Tag Archives: post frame insulation

Insulate a Post Frame Building, Ventilation, and Column Sizes

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

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

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

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

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

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

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

Walls: From out-to-in:

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

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

 

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

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

 

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

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

 

 

 

 

Wall Insulation for a Hybrid Building

Wall Insulation for a Hybrid Building

Reader MASON in HILLSBOROUGH writes:

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

Thank you very much for your kind words!

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

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

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

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

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

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

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.

How to Best Insulate an All-Steel Building

How to Best Insulate an All-Steel Building

I know lots and lots about post frame buildings, however when it comes to all steel buildings (PEMBs – Pre-Engineered Metal Buildings aka Red Iron) I go to an expert.

Today’s expert is John Lyle McInroe aka Mr Bee Happy, he has been in the building industry since 1988. From 1988 to 1996 he built pole Barn structures. In 1996 he built his first steel building and for eight years built both pole Barn and red iron structures. In 2004 he went into red iron full time and has been building red iron structures of all shapes and sizes ever since. If I was looking for a red iron building in John’s service area, with out question he would be my man.

The most effective way to seal your steel building would be to use spray foam. Since the steel sheeting is already screwed down, I would start with getting closure strips for your panels. You take the closure strips and cut the high rib part off the strips and stuff it in all the high ribs of your panels. This would need to be done at the bottom and top of your sidewall panels and on the bottom and top of your roof panels as well. You want to make sure that anywhere you see daylight is sealed up. I would also use silicone to seal these closure strips into place. Also, just for a little extra, I would also use a flashing tape on any spots that you see daylight that isn’t necessarily where high ribs are. Places like gable end walls where roof and wall come together and corners. Simply, just want to make sure its sealed as well as possible. Once everything is sealed, I would have a reputable spray foam company spray two inches of closed cell foam on all walls and roof and make sure all steel is covered with the closed cell foam. This would include all purlins girt and beams. At this point you have sealed the envelope of the building but have a low R value, roughly 14. So what we do is use an open cell foam on top of the closed cell. We do 5.5” in the roof with 3.5” in the walls. At this point you have an R value of over 33 in the roof and 26 in walls and you have sealed the envelope. Now when we use this method on our projects, we make sure our HVAC company knows how to put in proper HVAC system. Main thing is making sure the system has a fresh air intake system. These are the processes and procedures that we use on all of our projects.

 

My New Barndominium

Reader RENE in MICHIGAN is one of a growing tide of Americans looking to build a barndominium. She writes:

“I would like to build a barn with living quarters but I do have unanswered questions!

My property is in Riverside WA 98849 and therefore the first question is whether you service this area?

I have done a lay-out of what I have in mind but with no prior experience, help would be appreciated to point out possible problems or suggestions for improvements.

Would a wood construction be preferred to metal?

Would a wood construction be more affordable than metal?

Would a wood construction be better insulated than metal?

Would my 70′ x 70′ building be more expensive than a smaller downstairs and upstairs building

I am in my senior years and still in very good health but there will be a day when using stairs may become a problem and that is why the square footage is so much. The living quarters are two bedrooms (guest bed 15’x20′, bath 15×10′, laundry 15’x10′)(main 20’x20′, bath 20’x10′,dressing room 20’x10′) 2 bathrooms and open plan Livingroom and kitchen (35’x40′) and would be 70′ x 40′ and the garage/storage/RV space 70′ x 30′

May have more questions later but would like to start off with the most obvious, for me. I have to sell property in MI before I can get going on this side. If you could correspond with me by email, for starters, I would appreciate it. 

Thanks, take care and stay safe!

“GodBless”


Mike the Pole Barn Guru responds:

About Hansen BuildingsThank you for reaching out to us. I also qualify for those senior discounts and fully understand stair issues. When we built our own shouse (shop/house) in Northeast South Dakota 15 years ago we went with two stories and my lovely bride insisted upon having an elevator (we actually now have two of them).

I know Riverside well. Back in my younger days I was a prolific post frame builder based in Spokane. There was one year where we erected over 200 post frame buildings just in Spokane County! Hansen Pole Buildings happens to not only service Riverside, we provide more post frame buildings in Washington than any other state!

