Home >> rock wool

Tag Archives: rock wool

A Radiant Barrier Issue, Venting in Humidity, and Frost Walls

This week the Pole Barn Guru answers reader questions about insulating a building that already has reflective foil radian barrier, if one needs vents or exhaust fan in the gable ends of the roof with the high heat/humidity of Alabama, and requirements for frost wall or slab for frost heave.

DEAR POLE BARN GURU: I recently moved into a house with a 40×30 pole barn (wood post and wood trusses) with a metal exterior. The building has a reflective foil radiant barrier between the metal and wood structure. It is extremely hot in the summer and cold in the winter. I want to insulate and cannot afford spray foam. I also don’t have the ability to remove the walls to remove the foil barrier that way. I do have some Silvercote insulation that has an attached vapor barrier. It is just a fiberglass roll insulation that has an attached vapor barrier to it. It is sold around here for use as insulation in metal buildings. I was given enough to insulate the whole shop from someone that had left overs. I would like to install this insulation to help with temps in the shop. I have tried to research to get an answer on the best way to go about this. The shop builder said just put it up but I feel that would create a double vapor barrier. Is my best route to cut the foil radiant barrier out and then install the fiberglass insulation with vapor barrier facing the interior of the building? This would basically take the foil barrier out and install the fiberglass against the metal with the attached face vapor barrier to the inside of the building. I want to make sure I do it right. Thank you. DAVID in OKLAHOMA CITY

DEAR DAVID: If you are dead set on using this Silvercote insulation then you should cut out any foil radiant barrier. You never want to have a double vapor barrier situation as any trapped moisture will have no method of escaping. Downside of this is you do not have a Weather Resistant Barrier (aka housewrap) between framing and siding. An option to consider would be to resell your metal building insulation, then use unfaced Rockwool batt insulation, as it is unaffected by moisture.

DEAR POLE BARN GURU: I plan to build a 28×48 metal pole barn, concrete floor, 12′ eave with 8/12 pitch. Barn will have 6 3×4 windows, and two 10×10 roll doors, one roll door on each gable end. For now, the roof will be insulated with 3in closed cell foam. I plan to insulate the walls down the road with rigid foam board. The building will not have A/C. Question: Do I need vents or exhaust fan in the gable ends of the roof with the high heat/humidity of Alabama? There will be no ridge vent or soffit vents. I may not have the building open every day, either. Thank you. JASON in MONTGOMERY

DEAR JASON: While placing permanent vents might alleviate your possible mold/mildew/condensation issues, they will defeat your insulation investment. In reality, you should look to a qualified local HVAC provider to provide mechanical dehumidification, else you will have regrets forever. Make sure to have a vapor barrier under your concrete floor, to help reduce interior moisture gain.

DEAR POLE BARN GURU: FROST HEAVE, 44′ deep by 64 long pole barn 20 ceiling height, Tenant build, will be insulated but NO HVAC initially. However, is some type of concrete frost wall (downturn?) via monolithic slab required? Dimensions? MIKE in CINCINNATI

DEAR MIKE: Your slab on grade can be poured to a consistent thickness throughout and all you need to do is properly insulate your slab edge to meet IECC (International Energy Conservation Code) requirements.

This entry was posted in Barndominium, Building Interior, Budget, Pole Barn Homes, Insulation, Pole Barn Questions, Pole Barn Planning, Pole Barn Heating and tagged insulation, reflective radiant barrier, frost heave, Ventilation, rock wool, monolithic slab, exhaust fans, gable vents, frost wall, moisture barrier, humidity on July 9, 2025 by Rick Ochs.

Stilt Home Barndominium

For many challenging building sites (those with grade change, in flood zones or close to oceans or seas) stilt homes are a viable and practical design solution for barndominiums.

Reader DAVID in EMINENCE writes:

“We are planning to build in southern Missouri a 30′ x 36′ x10′ post frame home on a rocky slope terrain. We want it on stilts. It would be 3′ on one end and 7′ on the other end approximately. We are planning to put reflective bubble wrap on the floor joists with the subfloor on top then place down rock wool and another subfloor on top. We have 99% humidity most of the year (10 months for sure), lots of rain. We do not want a crawl space; we know the horrors of the crawl space. We may enclose the high end using a simple temporary enclosure to dry it out as needed. We are going to use a mini split heating system and composting toilets. No worries about placement of the utilities and pests. Would this be a sound construction system?

