Insulating a pole barn for a/c

[ATCGA]

Hi All,

Ready to start the building process of my 30x50x12 enclosed pole barn on a slab. Steel trusses with purlins for the roof and wooden girts for walls. I would say typical pole barn construction. All metal roof and sides located in south Alabama. I’ll definitely need more cooling than heating.

My question is regarding proper insulation. Could you tell me what the preferred method of insulation would be given that I want to heat and cool the building? I want to get it right before I start building.

Thanks in advance.

 

[mrpizza]

Spray 2” of closed cell spray foam roof and walls. You will be good. Or do a mixed system of 5” open cell on the roof and closed on the walls. Unless you will finish interior walls, then 5” open cell all around. Thats how i did my house

 

[ATCGA]

Spray 2” of closed cell spray foam roof and walls. You will be good. Or do a mixed system of 5” open cell on the roof and closed on the walls. Unless you will finish interior walls, then 5” open cell all around. Thats how i did my house

Thanks. I’m definitely considering foam. The ceiling with the joists will be exposed but I plan to finish the walls with an osb wainscot and metal above.

 

[ATCGA]

Spray 2” of closed cell spray foam roof and walls. You will be good. Or do a mixed system of 5” open cell on the roof and closed on the walls. Unless you will finish interior walls, then 5” open cell all around. Thats how i did my house

So 2” of cc foam will give me about R14 on the ceiling. Will that be enough to block the heat on those 100 degree days?

 

[bobbyjean]

so....if ceiling is exposed...you have no vented soffit or ridgevent i guess? will you just spray foam directly to roof? sounds like a big space saver if you could do it that way

 

[ATCGA]

so....if ceiling is exposed...you have no vented soffit or ridgevent i guess? will you just spray foam directly to roof? sounds like a big space saver if you could do it that way

Yes, I’ll spray directly to the roof. No need for soffit or ridge vents if that’s done.

 

[DC73]

So 2” of cc foam will give me about R14 on the ceiling. Will that be enough to block the heat on those 100 degree days?

It'll help but isn't near enough. I'd want a minimum of 5" if it was my building.

DC

 

[stm317]

Foam and moisture don't typically go well together do they? Id imagine humidity is a concern in AL. I'd add a moisture barrier like some Tyvek/house wrap between the girts and the metal. Probably a good idea to do something for the roof too. Double bubble radiant barrier is what is typically used way up here. Not sure if that would work down there or not.

I don't even want to think about what it might cost to do foam several inches thick in a building that size, but it is nice stuff if you can afford to go that route.

 

[theoldwizard1]

Spray 2” of closed cell spray foam roof and walls. You will be good.

That us a good start. You might need more later.

 

[ATCGA]

Thanks everyone. This topic is a little more complicated than I thought it would be. Pretty straight forward on a typical stick built garage. Metal seems to complicate things.

 

[rburke65]

TACGA......NO one here knows where you live...that might help a lot since you're talking heating and cooling......

 

[ATCGA]

TACGA......NO one here knows where you live...that might help a lot since you're talking heating and cooling......

In my original post I say South Alabama.

 

[semi75]

I agree with Miles, 2 inches of closed cell foam should do wonders for you with an air conditioner. I saw it mentioned by few that you might want more that 2" of closed cell and even saw 5 inches of closed cell mentioned...... holy frig who is paying for that? The other commit was against humidity and foam. If you have closed cell foam in a metal building and an ac you are cooling and dehumidifying so there isn't a problem, especially with closed cell.

The one thing I will mention is if you don't wish to cover the foam then rent or buy a sprayer and paint it with an acrylic latex so UV light doesn't compromise it. I have done it both ways, covered the walls with tongue and groove and put a metal ceiling in and just painted it in another building.

 

[ATCGA]

I agree with Miles, 2 inches of closed cell foam should do wonders for you with an air conditioner. I saw it mentioned by few that you might want more that 2" of closed cell and even saw 5 inches of closed cell mentioned...... holy frig who is paying for that? The other commit was against humidity and foam. If you have closed cell foam in a metal building and an ac you are cooling and dehumidifying so there isn't a problem, especially with closed cell.

The one thing I will mention is if you don't wish to cover the foam then rent or buy a sprayer and paint it with an acrylic latex so UV light doesn't compromise it. I have done it both ways, covered the walls with tongue and groove and put a metal ceiling in and just painted it in another building.

Thanks. Great advice. Never thought of the idea of painting over the foam.

 

[skippydoo]

Thanks. Great advice. Never thought of the idea of painting over the foam.

Will the paint hold up over time?

 

[norson]

I have a 36' x 48' x 14' side walls steel framed with 6" purlins on edge. When it was built they installed a 2" blanket. Since then I've added 6" fiberglass bats to the walls and finished it with CDX. I will add 6" bats to the ceiling in the coming year. I have a two ton airconditioner and when it is 92 outside I can maintain it at 69 degrees. In the winter when it is 20 degrees outside it is 40 degrees inside with out heating. I do have a wood stove, but haven't used it enough to give a good figure. I find I can work fine at 45 to 70 degrees. I think when I get the ceiling done it will take less money to maintain a comfort level.
Norm