In my humble opinion wood post frame is going to have numerous advantages to a PEMB (pre-engineered metal building). While building shell costs are probably similar, it ends there. It is going to be easier to construct without a need for heavy equipment. Our post frame buildings come fully engineered including engineered foundation plans (PEMBs require you to hire another engineer to design foundations). Concrete slabs for PEMBs require significant amounts of rebar, resulting in much greater foundation investments. To have a home inside a PEMB, most usually one has to build a framed home inside of a building shell – unlike post frame where you only have to do it once. Post frame buildings are easily super insulated, whereas PEMB steel frames are a great thermal transfer. My ultimate guide to post frame insulation is here: https://www.hansenpolebuildings.com/2019/11/post-frame-building-insulation/.

I have also written about one story or two: https://www.hansenpolebuildings.com/2020/02/barndominium-one-story-or-two/

Here are a few plan tips to consider:

Direction of access (you do not want to have to drive around your house to access garage doors.)
Curb appeal – what will people see as they drive up?
Any views? You’ll want to access all windows with great views to look at.

North-south alignment. Place few or no windows on the north wall, lots on the south wall.
Have overhangs on the south wall great enough to shade windows from midday summer sun.

Please utilize 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/

Horizontal Sheeting, Framing for Insulation, and Alternative Siding

Today the Pole Barn Guru answers questions about overlapping horizontal sheets of steel, the best plan for framing to insulate, and best way to install vinyl lap siding on a post frame building.

Horizontal Steel SidingDEAR POLE BARN GURU: When installing horizontal sheeting, does the top sheet always cover the bottom sheet when joined? GARY in EUFAULA

DEAR GARY: In order to prevent water infiltration, yes. Provided overlaps have sufficient overlap, gravity will pull water downward across this overlap.

 

DEAR POLE BARN GURU: I am looking to have a pole barn put up and wanted your opinion on how to best construct the shell if I want to insulate it down the road. From some of the things I have read I should include some type of foam board under the roof sections and maybe tyvek under the metal walls? Please let me know your thoughts. ROBERT in TIPP CITY

DEAR ROBERT: You do not want to place foam board between roof steel and roof framing as this will create a potential ‘slip’ between steel and framing, reducing or eliminating your roof’s diaphragm strength and resistance to wind loads.

 

DEAR POLE BARN GURU: I want to put vinyl siding on my pole shed. Do I need to frame 16″ on center walls between poles? What do you recommend? Thanks. TRAVIS in ANDOVER

DEAR TRAVIS: I would recommend using roll formed steel siding.

If your building is not yet erected, contact your engineer who designed your plans to have him or her confirm this is adequate. Place 2×6 wall girts bookshelf style between columns, with outside of girt and outside of columns flush. Install 2×4 Standard & better with wide face to wind at 24 inches on center vertically between pressure preservative treated splash plank and eave strut – nailing 2×4 to each girt with two 10d common nails. Toe nail at top and bottom.

Install 7/16 inch OSB or ½ inch CDX plywood to 2×4 per engineer’s recommendations. Wrap with a Weather Resistant Barrier and install vinyl siding.

 

 

 

Post Frame Homes Proliferate

Post Frame Homes Proliferate

Post frame homes have been a well-kept secret for decades. Well, not only is the bag the cat was in open, but the cat has also leaped out and is running rampantly!

Here at Hansen Pole Buildings, we have noticed a significant surge in requests for quotes, as well as general interest, in residential post frame construction. And, it isn’t just us who are noticing the trend.

Cindy Orschell is the executive director of the Franklin County (Indiana) Area Plan Commission and Building Department. When questioned about what is hot in building she reported, “The trend we are seeing a lot of are pole construction homes”.

There are many possible reasons for the increased interest, one of which is cost.  My brother wrote his thesis on the savings of post frame construction for Habitat for Humanity homes probably 30 years ago, so this is nothing new. It was seven years ago when I penned an article outlining the savings in foundation costs (which have only increased since): https://www.hansenpolebuildings.com/2011/10/buildings-why-not-stick-frame-construction/.