We would like to know your viewpoint on this since you are the wise guru.”

Mike the Pole Barn Guru writes:

Thank you for your kind words. Stilt houses are very easily done using post frame. I have a post frame combination garage/studio apartment/office at our home near Spokane, Washington on 14 feet of grade change and built it as a stilt building. Has been great for going on 30 years and would have been the only practical way to build on this site (for extended reading on stilt houses: https://www.hansenpolebuildings.com/2017/09/stilt-houses/).

Not sure why you are considering two layers of subfloor. I would be inclined to use either steel or an exterior rated sheathing product on the underside of my joists (with a Weather Resistant Barrier between). Rock wool is a good choice for insulation between joists as it is not affected by moisture. Place a vapor barrier on top of joists and then your subflooring. A radiant reflective barrier (bubble wrap) can be used as a vapor barrier, but will not provide any benefits you wouldn’t get from well-sealed visqueen – and would be far more expensive.

This entry was posted in Post Frame Home, Barndominium, Insulation, Pole Barn Questions, Pole Barn Planning, Pole Barn Homes and tagged reflective barrier, mini split heating system, stilt houses, subfloor, rock wool, visqueen, reflective radiant barrier on June 5, 2025 by Rick Ochs.

Insulation in Massachusetts, Code Restrictions in MN, and Insulation for In-Floor Heated Building

This Wednesday the Pole barn Guru answers reader questions about the best options for insulating a 24×30 pole barn, potential code restrictions in Victoria, MN, and Insulating a building with radiant floor heating.

DEAR POLE BARN GURU: Hello, I want to insulate my 24’x30′ pole barn located in Massachusetts. I will heat it only occasionally. I have decided due to budget and other considerations to use 2″ thick closed-cell foam in the walls. I am unsure whether to piece the foam between the bookshelf girts and place it up against the steel siding, or on the inside of the flatwise girt, leaving a 1 1/2″ gap between the foam and siding. In either case I will be sure to seal all the joints well with spray foam. I’m thinking the second option would be better to avoid trapping moisture between the foam and siding. I suppose a third option would be to install the foam on the inside of the bookshelf girts leaving a 5″ air space. This option has the benefit of eliminating the thermal break created by the girts. Which option do you recommend? DAVID in WESTFIELD

Just when you think you have everything figured out, along comes me and picks Door D.

What? There is no Door D….

Air gaps in walls are problematic, they allow moisture to gather, drafts to occur and fire to rapidly spread.

My recommendation is to completely fill this cavity with Rockwool. It does not burn, is not affected by moisture and critters will not try to live or nest in it. You will want to have a vapor barrier on interior face, between framing and wall finish.

For extended reading: https://www.hansenpolebuildings.com/2013/03/roxul-insulation/

DEAR POLE BARN GURU: I live on an acre within the city limits of Victoria, MN does the code allow pole barns as a detached garage? MARK in VICTORIA

DEAR MARK: A permit issuing jurisdiction cannot legally restrict a code conforming structural system, however your Planning Department may have restrictions in regards to setbacks, footprint and even allowable types of roofing and/or siding. You will want to reach out them directly: https://victoriamn.gov/government/community___economic_development/index.php (contacts and phone numbers are at left side of page).

This should prove helpful further reading: https://www.hansenpolebuildings.com/2013/01/planning-department-3/

DEAR POLE BARN GURU: What Options other than spray foam for insulating a pole barn ceiling up against the roof peak to keep the trusses exposed? Building has Prefabricated wood 2×6 trusses 4′ apart with wood 2×4 purlins against the metal roof. Building has no vaper barrier. Planning on doing 2 layers of insulation on the walls. First layer 2″ Foil faced EPS foam board against the girts (not between the girts) with taped seams. Second layer 3 1/2″ mineral wool. The 2 layers will fill the 5 1/2″ cavity between the 4×6 posts. Should the walls have a plastic vaper barrier on the inside after the mineral wool? Or is the first layer of EPS foam board act as a vaper barrier? Building will have radiant floor heating. I Appreciate your thoughts, Thanks! PETER in MANAHAWKIN

DEAR PETER: You have no option but closed cell spray foam applied directly to underside of roof steel, if you want to leave trusses exposed. Otherwise, you would have to provide an inch of clear airflow from eave to ridge directly below roof deck – impossible with purlins blocking this flow. A better option would be to install a ceiling (provided your trusses will support this added weight) and blow in granulated Rockwool or fiberglass (this does require vented eaves and ridge in correct proportions). Why better? You will not be heating a huge volume of space above your truss bottom chords. You should, however, still spray enough closed cell spray foam on underside of roof deck to prevent condensation (2 should do it).

