Insulating an uninsulated pole barn

[libbybrewer]

Hey fellas,

Seems like I've got a lot of time on my hands lately and I can start working on some of those projects that I never seem to find time to do. I've been doing a bunch of research, but can never really seem to find the answer for what I want to do. I was hoping if I put my situation up I could garner some conversation that might lead me to getting my project done.

I bought a house last year that has a big 30'x40' uninsulated pole barn, the ceiling is insulated though. Funny viewing of the house, the realtor took us there....the wife walked toward the house and I walked toward the pole barn, priorities I guess.

So my question is how do I insulate my pole barn without breaking the bank? I live in NW MT where we get cold and somewhat moist winters/spring (not PNW moist). I don't need the thing to be air tight, just something that will hold the heat while I screw around in there.

The current situation is sheet metal (on the outside) with 2x4s joisted horizontally between the 6x6 beams (on the inside). After pricing out foam boards, I quickly realized that its gonna cost me a fortune to get it insulated that route.

I thought maybe I could use fiberglass batt insulation and insulate the place piece meal as I find money to buy insulation, but keep getting hung up on these questions....
-Can I just stick fiberglass insulation between the 2x4s and then cover it up with OSB?
-Do I need to worry about condensation with mold and mildew between the sheet metal and batting?
-do I need to put some sort of Tyvek in between the sheet metal and batts?

Any input will help, I need something to keep me distracted between telework and teaching my kids school while schools are shut down. Thanks in advance folks

 

[wingrider02]

Do you want the walls covered, or just insulated? There are insulation blankets that are used in pole barns to hang like curtains in between the poles. If the shed doesn’t have a vapor barrier on the steel side of the building, it is my understanding you can put plastic over the insulation.

If you want to cover the walls, then you need to put in some more lumber to span the posts. I chose to do bookshelf girts in my shed.

 

[ard]

IM you NEED stuff to be airtight....or you will wind up with warm, moist air moving into the walls and condensing. Leading to mold and rot.

I’d want a breathable membrane against the metal, to allow moisture and air out but prevent water entry. Then on the inside an impermeable layer to prevent air and moisture from moving into the wall. NOT osb alone. Plastic under the OSB, or Sheetrock/tape/paint as a finished layer.

Will you be heating the interior?

 

[libbybrewer]

I never heard of the horizontal stud work being called bookshelf girts, that gives me some things to research into.....thanks. How did you insulate your shed? did you use a tyvek layer between the outside and the insulation? did you just use fiberglass batting unrolled horizontally between the girts?

 

[libbybrewer]

IM you NEED stuff to be airtight....or you will wind up with warm, moist air moving into the walls and condensing. Leading to mold and rot.

I’d want a breathable membrane against the metal, to allow moisture and air out but prevent water entry. Then on the inside an impermeable layer to prevent air and moisture from moving into the wall. NOT osb alone. Plastic under the OSB, or Sheetrock/tape/paint as a finished layer.

Will you be heating the interior?

________________________
Thanks, I plan on putting a wood or pellet stove in there to heat it up the 2-3 a week I will be in there. I was hoping to get away without needing any membrane between the metal and the insulation....that is gonna be a pain in the ****. I see the need for it though. Thanks

 

[Dragfluid]

Rather than retyping a lot of info, just take a peak at my build thread. Lots of good info in there for what you're doing.

 

[fourbyford]

I used 1 1/2" foam between the girts and covered with OSB which has resulted in a pretty airtight and solid structure. Although the foam may seem expensive, I didn't need a vapor barrier or house wrap, which saves time and money.
As dragfluid mentioned, lots of info in my thread as well including thoughts on mold, etc. And, I'm in northern Idaho, although we're more of the PNW weather than you probably are. If you choose to go with the foam, it goes pretty quickly... I found the blue stuff (Dow) cuts the best. I had to order mine through HD but, it came in in just a few days and was actually less expensive than the pink stuff (O/C). I made all the cuts I could on the table saw... HTH

...D

 

[Azzkker]

My pole barn was not insulated when I bought my house. I used new factory rejected Dow thermax board. 1.5" between the horizontal 2 x 12", to match the thickness of the 2x12, the bookshelved 3" on that. Then used expanding foam around each piece to seal it up. The 3" overlapped the 1.5" for proper seal and the double foil faced acts as the vapor barrier when properly sealed. Covered with white metal panels from Menards.