Virtually any stick frame building floor plan or elevation can be converted to a post frame building. For this reason, Hansen Pole Buildings does not offer choices for post frame homes on our website. See something you like? It can be done.

How much is it going to cost?

Hansen Pole Buildings GuesthouseThe structural system of a post-post frame home, its engineered plans and foundation are all going to prove to be less expensive than stick frame. Everything else is going to be pretty much the same – cabinets, fixtures and floor coverings do not suddenly become less expensive just because they were in a post frame building.

There is one place where you may end up spend a bit more up front than you might have with a stick built home – insulation and energy savings! Post frame buildings have fewer structural members which touch both interior and exterior surfaces, reducing the direct transfer of heat and cold. With deep wall cavities, more insulation can be added to the walls. Trusses with raised heels allow deeper insulation from wall-to-wall: https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/.

Where is the extra upfront investment? Paying for more insulation – which results in savings over the life of your home!

You can do it yourself!

Provided you can and will read the assembly instructions, tens of thousands of dollars can be saved by doing the work yourself. Post frame construction is extremely friendly to those who have the desire and inclination to self build.

Ready to build? We’re here to assist: sales@hansenpolebuildings.com

When the Pole Building Insulation Problem is Larger Than Imagined

When the Pole Building Insulation Problem is Larger Than Imagined

From questions I have received from loyal readers over the past year, post frame (pole) building insulation is right there at the top of the list for priorities. Sadly, it seems the same concern is not often put forward by those who are designing, providing and constructing post frame buildings – leaving far too many new building owners in a world of hurt.

DISCLAIMER: This is NOT a Hansen Pole Building

Reader KEVIN in WEST CHESTER writes: “When installing my insulation do I stop just short of the vented soffit inside at the top of the wall?”

Well, this is an easy question to answer – the wall insulation needs to not cover the air intake provided from the eave vents, if the thought is for them to be used as a functional vent.

Simple, wasn’t it?

Now we can get into the challenges presented in the photo.

Unless the walls are going to be insulated with closed cell spray foam, there should be a well-sealed building wrap between the wall framing and the wall steel. This allows any moisture which would be trapped in the wall to be able to pass through to the outside world.

Now, onto the big challenge – insulating the roof.

If the idea is to have the vents in the low eave soffit be an air intake, then there needs to be a corresponding air exhaust at the high end of the shed. Along with this there needs to be the ability of unobstructed airflow from the low eave to the high side above the roof insulation. This happens to be a Building Code requirement, not to mention it is designed to prevent mold, mildew and other associated decay issues. As the roof purlins appear to be an impediment to airflow if the cavity is filled – the solution may end up being to have to use closed cell spray insulation under the roof sheathing and do away with the eave ventilation.

Moral of the story – consider insulation and ventilation needs early on in the project, in the planning stages, not after the building shell is already constructed.

Attic Insulation Guide

Pole Barn Guru BlogWelcome 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: I am building a 24’x32′ pole barn type shop using 5 clerestory trusses in which I will install windows in the verticals for natural light. I want the roof shingled and insulated. Is there a way to frame in roof rafters between the trusses to carry the weight of the roof sheathing and to use batt insulation underneath? SCOTT IN ELLERSLIE

DEAR SCOTT: For sake of discussion, we will assume the trusses have been engineered to carry the weight of all of the materials you will be adding.

In order to use batt insulation as you propose, Code requires there to be at least a one inch air space between the top of the insulation (which must be unfaced) and the underside of the roof sheathing. This space must be vented at eaves and peak, and airflow must not be impeded.

Just off the top of my head (and knowing nothing about how your trusses are constructed), I’d probably look at placing a header at the eave and peak, which would carry 2×12 rafters placed every 24 inches and running the same direction as the trusses. Insulation batts up to 10-1/4 inches thick could then be placed between the rafters.

You should consult with the RDP (Registered Design Professional – architect or engineer) who designed your building, to confirm sizes and connections of members, as well as their adequacy to carry the imposed loads.

Mike the Pole Barn Guru

DEAR POLE BARN GURU: My name is Ben, and my husband and I plan to build a timber pole house in the mountains around Luray, VA. We are still in the planning stages, but are already working on the design stage of the house. I wanted to reach out and see if you offer the type of services we need, even though your website seems like you would be just perfect.