Your sealed foam boards are now your vapor barrier, so you will want no interior vapor barrier. This combination, along with spray foamed roof deck, will cause your building to ‘dry’ to inside. Expect to have to mechanically dehumidify, or face mold and mildew issues.

This entry was posted in Roofing Materials, Barndominium, Pole Building How To Guides, Pole Barn Planning, Ventilation, Building Interior, Budget, Insulation, Pole Barn Questions, Pole Barn Heating, Building Department and tagged rock wool, rock wool insulation, building codes, Minnesota Codes, pole barn insulation, Municipal Codes, pole barn ceiling insulation, closed cell spray foam on March 19, 2025 by Rick Ochs.

Insulating a Shed, Addition of Eave Light Panels, and a Small Well Building

Today’s Ask the Guru answers reader questions about insulating a shed used for vehicle storage and a “workshop to piddle in,” the addition of eave light panels to a structure, and if it is possible to build a small building to house a well.

DEAR POLE BARN GURU: Thank you in advance for your time to answer my question! I have a 30×40 x12 pole building that I want to insulate. This will be used to store my vehicles in and to

have a workshop to piddle in. Want to have a mini split system to heat or cool only when I’m out in the shop. I have Tyvek between the metal siding and purlins on the walls. I have a ridge vent the entire length of the building with the condensation barrier under the metal roof panels. I just started to frame my walls 16″ OC for batt insulation and was going to put up metal panels

on the ceiling and lay batt insulation on that. Is this ok and/or should I add vapor barriers anywhere. What are your thoughts on this? Thanks again MARSHALL in SALISBURY

DEAR MARSHALL: You will need to have an appropriately sized air intake (either eave or gable vents) in order to prevent possible mold and/or mildew in your attic. Use unfaced batts (Rockwool would be my preference, with fiberglass second). Your walls will need a vapor barrier, ceiling will not.

DEAR POLE BARN GURU: I would like to put in polycarbonate “windows for my eve light on a 36×56 pole barn. The light vents will be on the east side of the pole barn. I would like to do this myself. Do you have a simple how to or a video? These are NOT on the roof. HOLLY in MILACA

HOLLY: We can provide 19 pieces of 3′ net width coverage by 3 feet tall polycarbonate panels, as well as steel “z” flashing needed for your transition from polycarbonate to steel siding and appropriate screws to attach. Along with this, you will get a Chapter from our Construction Manual to detail installation. To save on delivery costs, we can have these all available for you at our Browns Valley, MN facility. Please reach out to Materials@HansenPoleBuildings.com for pricing.

DEAR POLE BARN GURU: Have residential well, need a small building has this been done? CHRIS in ELMGROVE

DEAR CHRIS: Yes, it has been. Post frame (pole) buildings start to lose economy of scale as footprint dimensions decrease. Below roughly 24 feet square, other forms of construction may prove to be more cost effective. A factor playing into this is most jurisdictions exempt from building permits structures below a minimal square footage.

This entry was posted in Skylights, Lumber, Insulation, Pole Barn Heating, Pole Barn Questions, Barndominium, Pole Barn Design, Pole Barn Planning, Building Interior, Budget and tagged eave lights, rock wool, heated shop, insulation, residential well building, polycarbonate eave lights, Ventilation on December 11, 2024 by Rick Ochs.

Housewrap, Roof Insulation, and Ceiling Fasteners

This Wednesday the Pole Barn Guru answers reader questions about a home owner asking builder to install housewrap on the roof, the best solution to insulate underside of roof, and what the best fastener for screwing steel to ceiling or roof trusses would be.

DEAR POLE BARN GURU: Pole Barn Guru, thank you for your knowledge. I have a customer wanting house wrap around the exterior of a 30×40 pole barn. Is house wrap to be installed in between purlins and roof steel or will I need a radiant barrier to prevent condensation? Home owner says house wrap on the roof as well but I’m not sure if that’s the route he really wants to go. House wrap on side walls in between girts and side steel is also the best route correct?

