have two 9×7 overhead garage doors which are un-insulated and leak pretty much on all sides and a sliding door on the table end which leaks. Needless to say my gas bill is atrocious and because I sealed the ridge vent and soffit vents with foil I have a bad condensation problem mostly because the heaters put out so much water. Aside from sealing the doors with new insulated doors, how should I tackle the insulation and the condensation problem? Do I spray foam the roof and leave the vents plugged? Or spray foam the roof and install ceiling and unblock the soffit and ridge vents? Or spray foam ridge and soffit vents and install Gable vents? Which would probably be cheaper than a ceiling. Would I lose all my heat out of the Gable vents? Newbie here and appreciate the help.”

Mike the Pole Barn Guru responds:

Lots of things happening here, so let’s dive right in.

Ditch your current heaters and replace them with vented units. There are efficient vented gas heaters available, providing same type of heat you are used to, but they exhaust all their combustion by-products outside through a wall vent. You’ll lose not only water vapor, but also carbon monoxide, nitrogen dioxide and other contaminants.

Use a high quality sealant over your building’s concrete floors: https://www.hansenpolebuildings.com/2018/11/siloxa-tek-8505-concrete-sealant/.

So far we have eliminated sources of most condensation, moving next to how to best insulate what you have.

Chances are very small your building’s trusses will support a ceiling. This would have been an ideal case, as it would have kept you from having to pay to heat an area above truss bottom chord level.

Replace your present overhead and sliding doors with insulated overhead doors. Tear out foil “insulation” and throw it away. Keeping eave and ridge vents sealed, use closed cell spray foam insulation across walls and underside of roof deck. An absolute minimum thickness will be two inches, providing approximately R-14. You will need to weigh benefits of greater R values against investment.

Me – if allowed by my Planning Department I would build another building properly designed to be energy efficient. Chances are it will be comparable in investment to what you are going to throw into a three decades old building, plus it will be brand new!

This entry was posted in Pole Barn Structure, Ventilation, Insulation, Pole Barn Questions and tagged insulation, condensation, soffit vents, gas infrared heater, vented gas heaters, floor sealant on January 23, 2019 by admin.

A Steel Ceiling, Wall Finishes, and Condensation

Today Mike addresses questions about steel ceilings, options for wall finishes, and condensation in added space.

DEAR POLE BARN GURU: I have a 40ft wide x 60ft long x 12ft high pole barn. The trusses are 4ft on center. I want to put a steel ceiling up and wanted to know the best size piece to use when putting it up. 8, 10, or 12. MICHAEL in TABERNACLE

DEAR MICHAEL: Before consider this move confirm your trusses are designed to support added ceiling weight across bottom chords. Also, make certain to adequately ventilate dead attic space you will be creating (read about adequate ventilation here: https://www.hansenpolebuildings.com/2018/03/adequate-eave-ridge-ventilation/).

Having satisfied above, if you intend to merely attach steel panels to truss undersides and run panels lengthwise, I’d go with 28’ and 32’ long pieces to minimize splices. If framing has been placed between trusses to support steel running across building, go with full length panels and have no splices.

DEAR POLE BARN GURU: Hello.

We have a new pole building and are looking at options for finishing the interior walls. The building has been well insulated and will have a heater and AC unit. Besides drywall, what other options are available? LISA in MIDDLETOWN

DEAR LISA: Gypsum wallboard (sheetrock) will certain be most common as well as most popular option. If you go with 5/8″ thick Type X, it will also be fire rated. You can use any material for covering walls one would find in any type of building – however most of them are still installed over sheetrock. If for a shop building, 7/16″ OSB proves to be quite popular. Some people like steel liner panels, however I find them difficult to attach things like shelves and cabinets to and they get dented.