The 1.5" was 10 bucks a sheet, the 3" was 15 a 4x8 sheet. Look on craigslist for a vender selling reclaimed and rejected pieces. The rejected pieces are mostly just a small Nick in the insulation, or a minor error in thickness. I bought enough for my building for around 1500 delivered. Saved thousands of dollars doing it that way and its super cheap to heat.

 

[theoldwizard1]

Not low cost, but the best thing to do is hire some one to install 2" of closed cell spray foam. It will seal up all of the cracks and even where the screw come through. Then you can add as much fiberglass as you want.

If budget is a real issue, do just the ceiling, but you will regret not doing the whole thing.

(P.S. DIY spray foam, especially on a large job, is not worth the hassle !)

 

[Natty Bumppo]

I insulated my 25x35 pole barn with 2" polyiso that I found on CL and FB. Not sure about your area, but around here there are many guys who sell 2nd's and reclaimed insulation of all types. The price is generally half of the cost of a new sheet from a box store. I found all brand new sheets of 4x8x2" polyiso for about $15 a sheet. I used Tyvek against my exterior sheathing and cut the pieces of polyiso to fit. Studded out the spaces between the walls, ran wires, and then I covered that with my interior wall covering.

 

[libbybrewer]

I used 1 1/2" foam between the girts and covered with OSB which has resulted in a pretty airtight and solid structure. Although the foam may seem expensive, I didn't need a vapor barrier or house wrap, which saves time and money.
As dragfluid mentioned, lots of info in my thread as well including thoughts on mold, etc. And, I'm in northern Idaho, although we're more of the PNW weather than you probably are. If you choose to go with the foam, it goes pretty quickly... I found the blue stuff (Dow) cuts the best. I had to order mine through HD but, it came in in just a few days and was actually less expensive than the pink stuff (O/C). I made all the cuts I could on the table saw... HTH

...D

That's the type of info I've been looking for. I probably have a more similar climate than you. I live in Libby where we get a fairbit of that PNW weather. I read through some of your blog, a lot to digest there, I think I read all of the insulation information.

From what I read you went with sheet metal, 1.5" of foam and then OSB (outside in)? Is that all the insulation you used? From what I gather the pole barn is used mostly for housing vehicles, but does that much insulation keep it warm enough where if you heat the place it doesn't need constant heat and is fairly warm?

 

[stm317]

There are two ways that a building feels cool.
First is temperature. You combat this with the highest R value that you can afford.
Second is air movement. You combat this with something impermeable like Foam.

If fiberglass insulation has an R value of R19, but air can easily move through it, it's going to feel like a much lower R value. If no air moves through it, then you feel the full R value of the insulation.

Foam is going to give you a bunch of r value per inch of thickness, and it's going to stop any air movement at the same time, so in my opinion it's worth the upfront cost. Because it does both at the same time, you can get the same performance with less too. So for example, R10 foam panels will probably feel like R19 fiberglass, maybe even feel better than the fiberglass with the higher R value. And foam handles moisture better than fiberglass does too.

Spray foam was out of budget for me, but I did 1.5" foam panels in between my girts and it really made the building more comfortable right away. I've added R19 fiberglass inside the foam as time and budget have allowed. The foam does the bulk of the work on the outside and the fiberglass is just gravy. Check local for sale sites for used/reclaimed/seconds of the rigid foam. I got mine that had never been installed for about 60% of what it sells for at the big box store.

 

[kylefitz]

There are two ways that a building feels cool.
First is temperature. You combat this with the highest R value that you can afford.
Second is air movement. You combat this with something impermeable like Foam.

If fiberglass insulation has an R value of R19, but air can easily move through it, it's going to feel like a much lower R value. If no air moves through it, then you feel the full R value of the insulation.

Foam is going to give you a bunch of r value per inch of thickness, and it's going to stop any air movement at the same time, so in my opinion it's worth the upfront cost. Because it does both at the same time, you can get the same performance with less too. So for example, R10 foam panels will probably feel like R19 fiberglass, maybe even feel better than the fiberglass with the higher R value. And foam handles moisture better than fiberglass does too.

Spray foam was out of budget for me, but I did 1.5" foam panels in between my girts and it really made the building more comfortable right away. I've added R19 fiberglass inside the foam as time and budget have allowed. The foam does the bulk of the work on the outside and the fiberglass is just gravy. Check local for sale sites for used/reclaimed/seconds of the rigid foam. I got mine that had never been installed for about 60% of what it sells for at the big box store.