As a quick summary of our needs:

I am a 3d artist and am laying out the space in 3ds max to get an idea for room size, arrangement, and other proportions. However since I am not an architect, I need someone to go over the design, make it useable, point out any problem areas I am unaware of as a non-architect. Also being able to get all the materials cut and shipped to our building site is a huge plus.

Additionally, as we are still researching land, I would like input on what to look for based on our design, and then after land is procured, any adaptations needed for our plan to fit the space (the biggest thing I am worried about, is pile depth for the timber piles to pass code and be structurally sound). We plan on a 2 story building, so it’s likely the max timber height above ground would be around 35 feet for some of the timbers. We also plan to build on a mountain side, so the timber length would vary.

Is this the kind of service you can offer?

Thanks so much for your time,  BEN AND AGUST IN LURAY

DEAR BEN: We can supply columns up to 60′ in length, so you should not have any difficulties with what you have in mind – nor will needing various lengths be a challenge.

Our designs do not incorporate interior non-load bearing walls, as we have found room sizes tend to change greatly once the exterior shell is up and clients get a much better feel for what each room will do, as well as for orientation. Always try to work from the inside out – determine (at least close to) the area of the spaces you will need and then orient these spaces to be most functional for your lifestyle. Then create an envelope which fits around your spaces.

The ultimate location may (and should) play a great deal into the final design. Orientations should be such to take advantage of the most practical approaches to the site, as well as views and exterior living spaces (decks and patios).

Keep in mind – any pricing done now, is based upon where markets are at today. Lumber and steel are commodity items and prone to a great deal of variability which is beyond anyone’s control. Allow plenty of safety cushion in your budget, it is always a pleasant feeling to have more money left over, than having to scramble because things were planned too tight.

Mike the Pole Barn Guru

DEAR POLE BARN GURU: I am interested in pricing for a pole barn/apartment.  I am selling my house and will be purchasing roughly 15 acres of land.  I would like a pole barn constructed on the land.  I intend on building my own home which will take some time.  I would like a two story pole barn, with the upstairs being the finished apartment with somewhere around 900 square feet so I can live on my property while my house is being built.  Is this something that you would be able to do?  Thanks for your time. JEFF IN CINCINNATI

DEAR JEFF: Thank you very much for your interest in a new Hansen Pole Building. We provide post frame (pole barn) building kit packages similar to what you have in mind on a regular basis. You will be contacted shortly by one of our Building Designers to get more detailed information as to your exact needs.

Mike the Pole Barn Guru

TextraFINE® Post Frame Insulation

TextraFINE® Post Frame Insulation

It is nice to hear from those who have read and learned from the articles I have posted over the past nearly three years. Even more rewarding, is when Hansen Pole Buildings’ team members come up with products for me to investigate.

Just today Justine (the Hansen Pole Buildings ordering and delivery wizard) asked me if I was familiar with “Textra fine” insulation. She had stumbled upon it during a web search and was unfamiliar with it, having always used either fiberglass or cellulose products previously.

Putting on my aluminum pyramid-shaped research hat, I jumped upon my trusty stead Internet and went on a search.

Anco TextraFINE® Post Frame insulation has excellent mechanical, thermal and acoustical properties making it ideal for insulating post frame structures where wide rolls of un-faced insulation are required.

Textrafine InsulationTextraFINE® Post Frame insulation is made from inorganic silica sand which is formed into long textile-type glass fibers which are bonded together in random orientation by a stable thermosetting binder. This process produces unusually strong, resilient insulation which will return to full thickness following compression.

Manufactured with 85% post-industrial recycled content, TextraFINE® Post Frame Insulation can be a contributor to LEED® credits.

Standard sizes are six inches thick by 48” or 93” in width.

Basically the product (in its 93” width) is designed to friction fit between columns spaced every 8’. The idea being with 6×6 or 3 ply 2×6 laminated columns, and wall girts placed flat on the exterior of the posts, the six inch thick insulation will not extend inside the columns.

Before the International Building Codes were adopted, this would not have been a challenge, however to be Code conforming under the now enacted deflection criteria for wall girts – it IS a problem.