DEAR POLE BARN GURU: Greetings. I have a 20-year old 40×25 post and beam barn, 2 story, shiplap siding, with metal roof and concrete floor. Last summer I walled off a 11.5×25 area for a workshop (10ft ceiling) and noticed a lot of condensation this past spring (after pouring the concrete floor last fall). The workshop is used sporadically from spring through fall. I would appreciate your advice on how to address condensation issue and any recommendations for insulation. Thanks for your time. RALPH

DEAR RALPH: Your increase in condensation most likely comes from moisture leaving concrete as floor cures. If you placed a good vapor barrier properly under slab, it should eliminate this as a source of moisture for condensation. If you did not, then you will want to seal slab with a high quality sealant. If condensation issues continue, it may be necessary to add a powered exhaust vent. Click here for further reading about insulation for different post frame uses: http://www.hansenpolebuildings.com/2018/06/pole-barn-insulation-part-ii/

This entry was posted in Ventilation, Concrete, Building Interior, Pole Barn Heating, Insulation and tagged condensation, Ventilation, ceiling steel, wall finishes on December 24, 2018 by admin.

Will My Post Frame Building Support a Ceiling?

One of my frequently received questions – wanting to add a ceiling into a post frame building and wondering if the building will support the added weight. Other frequent questions include condensation issues and ventilation, so this reader has hit upon a trifecta.

Reader BRYAN in SWANTON writes:

“I am having some condensation issues. And I was curious about insulating the building. Also wanted to ask if my building is able to have a ceiling installed. Thanks for the fast reply.”

By any chance have you recently poured a concrete slab-on-grade inside of your building? If so, until concrete fully cures, it will expel a great deal of moisture inside of your building. Solution – open your doors to allow moisture to escape and keep them open until condensation issues no longer exist. Read more here: https://www.hansenpolebuildings.com/2018/01/condensation-roof-steel/.

If you poured a slab without a well-sealed vapor barrier underneath, it will contribute to excessive moisture challenges. If no vapor barrier, top of slab should be sealed: https://www.hansenpolebuildings.com/2018/11/siloxa-tek-8505-concrete-sealant/

Your new post frame building and its trusses were not ordered to be able to support the added weight of a ceiling. It may be possible to upgrade your trusses with an engineered repair to be able to carry a bottom chord dead load of five psf (pounds per square foot) or more. Plan upon an investment of $295 (plus sales tax if applicable), even if a truss repair cannot be designed. Contact Justine at justine@hansenpolebuildings.com if you are interested in going this route.

If you are able to get a repair to install a ceiling, this newly enclosed attic area will need to be adequately ventilated. This may be a possible solution: https://www.hansenpolebuildings.com/2018/07/my-pole-barn-needs-ventilation/

In order to insulate, best solution (although costly) may be to use closed cell spray foam insulation. If you purchase an insulation kit for your overhead door, you will need to change out door springs in order to handle the added weight.

This entry was posted in Trusses, Ventilation, Building Interior, Insulation, Pole Barn Questions, Pole Barn Structure and tagged condensation, truss repair, attic, Ventilation, attic ventilation system, closed cell spray foam on December 18, 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 Pole Barn Questions, Pole Barn Planning, Ventilation, Concrete and tagged insulation, vapor barrier, condensation, mold, moisture issues on October 24, 2018 by admin.

Examining a Light Steel Truss Frame Building

I have never owned or assembled a light steel truss frame building. A gentleman named Stan Floyd worked for me as a salesman when I owned M & W Building Supply. Stan’s dad had fabricated light steel truss frame buildings in Arkansas and Stan was interested in developing this concept in Oregon and Washington. With my blessing Stan founded Web Steel Structures in Sandy, Oregon and found out things weren’t quite like they had been in Arkansas – where building permits, if even required, were issued far more liberally. Northwest jurisdictions required engineering for both frames and buildings, as well as a need for a higher degree of control over welder competency.

Reader DEBORAH in OMAHA writes:

“Did pic come through?

Does this look viable at 30+ years old?

Tear down? I’m looking at buying this property and I’m wondering if I’m going to be the one tearing this 180’ x 85’ building down…

There are only 4 bolts holding the truss frame together at center. Bays are 18’ on center. Every other bay has a criss cross bracing with wire (X) that is of steel cable – somewhat loose. I think there is another cross at the ceiling in kind of a strange place.