Thank you for your kind words, they are much appreciated. Provided your client will not be doing closed cell spray foam on walls, use house wrap between girts and wall steel. For his roof, housewrap is totally incorrect, as it allows moisture to pass through and become trapped between wrap and roof steel – potentially causing premature degradation. If your client is not closed cell spray foaming directly to roof steel, then order your roof metal with an Integral Condensation Control factory applied (Dripstop, Condenstop or similar) https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/. If roof steel has already been ordered (again assuming no closed cell spray foam being applied), then you do need some sort of a thermal break – such as a well-sealed radiant barrier.

DEAR POLE BARN GURU: Hi Mike, I built a 32’X40’X12′ pole building, (Shop) I used 1 1/2″ foam board on the inside walls, (on the inside of the girts) I can’t decide how I should insulate the underside of the roof. I have had a couple Spray Foam guy’s quote it , that’s pricy. Of course, the best R Value etc. at the most reasonable price is what I am looking for. In some of your post you have mentioned Rockwool that has gotten my attention. I see they make it up to R30. One thing that sticks in my mind is, my builder suggested not to use an insulation that will give insects a place to live. What would be your suggestion for underside of Roof insulation. Thank you. JIM in SPRING HILL

DEAR JIM: If your building has no current provision for controlling condensation on underside of roof steel, then two inches of closed cell spray foam applied directly to steel is your best insulation option. If you desire a greater R value, you can go thicker, or add open cell.

DEAR POLE BARN GURU: What screw is best for installing metal panels on the ceiling to wood trusses. MICHAEL in WENTZVILLE

DEAR MICHAEL: Most people are using #9 or #10 diameter 1″ screws. If you have ceiling framing 24 inches on center and want to utilize strength of ceiling liner panels to help transfer wind shear loads, then 1-1/2″ long diaphragm screws would be a better design solution.

This entry was posted in Ventilation, Uncategorized, Insulation, Building Interior, Pole Barn Questions, Pole Barn Design, Pole Barn Heating, Roofing Materials, Pole Building How To Guides, Pole Barn Planning, Post Frame Home and tagged spray foam, ceiling steel fasteners, roof insulation, condensation control, drip stop, Condenstop, screws, housewrap, rock wool on January 31, 2024 by admin.

Does My Pole Barn Need a Vapor Barrier?

Does My Pole Barn Need a Vapor Barrier Above the Metal Ceiling?

Reader DAVID in BALDWINSVILLE writes:

“I have a new pole barn with bubble vapor barrier under roof metal. I am installing a metal ceiling with R-38 cellulose in the attic. Do I need a vapor barrier above the metal ceiling? The barn will be heated somewhat in winter.”

From Mike the Pole Barn Guru:

Kudos to you for recognizing bubble wrap products advertised as ‘insulation’ are, at best, a good vapor barrier if properly sealed!

My son Brent is working on his doctorate at UMass Amherst, so I utilized Building and Construction Technology information from their Department of Environmental Conservation in penning this response.

My concern is with blowing in cellulose above a steel ceiling. From UMass:

“Wet insulation of any stripe is bad. But cellulose is hygroscopic. It’s able to soak and hold liquid water. Undetected leaks can wet cellulose causing it to sag within framing cavities. Water leaks can compress the blanket of fiber and in extreme cases, can create a void space, degrading its thermal value. Another concern is that chemicals used to protect cellulose from fire make it potentially corrosive in wet environments. Tests conducted by the Oak Ridge National Laboratory show chemical treatments used to treat cellulose can cause metal fasteners, plumbing pipes and electrical wires to corrode if left in contact with wet, treated cellulose insulation for extended periods of time. “

I’d much prefer to see you blowing in rockwool as it remains unaffected by moisture. Last thing you want is to have damp cellulose insulation chemicals eating holes in your ceiling.

According to building scientist and founding principal of Building Science Corporation Joe Lstiburek, “Plastic vapor barriers should only be installed in vented attics in climates with more than 8,000 heating degree days.”

As your site has under 8000 heating degree days a year, you should not have a ceiling vapor barrier. You do need to ensure your newly created non-conditioned dead attic space is adequately ventilated at eave and ridge (https://www.hansenpolebuildings.com/2018/03/adequate-eave-ridge-ventilation/).

