Pole barn insulation questions

[Bradbilt]

Hey guys. Getting closer to putting up the building
40x96 and 40x 66 will be finished(insulated walls and ceiling)
There will be. 40x16 bay that will be dedicated wash bay/spray booth.

Ok, now for the insulation question.
I was thinking about spray foam for the walls, but it is only an R6 per inch thick. So I would need almost 4” and that would cost me about $10k
I am told the spray foam will keep the outer Tin from sweating And it makes an airtight seal

The fiberglass insulation is an R21 and would cost about $4k. But will the fiberglass soak up the moisture off the outer Tim when the building sweats? Should a tyvek wrap be used before the outer tin goes on?

The ceiling will get tin as well and blow in insulation to s R38


Ok. Fire away with your thoughts

 

[6768rogues]

I would spray an inch of foam on if you are worried about condensation and to block drafts, then use conventional fiberglass insulation inside of that. If the foam is still too expensive, use fiberglass without the foam. If you have girts under the steel, there should be an airspace where the insulation will not be touching the steel. Also, with insulation in the cavity, there will not be hot air inside against the cold steel, causing condensation, so condensation will be minimal if any at all.
You described a 96 foot long building 40 feet wide with one 66 foot bay and one 16 foot bay. I cannot help but wonder about the remaining 14 feet.

 

[Bradbilt]

I would spray an inch of foam on if you are worried about condensation and to block drafts, then use conventional fiberglass insulation inside of that. If the foam is still too expensive, use fiberglass without the foam. If you have girts under the steel, there should be an airspace where the insulation will not be touching the steel. Also, with insulation in the cavity, there will not be hot air inside against the cold steel, causing condensation, so condensation will be minimal if any at all.
You described a 96 foot long building 40 feet wide with one 66 foot bay and one 16 foot bay. I cannot help but wonder about the remaining 14 feet.

Girt? is that like a purlin? Strips of wood screwed to the pole to fasten the tin.

I was toying with the idea of 1" of spray foam + the r21 fiberglass batts. Air tight and high R value

The building would be 96 total length. a 16' spray booth/wash bay, 50' of work shop(2 bays and a "work area"), and the remaining 30' would be just storage.

 

[rburke65]

Girts and purlins are two different things.

 

[Bradbilt]

Girts and purlins are two different things.

Please educate me. What is a Girt?

 

[Skunkape]

By no means am I an expert, but it just wasn't in my budget for spray foam insulation on my post frame. I opted for the 2" vinyl backed insulation over the double bubble.. Don't get me to lyin', but I think it's like an R-6, R-10... not much at all. however, they layed it over, then screwed the sheet metal to it. I haven't experienced any moisture issues on the insulation.. However, I think the roof vents have made a huge difference. It's still chilly in the winter, and suprisingly cooler in the summer.[img]https://i.imgur.com/tvwVArO.jpg[/img]

 

[NitroGarage]

Please educate me. What is a Girt?

Purlins go across the trusses or between, girts are on walls and go across the posts or between.

 

[Bradbilt]

Purlins go across the trusses or between, girts are on walls and go across the posts or between.

Ok, Thanks. The same thing as a purlin, just on the walls

 

[stm317]

Definitely have the framing wrapped in Tyvek before the metal goes on. Yes, condensation will drip from the metal into your insulation. That's especially bad if you're doing cellulose in the ceiling as it will hold the moisture for a long time. Some builders will use double bubble on the roof rather than Tyvek. Not sure if one is really any better than the other.

If you're not happy with the fiberglass or cellulose options, and spray foam isn't in the budget there's always the option of rigid foam panels. I put 1 1/2" thick polyiso foam ( the same stuff as spray foam) in between my girts. They fill the gap between the framing and the metal perfectly, and do a much better job of killing air movement than fiberglass does. Because it's the same thickness as my framing, I still have a full 5.5 inch cavity that can be framed and insulated with fiberglass for the bulk of my R value too. If you check craigslist, you might be able to find places that sell rigid foam for quite a bit less than the box stores. I think I paid $16/sheet vs $25 @ the local Big Box. That's under half what it would've cost to have that amount of board feet spray foamed.