I believe the purlins are 2 x 8 as opposed to 2 x 10 which might be better. Building is in Southern IL near KY border.

I think this may have been a Cuckler kit. But I’m not sure. I’ve contacted Star Buildings to see if they know.

Thoughts?

I called an SE for a site visit and load calc and I know that will be about $12,000. It would be estimated as steel quality is unknown. Site visits for just a nod are about $900.”

Dear Deborah ~

Thank you very much for sending photos.

You are looking over a light steel truss frame building – not a post frame building. I am not a gambling man, however I would wager there was no actual engineering done for this structure to start with. Light steel truss frames, such as this, are also rarely engineered. More often than not, frame designs are just like daddy used to do them, so they must be good. Well, engineering does not quite work like this.

Some observations from your photos – minor discolorations appearing as “runs” down sides of roof purlins are due to condensation. No steel roofed building should be constructed without some sort of mechanism to minimize condensation. Only realistic fix for future condensation control would be to have closed cell spray foam insulation placed below roof surface. This insulation should be a minimum thickness of two inches and in most areas a going rate of about a dollar per square foot, per inch of thickness. You could be seeing a $30,000 bill.

Purlins with major blackness have mold due to roof leaks. This mold can be removed, but will prove to be labor intensive. I’d replace any roof ‘skylights’ with steel panels. If they have not yet begun to leak, they will in time.

Unless roof purlins are some grade higher than #2 & btr, they are over stressed in bending and likely have deflection issues. Chances are good wall girts have similar challenges.

In summary, if you decide to invest in this property I would recommend you not go inside this building when snow sticks to roof or winds are over 50 miles per hour. Insure it heavily (for non-depreciated replacement cost) and don’t keep expensive horses inside it.

For history buffs – Cuckler Building Systems division of Lear Siegler Inc. (LSI), was purchased by Star Manufacturing Company in 1986. With manufacturing locations in Monticello, IA and Turlock, CA, Cuckler had annual sales of approximately $20 million. Cuckler Steel Span Company had previously been acquired by LSI in 1970. I’d be interested in any stories about Cuckler Steel Span’s earlier years.

This entry was posted in Pole Barn Questions, Pole Barn Design, Pole Buildings History, Pole Barn Structure, Trusses and tagged condensation, skylights, spray foam insulation, Cuckler Building Systems, Star Buildings on October 23, 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 Insulation, Pole Barn Questions, Pole Barn Design, Pole Barn Planning, Ventilation and tagged cold storage pole barn, post frame cold storage, insulation, vapor barrier, condensation, polyiso, polisocyanurate on September 20, 2018 by admin.

Radiant Barrier, Wind and Hail, and Sliding Door Parts?

Mike answers questions about a adding radiant barrier, wind and hail, and parts for sliding doors:

DEAR POLE BARN GURU: I have an existing pole barn and want to add a radiant barrier to the inside walls before I insulate and cover the walls. Is this wise and can I use a foil that comes in a roll. Once attached there would be a 1 and 1/2 inch air space between the foil and the metal.

Thank you for any advice you would have with this. CANDICE

DEAR CANDICE: This would not be a good idea as you are creating a space between two vapor barriers in which condensation could occur and moisture problems develop. Your best bet is to remove the steel siding, one wall at a time, install a well sealed building wrap (like Tyvek), then reinstall the steel.

DEAR POLE BARN GURU: We get a ton of wind and hail throughout summer months. How will pole barn hold up to these conditions? REBECCA in PEYTON

DEAR REBECCA: Here are quick links to your answers:

Wind: https://www.hansenpolebuildings.com/2011/06/more-high-wind-news/

Hail: https://www.hansenpolebuildings.com/2011/09/steel-roofing/

DEAR POLE BARN GURU: Good morning. We have a Miracle Span Quonset, would you have 10 x 14 sliding doors that would fit it? KRISTEN in BRAINERD

DEAR KRISTEN: Thank you very much for your interest. We do have sliding doors which would fit, however due to shipping challenges we only provide them with the investment in a complete post frame building kit package. We would suggest you visit the ProDesk at your local The Home Depot®.