For extended reading on heating degree days, please see: https://www.hansenpolebuildings.com/2022/11/what-is-degree-day/

This entry was posted in Insulation, Pole Barn Questions, Pole Barn Planning, Pole Barn Structure, Ventilation, Building Interior and tagged metal ceiling, vented ceiling, cellulose insulation, rock wool, ceiling vapor barrier, rock wool insulation, heating degree days on January 3, 2023 by admin.

Replacing Panels, Rebar in Column, and Wholesale Purchases(?)

This Wednesday the Pole Barn Guru answers reader questions about replacing old steel panels and adding an overhead garage door, if rebar is needed in the column to collar connection of the footing, and the ability to buy rock wool insulation wholesale.

DEAR POLE BARN GURU: I’m purchasing a small farm in rural Missouri. It has a 24′ x 60′ pole barn. the framing / structure is in good shape. It has corrugated metal panels. these are sound, but the looks are poor. It also has the sliding barn type door. My hope is to re-face the building with better looking panels and put in an overhead-style door ( garage type door). JOHN in NEWINGTON

DEAR JOHN: New steel cladding would certainly “freshen up” looks of this building. It would also allow for steel siding to be held up from grade (by adding a pressure preservative treated splash plank at base), rather than being run into ground.

DEAR POLE BARN GURU: Does rebar need to be installed in the concrete that surrounds the column in a pole barn? I will have holes of 12″, 18″ and 24″. Thanks. LOUIS in STEPHENS CITY

DEAR LOUIS: Unless it is called out for on your engineer sealed plans, there would usually be no requirement for rebar in concrete column encasement.

A 12″ diameter hole would be very unusual as Codes require a 4″ minimum space between corners of columns and edge of holes (a 4×4 perfectly placed in the center of a 13″ hole would meet Code requirements).

DEAR POLE BARN GURU: Hi, I was watching a video on Youtube recently and saw a guy hanging 6″ rock wool batt insulation. I was wondering if you might know where I can buy this product wholesale? I built a 30×64 and am at that stage where I’ll be looking to insulate myself soon. MARK in ARAPAHOE

DEAR MARK: Unless you are willing to buy an entire 53′ van box of rock wool, you are not going to be able to purchase it wholesale and even then you would need to provide proof you would be distributing on a regular basis from an established business in construction supply trades.

This entry was posted in Constructing a Pole Building, Pole Building Siding, Concrete, Footings, Insulation, Pole Barn Questions, Roofing Materials and tagged splash plank, steel panels, rebar, footing, rock wool, concrete collar, wholesale on December 21, 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 Building Interior, Insulation, Pole Barn Questions, Roofing Materials, Pole Building How To Guides, Pole Barn Planning and tagged spray foam, thermal break, closed cell spray foam, rock wool, PEMB, steel purlins, insulation, vapor barrier, condensation on August 25, 2022 by admin.

Stilt Home Barndominium

For many challenging building sites (those with grade change, in flood zones or close to oceans or seas) stilt homes are a viable and practical design solution for barndominiums.

We would like to know your viewpoint on this since you are the wise guru.”

Mike the Pole Barn Guru writes:

This entry was posted in Insulation, Pole Barn Questions, Pole Barn Planning, Pole Barn Homes, Post Frame Home, Barndominium and tagged stilt houses, subfloor, rock wool, visqueen, reflective radiant barrier, reflective barrier, mini split heating system on March 25, 2020 by admin.

enable JavaScript

1.866.200.9657

Latest Blog Posts

View All

Tag Archives: rock wool

A Radiant Barrier Issue, Venting in Humidity, and Frost Walls

Stilt Home Barndominium

Insulation in Massachusetts, Code Restrictions in MN, and Insulation for In-Floor Heated Building

Insulating a Shed, Addition of Eave Light Panels, and a Small Well Building

Housewrap, Roof Insulation, and Ceiling Fasteners

Does My Pole Barn Need a Vapor Barrier?

Replacing Panels, Rebar in Column, and Wholesale Purchases(?)

Can No Longer Afford Spray Foam for a PEMB

Stilt Home Barndominium

What will you use your

building for?

Approximate

building dimension

Your building. Your way.

Your building. Your way.

Can we text you to setup

appointments?

Are you a

robot?

Your request has been received!

Thank you!

There has been an

error!

Building KitPrice

Pole Barn Guru Blog

Ask The Guru

Pole Building Learning Center

Photo Gallery

Paint Your Building

Most Viewed Blogs

Latest Blog Posts