Building a shop/oversized garage. We have a quote for closed cell spray foam 1" thick.

What thickness for shop walls/roof would you guys suggest? Will 1" really do much or should I shoot for 2, 3, or 4"s?

I did 1.5" on the walls, 2" on the ceiling. Closed cell.

ag0207 said:

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Building a shop/oversized garage. We have a quote for closed cell spray foam 1" thick.

What thickness for shop walls/roof would you guys suggest? Will 1" really do much or should I shoot for 2, 3, or 4"s?

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It would also depend on your location.
You would need more in Fairbanks than south Texas.

1.5" closed cell on walls and 2" closed cell on roof is typical. Ask whomever prices it for you if they can put dye in the insulation. It's cheap and looks good.

Spray foam is doing more than insulation. That closed cell foam is also provided an air seal and a vapor barrier. The r value is not the only important part. If I was heating or cooling the shop, I might want more. I do see why they are going with 1" though. I am not sure how helpful this is, but I wanted to point out that the foam is there for multiple reasons. Also, the R value of 1" of closed cell is 6.5-7, so two inches would give you R-13.

I just have the wrap for my shop, think it is around R4 or R5. Event hat little bit makes a noticeable difference in the temps during the summer time. It also helps create a draft when I open the main doors on the north and south side so I usually get a good breeze through the shop.

I did 1.5" closed cell for the first 8' of my walls and about 4" of open cell on the rest of the walls and ceiling. I painted it all white for the reflective property. Been 2 years and I'm happy with it so far.

Thanks for the responses. I just want it to keep it down a few degrees in the summertime and didn't know how beneficial 1" would be.

ag0207 said:

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Thanks for the responses. I just want it to keep it down a few degrees in the summertime and didn't know how beneficial 1" would be.

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So tempting to go for the punchline there...

In my previous shop I had the "roll" insulation that is just fiberglass insulation on a roll with a vinyl backing. It is about an inch thick and I can tell you without question, that still makes a huge difference! I work on a ranch that has two near identical metal buildings. One is insulated with the roll insulation and the other not at all and they are dramatically different in both winter and summer. It is absolutely significant and worth it.

I think for my metal building (shop + barndo), I did 1.5" on the walls and 2" on the ceilings. Closed cell.