This entry was posted in Insulation, Roofing Materials, Steel Roofing & Siding, Sliding Doors and tagged condensation, sliding doors, radiant barriers, wind and hail, parts orders on April 9, 2018 by admin.

Fire Resistance, Condensation, and Wind Speed

Fire Resistance, Condensation, and Wind Speed

DEAR POLE BARN GURU: Do you know if WMP-10 metal building insulation facing is ok to have exposed in a commercial building in regards to its fire resistance rating? JON

DEAR JON: WMP-10 facings are flame resistant, however you should consult with your local building code enforcing agency to determine if they will allow it to remain exposed given your use of the structure. An alternative might be Johns Manville FSK-25 faced batts which are laminated with an FSK (foil-scrim-kraft) facing, which enables the insulation to carry a fire hazard classification rating of 25/50 or less per ASTM E 84. The FSK-25 facing also serves as an excellent vapor retarder and may be left exposed where codes permit. The FSK-25 batts are a lightweight fire-resistant thermal and acoustical fiberglass insulation made of long, resilient glass fibers bonded with a bio-based binder.

Personally, I’d look at using unfaced fiberglass or rock wool batt insulation then covering the interior surface with 5/8″ Type X gypsum wallboard. Probably less expensive and would afford greater R-values with less of an investment.

DEAR POLE BARN GURU: I recently had a small pole barn constructed in Northern NJ which I’m about to insulate. Needless to say, the information regarding this is very confusing. The end goal here is to not have a condensation problem. With no insulation on the walls currently the metal walls sweat. The roof consists of metal roofing on top of “double bubble” on top of purlins with ridge vent and soffit vents. The walls will be filled with 6″ fiberglass and a poly vapor barrier applied. The ceiling will either be OSB or gypsum attached to the bottom of the trusses with blown insulation on top with no vapor barrier. With that said, my question is with this configuration, will the gable ends above ceiling height sweat or do they need to be insulated? If so what would be the recommended insulation?

Thanks, CONFUSED in NEW JERSEY

DEAR CONFUSED: With proper ventilation in your attic I won’t say it will be impossible to have condensation on the inside of the attic gable endwalls, however the probability should be small. If you want to make certain, an inch of closed cell foam can be sprayed on the inside of the endwall steel and it will eliminate any chance.

DEAR POLE BARN GURU: Are your plans for stick built frames or CBS frames or both? If only for frame built what is the wind ratio? SUNSHINE in JUPITER

DEAR SUNSHINE: Our buildings are neither stick built or concrete block – they are post frame buildings.

Since January 1973 anemograph stations within the United Kingdom have tabulated for each clock hour the mean hourly speed and the maximum gust (of approximately three second duration). The ratio of maximum gust speed to the mean speed for individual hours as an effective height of 10 meters is referred to as the gust ratio. The mean wind ration is the ratio of the extreme gust speed to the extreme hourly mean speed, both having a return period of 50 years. This ratio turns out to be 1.60.

Here in the colonies, we design using Vult (Ultimate Wind Speed). Until the 2012 IBC (International Building Code) we designed for Vasd (Allowable Stress Design) which is 60% of Vult.

One of the beauties of post frame construction is the buildings can be designed to support any wind load situation needed.

This entry was posted in Insulation, Pole Barn Design, Steel Roofing & Siding, Ventilation and tagged Vult, Vasd, insulation, condensation, wind speed, Insulation fire resistance on April 2, 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 Pole Barn Questions, Pole Barn Homes, Pole Barn Design, Pole Building How To Guides, Pole Barn Planning, Ventilation, Building Interior, Insulation and tagged frost protected shallow foundations, pole barn house heating, vapor barrier, condensation, downspouts, rain gutters on February 6, 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 vapor barrier, A1V insulation, condensation, tear down, bay spacing, auto lift, car lift, rebuild on January 1, 2018 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 Trusses, Ventilation, Insulation, Pole Barn Planning and tagged truss loads, spray foam insulation, barriers, ceiling joists, vapor barrier, condensation on December 18, 2017 by admin.