Did you do expanding spray foam between the girts and the foam panels?

 

[Black Oak]

Did you do expanding spray foam between the girts and the foam panels?

Home depot sells a DIY foam spray kit , I believe is $39- only covers about 20 sq. ft. or so . Comes in a small box . Enough to seal the four corners and maybe a door or window . If you fit your foam panels between the girts tight , you'll be surprised . Air infiltration is the worst thing about a pole barn . I used a table saw to rip foam panels , as tight as I could get them .

 

[fourbyford]

Hey L.B.

I initially went with a single layer of 1 1/2" foam covered with OSB inside the building and saw a noticeable difference. The R value of the foam is 7.5. I decided to upgrade my doors (but haven't done it yet)... the ones I will install as soon as the budget allows are R 18.5 and each panel has thermal breaks. Nice doors. So... I thought it didn't make a lot of sense to have R 18.5 doors with R 7.5 walls. So, I began going around the shop (30 x 36), removing the OSB, and installing additional girts and adding a second layer of insulation. (details in my thread) Now, my walls are theoretically R 15 and, while I was at it, I upgraded my electrical and added air lines... all enclosed in the walls. I recently installed an 80k btu Mr Heater, ceiling mounted, and the garage is awesome! (I also added insulation to my single sided doors) I keep the garage at about 48°... if I'm working out there and get a bit chilly, I just move the thermostat to about 54° and, in a few minutes, it's T shirt weather!
The only insulation in the ceiling is the white vinyl encapsulated fiberglass, commonly used in pole buildings. Hopefully, this coming fall, I'll re-work the roof and add insulation in the ceiling. But, I've been heating for almost 2 months now and, as I mentioned, the garage is comfortable and it hasn't cost a fortune to keep it that way.
I was through Libby a few years back... that right there is God's country!

Let me know if you need more info.

...D

 

[fourbyford]

RE: fitting foam panels...

I cut mine on the table saw for the tightest friction fit I could achieve. Once the foam was installed, between that and the OSB, I couldn't feel ANY air infiltration. Resistance to air infiltration and moisture resistance were the two reasons I went with foam.

...D

 

[stm317]

Did you do expanding spray foam between the girts and the foam panels?

I did not. Fully sealed foam would be a vapor barrier which I wasn't comfortable with on the outside of my walls. I wanted them to be able to vent to the outside somewhat rather than trapping moisture in the framing/insulation where mold can form.

I also ran my electrical before installing my foam, with most of the wiring running along the tops of the girts. So, I cut my foam with the table saw to fit pretty tightly everywhere except the bottom where I left a gap about 3/4" where the wiring ran. That gap was convenient for the wiring, but also keeps the foam from becoming a true vapor barrier too.

 

[libbybrewer]

Just wanted to thank the folks for giving me their input...I was able to figure out a path forward after reading all of your experiences. Thanks

 

[Pressingonward]

Just wanted to thank the folks for giving me their input...I was able to figure out a path forward after reading all of your experiences. Thanks

Please post up a couple of in-process and completed pics as well as your thoughts after doing it...always good to see which direction people choose and what the results are. I need to get mine insulated someday

 

[Buck41]

I used lumber wrap. Up about 4 feet stapled to the top plate and roof joists Lumber wrap was free at the lumber yard. I put R49 blow in Insulation.

 

[Bigshow0003]

New poster to the forum here, but have been a reader for the last couple years. I have a 30x40x10 in northern WI, not far from the UP MI. Built in 2018, but I am finishing the inside of my building now. My builder offers inside finishes too, but my rep told me to just do it myself since its so easy. He told me to buy a case of Great Stuff spray foam and apply it behind the 4 corner posts; and to also lay a bead atop the bottom exterior girt and atop the girt that separates the wainscoting. He said those three places will be my biggest air gaps. Seal those off and I'll be good.

After that I'm doing studs on 24" centers, faced R19 batts, 4x10 7/16 OSB walls, and a steel rib ceiling. Although I haven't quite decided on what to do for insulation up there yet. I have a quote from a spray foamer to do the bottom of roof deck. Although that's quite expensive vs doing blown or batts myself, the sprayed roof deck would ensure no issues of condensation.