To find out more about deflection in wall girts: https://www.hansenpolebuildings.com/blog/2012/03/girts/

The structural framing solution, most often places framing in conflict with the installation of these wide insulation rolls.

TextraFINE® is also available as a Condensation Control Blanket (CCB) in standard one and two inch thick rolls. The average (or above average) installer or DIYer might want to think twice about this method of trying to control condensation by reading: https://www.hansenpolebuildings.com/blog/2011/11/metal-building-insulation-in-pole-buildings-part-i/

My take on TextraFINE® insulation? It is very probably a great insulation product, however the product as designed to be applied, may not always provide the best or most practical design solution.  As more jurisdictions become savvy to the new code, it would behoove companies such as TextraFINE® to produce insulation in a size conducive to fitting between girts. Also having a vapor barrier would afford it more advantages.

Rigid Insulation Boards Part II: Foam Board

 Yesterday’s blog featured a discussion of the various foam board products with application for your new pole building.  Used correctly, they provide good thermal resistance. Applied incorrectly can create a huge structural problem with pole buildings, along with safety issues.

Protect all types of foam  insulation from direct sunlight. Over time, the sun’s ultraviolet rays can damage the insulation. For roofs, this is generally done by applying a coating such as tar, acrylic, silicone, or rubberized paint. You can also cover the foam with a rubber or plastic membrane, or a layer of asphalt and roofing felt. Make certain you are using compatible products. The solvents in some coatings dissolve certain plastics.

In cold weather, warm inside air containing water vapor can get past the wall finish and insulation, condensing inside the colder wall cavity. In hot, humid climates the same thing can happen, just in the reverse direction. Humid outdoor air in the summer can condense inside cool, air conditioned wall cavities. If enough of this happens and the water cannot escape, wood rot, mold, and other moisture-related problems can occur. For this reason, building codes often require installing a vapor diffuser retarder on the warmest side of the wall cavity.

Foam board insulation is commonly placed against the steel building siding, between the girts of exterior walls. To prevent air infiltration, place rigid insulation boards tightly together and seal the seams with tape or caulk. This practice may worry some in cold climates since the foam board may act as a second vapor diffusion retarder. Studies have shown, condensation rarely occurs in these areas unless something else is seriously wrong with the wall assembly (like massive uncontrolled air leakage into the walls from the building). If the assembly is constructed correctly, the inside surface of the foam board stays warm enough to keep water vapor in its gaseous state long enough for it to escape.

When insulating a foundation you need to consider, although insects don’t eat foam board, they can easily tunnel through it. Insect burrows reduce the R-value and structural integrity of the insulation. For these reasons, some manufacturers treat their foam products with an insecticide, usually a borate compound. Many building jurisdictions also mandate treating the earth around the building with insecticides. These jurisdictions may also want an inspection area several inches wide and all around the foundation of a house kept bare of insulation board.

A better solution for below-grade walls in need of insulation is to install the foam board over the interior of the basement walls rather than on the exterior, which is more common. Interior applications prevent ground-dwelling insects from finding the foam board at all, and they eliminate the need for the bare inspection area. Insulating interior walls, however, requires careful attention to moisture control.

Most jurisdictions also require installing a fire barrier over the interior foam board. While this adds extra cost, the thermal performance of this method is superior in most cases to the more common exterior foam board application. This equates with a dollar savings in energy which can repay many times over for the additional cost of an interior application. If converting a basement into a living space, there is almost no additional cost.

Foam insulation is relatively hard to ignite, but when it is ignited, it burns readily and emits a dense smoke containing many toxic gases. The combustion characteristics of foam insulation products vary with the combustion temperatures, chemical formulation, and available air.

Because of these characteristics, foams used for construction require a covering as a fire barrier. One half-inch thick gypsum wallboard is one of the most common fire barriers. Some building codes, however, do not require an additional fire barrier for certain metal-faced, laminated foam products. Always check with local building code/fire officials and insurers for specific information on what is permitted.

While rigid insulation boards may afford a relatively high R-value, if installed improperly they can provide less than desired insulating results, structural issues or pose a fire hazard. In many instances, other methods of climate control may be more cost effective.