Commercial Girts Best for Drywall, Site Prep, and Condensation

DEAR POLE BARN GURU: I’m considering a pole barn for my residence but had a question about the girt placement between posts. I read in the FAQ section that they are placed like shelves between posts. Would it be possible to mount drywall directly to these for interior walls without additional bracing or building of interior wall frames? I’m trying to avoid framing an entire building within a building, it seems pointless and not cost effective. If I need to frame every interior wall to hold drywall and insulation, I can simply build a standard stick frame house. VAN in INDEPENDENCE

DEAR VAN: Bookshelf girts for insulation (e.g. Commercial Girts) is a quick and easy way to create a deep insulation cavity as well as providing the framing for your interior GWB (Gypsum Wall Board). You will want to confirm your new post frame building frame is stiff enough to prevent undue deflection from cracking the GWB joints.

Learn more about commercial girts here: https://www.hansenpolebuildings.com/2011/09/commercial-girts-what-are-they/.

DEAR POLE BARN GURU: I have property in an area that floods from time to time. For example, can a monitor barn (approx. 25×50). with side sheds be built. The idea I have is the side sheds serving as porches and under the barn would be a drive through area. there is already a modular home built in the area that is elevated about 4 ft. off the ground and they have had no problem . Thanks, MIKE in MOLINA

DEAR MIKE: You can build any sort of post frame building on your site which will be allowable under the limitations of your Planning Department. As to dealing with the flood issues, you should have your property elevations determined by a surveyor, and the site where the building will be constructed can then be built up so the floor will be above the flood plain level.

DEAR POLE BARN GURU: I recently purchased several 4’x50′ reflectix double bubble foil rolls. I’ve put up a brand new 30×56 post frame metal building and was going to use this product to keep the metal roof and walls from condensating not to mention I was hoping it would help keep some heat in during the winter and heat out during the summer until I truly insulate the inside. My question is, for ease of installation on my metal roof panels, is it acceptable to put the foil on the underside of the 2×6 roof joists instead of sandwiching it between the roof joists and metal? There will be no roof venting due to leaving the trusses and attic space exposed. My only real concern is that it could condensate worse installing it this way. Also I will not be continually heating the building. Only on occasion with a propane heater while I’m working. I’m not real savvy when it comes to insulation and condensation control so any advice would be appreciated. Thanks in advance! Brandon

DEAR BRANDON: While it would be easy to install the steel roofing without having to place the reflective radiant barrier between the roof purlins and the roof steel, it is going to be the easiest method to limit condensation issues, given the product you have invested in. Hopefully you have gotten the double bubble with a tab along one side and an adhesive pull strip, otherwise you will have to tape all of the seams as you work your way along the roof.

Could you place it on the underside of the purlins? Yes, however in order to work as an effective condensation control, it has to be absolutely tightly sealed against any protruding framing members. Remember the time you saved on installing the roof steel? You just ate it all up.

If you have not yet ordered your steel roofing you could resell the reflective radiant barrier online and order steel with I.C.C. (Integral Condensation Control) attached (see the article and video here: https://www.hansenpolebuildings.com/2017/03/integral-condensation-control/).

This entry was posted in Building Interior, Pole Barn Homes, Uncategorized, Insulation, Steel Roofing & Siding and tagged drywall, Condenstop, elevations, site prep, condensation, girts on May 8, 2017 by admin.

How Can I Reduce Humidity?

