Insulating and Sheeting Interior of a Pole Barn
STEVE in EDEN writes:
“We have four seasons with temps getting below freezing in the winter and up to 90 in the summer, with average humidity of 70% and 20%, respectively. I have a pole barn with metal skin. The ceiling or inside of roof is insulated with plastic coated insulation. The walls are not insulated. The 2×6 Girts were installed between the poles with their flat sides parallel to the floor. In other words, the 6 inch width of the board is horizontal or laid flat. I wish to insulate and sheet the interior of the barn. I anticipate heating the interior only when in use to about 50 degrees and may run a standing shop evaporative cooler or even AC in the summer during the hottest times to about 80 degrees. The structure is 32 x 50 x 14, has two insulated garage doors at one end, two man doors and two 4×2 windows. I’m on a budget. I plan to sheet the interior walls with 1/2 inch OSB. I have a few questions: 1. Should I use vapor barrier between insulation and OSB? Insulation contractor who lives down the street claims it’s unnecessary in our climate and given my use, but I wonder. I am going to paint the OSB. Perhaps that will act as a barrier? 2. The Girts are on about 32 inch horizontal centers. I plan to install the OSB board vertically, or rather on their ends, but am open to staking them horizontally. Any advice there?3. If I install vertically, should I frame in studs such that the vertical or long sides meet on a stud? I will run a base plate along the concrete floor, so the weight of the OSB sheeting will be supported on that plate. I’m just looking to cover the insulation. I’m not going to be hanging anything on the walls. I have metal, standalone shelves and cabinets for storage. I really appreciate your help here. I am DIY’er for sure. I have to do this stuff on my own.”

As roughly 3/4 of all heat loss is up, and you are on a budget, you may want to investigate adding a ceiling to underside of roof trusses first. Provided roof trusses are adequately designed to support a ceiling load, and adequate ventilation is provided for at eaves and ridge, this would allow fiberglass insulation to be blown in above ceiling finish.
Your building’s roof Metal Building Insulation provides very little resistance to heat loss, as fiberglass above vinyl facing is crushed down to nothing every time a roof purlin is crossed.
On to answers to your questions:
1) I recommend using Rockwool insulation (as it is unaffected by moisture) with an interior vapor barrier. Not having a Weather Resistant Barrier between wall framing and steel siding, you may experience some condensation on interior of siding.
This can usually be mitigated by mechanically dehumidifying when relative humidity inside building is high and exterior temperatures are low. 2) and
3) While 5/8″ Type X gypsum wallboard is less expensive and provides fire resistance, for either it or OSB I would run vertically. Usually blocking those vertical seams is unnecessary, however you could run 2×4 blocking between girts at seams, if desired.





DEAR POLE BARN GURU: What is practical priced good ceiling fan for a post frame 36 x 60 work shop, I plan on installing two. What height is good for a Modine hotdawg hanging natural gas heater with building with 14 ft walls? SCOTT in WISCONSIN RAPIDS
DEAR POLE BARN GURU: We have a pole barn it was purposely built to have an apartment upstairs; it originally was a stable below. It’s all living quarters now. We have had issues with the steel roof. We are switching to class 4 shingles. The building has no eaves as it has porches off both sides. We are working with a roofer. They are suggesting we use some ridged vent at the lower edge of the roof, by cutting a notch in the edge and installing it under the shingles and decking. That’s my understanding. Also, it will have a full ridge vent. The steel was applied on decking with tar paper under it. We have had leaking and condensation with it, as it is. Just wondering if you have any other ideas, or if the ridged vent at the lower edge of the roof will be a problem? It has 16″ deep trusses with blown in insulations above the sheet rock ceiling. Thanks for any input or ideas. JENNENE in RAPID CITY
DEAR JUSTIN: In most instances a reflective radiant barrier is a waste of your hard- earned dollars. They can be (when properly sealed) an excellent vapor barrier, however using a perforated product takes away even this as a possible benefit. Walls – from out to in…. Siding, Omnidirectional housewrap over bookshelf wall girts, fill entire cavity with Rockwool insulation batts, well-sealed clear poly vapor barrier, interior finish. Roof – Order raised heel trusses (at least an inch taller heel than depth of blown in fiberglass (not cellulose) insulation). Order roof steel with an Integral Condensation Control factory applied. Vent eaves and ridge in correct proportions. No ceiling vapor barrier.
DEAR POLE BARN GURU: I have an existing pole barn on property that I would like to insulate. I would like to steer away from spray foam but am worried as there is no Tyvek or vapor barrier on external side. What are my best options to void off any moisture issues and create a well insulated wall. JAMES in LAKE VILLAGE 

DEAR ROBERT: All of these recommendations are based upon meeting energy code requirements for conditioned buildings. Washington State will be a stickler for these.
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
“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 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).
DEAR POLE BARN GURU: When installing horizontal sheeting, does the top sheet always cover the bottom sheet when joined? GARY in EUFAULA
DEAR POLE BARN GURU: 
The 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.
DISCLAIMER: This is NOT a Hansen Pole Building
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.
TextraFINE® 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.
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.