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: Mr. Guru I was wondering if I could ask you a question about pole barns, because I have an issue with mine that is stressing me out. I live in Virginia and My pole barn/ 3 car garage was built in 2004 it is 28′ wide x 44′ long x 10′ tall, foil insulation roof and sides, 4″ concrete floor, gutters and downspouts, 3 insulated garage doors with 5 windows in each and an entry door. I have never noticed any moisture on my garage floor or anywhere inside in all these years, I have 2 classic cars and a 2005 truck that has never seen rain and only has 2,000 miles on it. When I went to change the oil I noticed pulleys under the hood are starting to rust along with bolts and suspension parts underneath. Could humidity be making it rust? I have a gauge in the garage that said 65 % humidity when the temperature was 85 inside. What would be my best bet to reduce the humidity?. Parking on plastic sheeting and a dehumidifier?. I also saw online where ridge vents and vented soffits help circulate air. Thanks for any reply. VAPORIZED IN VIRGINIA

DEAR VAPORIZED: While humidity does not cause rust directly, it does promote it. Rust formation will depend upon the carbon content of the steel, as well as the amount of oxygen in contact with the steel.

From my research, it appears 40% or lower humidity is optimal. In order to reduce humidity, the building needs to be sealed up fairly tight. If there is not a vapor barrier under the concrete floor, a high quality sealant should be put on it. A Tyvek or similar building wrap should be installed between the wall girts and siding. On the inside of wall insulation, a vapor barrier should be installed, taking care to highly seal all joints and corners.

Do not place a vapor barrier at ceiling level, as warm moist air will naturally rise through the ceiling drywall and into the attic space, which must be adequately ventilated (best method is enclosed vented soffits and a ridge vent).

Once these things are done, you may have to use a dehumidifier, but at least you have a space created which can be dehumidified.

A couple of products you may want to investigate to help remove or inhibit rust are Break Free CLP and Eezox.

Mike the Pole Barn Guru

DEAR POLE BARN GURU: Sort of a pole barn question, but actually a metal roof slope design question. I think your pole barn experience is more than enough to help me with this one.

I want to add a simple metal roof over my back deck.

The deck is 40′ long and projects 10′ out from the house.

Unfortunately, the slope has to be 1.5/12 for me to have 72″ height (bottom of joists) over the deck at the lowest end of the roof.

Can I meet adequate design using 2X6x10′ joists on 4′ centers with 2X4 purlins 24” OC using 28 gauge corrugated metal?

If not, should I use 3′ centers for joists or would you recommend 2′ centers?

Or is a 1.5/12 pitch not feasible in this application? I could go 2/12 pitch but the height at the lowest end of the roof trusses would only be 68″ above the deck level (a little too low for my taste).

Thanks Pole Barn Guru for any help you can give me. KAN I IN KENTUCKY

DEAR KAN I: Lots of issues going on here.

While light gauge steel roofing is a great product, it does have some limitations. If you are considering pre-painted (colored) steel, you should be aware of the warranty being void on slopes of less than 3/12.

You also should have a height of no less than 6’8” from top of decking to bottom of any framing which people could walk under (and 7’ would be better yet).

As to sizing of rafters (joists as you have called them), you can use Table R-13 at: https://www.awc.org/pdf/STJR_2012.pdf to determine adequate size and spacing based upon the live (snow) load at your particular site. You will need to know the Fb value of the material you propose to use for rafters. With Southern Yellow Pine (most common in your area) 2×6 #2 has a value of 1000 psi, 2×8 is 925 psi.

In either case, the 2×4 purlins at 24 inches on center will prove to be adequate.

You can read more about the Code requirements for patio covers here: https://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_apph_sec001.htm

Mike the Pole Barn Guru

DEAR POLE BARN GURU: I noticed that my light colored pole barn siding was getting a black coating (kind of looks like coal dust but it isn’t). I figured just some scrubbing with household detergent would remove it but I was wrong. It appears to have stained the paint.

Worried now that the staining is permanent. Barn is only about 10 years old. Any suggestions would be appreciated.

Thanks. STRAINING WITH STAINS

DEAR STRAINING: It really should not be stained. The following is our typical instruction, as recommended by the steel roll forming companies:

For homeowners accustomed to sanding and painting exterior walls (or paying to have done), the easy-care pre-painted steel roofing and siding convenience can lull one into complacency. But, like any outdoor material, steel siding and roofing does get dirty – dirty enough, in fact, to be cleaned at least once a year.

Dirt pickup may cause apparent paint discoloration when exposed, in some dirt-laden atmospheres, for long time periods. Slight chalking may cause some change in appearance in strong sunlight areas. A good cleaning will generally restore the building appearance and render repainting unnecessary. An occasional light cleaning will help maintain good appearance.

To maintain original building panel finish, the only regular maintenance necessary is an annual washing. Remove airborne dirt and weather-related streaks with a garden hose or pressure washer and a bucket of sudsy water. If rinsed frequently, a garden hose may be all which will be needed to use.

Light panels may be washed with either mild detergent-type cleaners or by steam and high pressure spray systems. Apply cleaners with sponge or soft brush and rinse thoroughly in cold water to eliminate cleaning agent film build-up. Follow cleaning agent manufacturer’s instructions. Test small area before applying over entire surface. Hard water deposits may be removed with a 10% acetic acid solution in cold water. Rinse thoroughly.

Mike the Pole Barn Guru

This entry was posted in Pole Barn Questions and tagged how to clean a metal roof, deck covers, how to wash steel, patio cover, roof only deck covers, washing steel, condensation on November 3, 2014 by admin.

Roof leaks: Where does condensation come from?

Roof Leaks: Where does condensation come from?

When the weather turns cool in the fall, we get calls from customers with “roof leaks”, even when it has not been raining. These “leaks” are actually from condensation and are often reported as, “My steel roof is sweating”.

Steel roofing does not sweat. Having no sweat glands, it cannot produce moisture on its own. Condensation is a result of warm, moist air coming in contact with anything below the temperature of the dew point.

A classic example – ice cold beer on a warm day, moisture forms on the outside of the glass. The beer glass is not sweating and probably not leaking. It is just colder than the dew point causing moisture from the warm air to condense on the outside of the glass. Glass cannot absorb moisture, causing water droplets to trickle down the sides of the glass, creating a puddle or ring around the base.

Like glass, steel does not absorb moisture. Condensation, forming on the underside, falls off and drips on everything below. As steel is a heat conductor, it gets to the same temperature as the outside air very quickly.

Where does this moisture come from? Even in naturally low humidity climates, some degree of moisture is always in the air. You, as well as any animals housed in your building, produce a tremendous amount of water vapor, merely by exhaling. However, most of the moisture is coming from the ground beneath your building.

Do you believe concrete is a solid? Concrete actually acts far more like a sponge, soaking up moisture from below and allowing it to pass through into your building. Check out a concrete floor when frost is coming out of the ground and the air is warmer above.

Try this experiment either on a humid day this summer, or on a cool day this fall – lay a piece of cardboard on the concrete floor in your building overnight. The next morning lift the cardboard, the underside will be damp from moisture passing through the concrete slab!

Reflective radiant barrier will prevent most condensation

OK, so what do you do about condensation issues in a building? If the roof has steel siding, this is actually pretty easy. We put a condensation barrier under the steel, such as reflective radiant barrier. This has white vinyl on one side and aluminum facing on the other, to reflect heat from the sun, with a layer of air cells sandwiched in between. It’s actually the air cells doing all the “no condensation” work by creating a thermal “break”. Bonus points are having deflection of heat with the silver surface, making the building cooler. And yes, this reflective radiant barrier does have a very minimal “R” value.

Back to the water issues. Putting just plastic sheeting or house wrap on your building won’t do the trick against condensation. You need a thermal break between the warm air and the steel. And down the line in another blog, I’ll discuss building ventilation to decrease condensation as well. For now, just keep in mind roof “leaks” don’t have to happen.

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This entry was posted in Pole Building Comparisons, Pole Barn Structure, Steel Roofing & Siding and tagged condensation, roof leaks, steel roofing on August 16, 2011 by admin.