Wanting to add a/c & heat to shop -- suggestions?

I'm getting a few more nice tools and I want to insulate and add a/c & heat to my shop. It's a pole barn style shop with a concrete floor. The entire building is 30x40 but my shop is the back half so 20x30.

I'm going to use an 18k btu mini-split unit to provide the comfort. My question is on the insulation. I know I'll be putting sheetrock up and R30 batts inthe ceiling. The question is the walls.

I can either insulate inside the existing walls (up against the metal) or I can stud up a 2x4 wall just inside the outside wall (screwing it to the concrete at the bottom and nailing it to the trusses above). I would be giving up a tiny bit of space but the wall could take more than a R13 batt and would be a regular stud wall which is easier to sheetrock.

Ideas?

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Originally Posted by Reggie Burnett

I can stud up a 2x4 just insnide the outside wall (screwing it to the concrete at the bottom and nailing it to the trusses above). I would be giving up a tiny bit of space but the wall could take more than a R13 batt and would be a regular stud wall which is easier to sheetrock.

Ideas?

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Reggie,

I built a tackroom for my wife in the metal barn about 8 years ago and this is what I did. She lost some space, but it solved a number of issues (condensation on from the metal on the insulation, etc) and made construction so much easier. I would highly recommend it

Consider the floor, also. That concrete is a lot of thermal mass and a potential source of water vapor. Depending on your climes and cost of energy you may be dollars and comfort ahead when you start conditioning the air by addressing that issue now.

I'd definitely go with the stud wall. You'll thank yourself every time you need to hang something up.

Don't know where you are, but if you're in the frozen north you pretty much can't have too much insulation. R56 in the ceiling and r24-30 walls are quickly becoming the norm here. If you decide to put down a more comfortable floor I'd certainly add 2-4" of rigid foam underneath, assuming your slab wasn't insulated when it was poured. You'll be surprised how much more comfortable it is.

I was in this same boat not too long ago. I build a pole barn, with 1200 sf living quarters and 1100 sf shop. I started by snapping a line on the floor which ensured any variation from the posts in the ground wouldn't give me a wave in the wall. Then treated base plates between the posts, framed in walls between posts with standard 16" studs starting at the corner just like a normal wall and just skipping any studs that fell on a post. I insulated this area with R-19 batt insulation then sheeted it with 1/2" plywood. The remaining 6' to the ceiling, I hung fabric for the blown in insulation and hung girts on 3' centers to fasten liner panel. The ceiling has 12" insulation and liner panel. The outside of the barn is wrapped with house wrap so I didn't have to worry about condensation.

Yes it was time consuming to frame between the posts but it allowed me to work in stages and I didn't lose any real estate. Here's a couple pictures from when I was in different stages of building and now that it's done.

Attachment 411891

Attachment 411892

Attachment 411890

Consider putting purlins on the inside of the posts. You can then insulate with the batts of your choice, running horizontally. It saves a fair amount of lumber and makes insulating easy.

Natural gas is the cheapest heat in North America in case you live here.... Why do you think you need heat or AC? What is your climate? A location might help use plan for you. If you need AC I doubt you are in Alaska or Siberia.
Bill D

I did fiberglass between the studs, and then a layer of 1" XPS on top. That way there is no thermal bridging bringing down the rest of the insulation.

I'm not sure, but I think the metal sheet might be a source of condensation. If that's the case I'd insulation like a concrete basement wall, which is to say some sort of closed cell foam up against it. This will seal out moisture which can ruin your insulation, and then the sheetrock. You can either put XPS foam insulation sheets up against the metal, or spray and inch or two of spray foam on the wall between the studs.

Oh, and you can order spray foam online, and save some money over paying a contractor. Seemed relatively easy to do, if a bit miserable since you're in a bunny suit, and the temperature needs to be between 65-85 degrees. I've done the roof of both my house, and also my garage this way. Once I had done 2" in the garage I was seeing a 5-10 degree swing between the outside temps, and the internals, and this was with no insulation on the walls.

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Originally Posted by Andrew More

I did fiberglass between the studs, and then a layer of 1" XPS on top. That way there is no thermal bridging bringing down the rest of the insulation.

I'm not sure, but I think the metal sheet might be a source of condensation. If that's the case I'd insulation like a concrete basement wall, which is to say some sort of closed cell foam up against it. This will seal out moisture which can ruin your insulation, and then the sheetrock. You can either put XPS foam insulation sheets up against the metal, or spray and inch or two of spray foam on the wall between the studs.

Oh, and you can order spray foam online, and save some money over paying a contractor. Seemed relatively easy to do, if a bit miserable since you're in a bunny suit, and the temperature needs to be between 65-85 degrees. I've done the roof of both my house, and also my garage this way. Once I had done 2" in the garage I was seeing a 5-10 degree swing between the outside temps, and the internals, and this was with no insulation on the walls.

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When I was designing my shop I asked the local metal supplier if I could spray closed cell directly on the inside of the metal, they reported that doing so would violate the warranty on the paint.

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Originally Posted by Jeff Bartley

When I was designing my shop I asked the local metal supplier if I could spray closed cell directly on the inside of the metal, they reported that doing so would violate the warranty on the paint.

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That's a new one. Did they say why? I can understand to some extent it's going to ruin the paint on the sprayed side, in that it's impossible to get off the foam without also removing the paint, but I don't know why you would do so.

It's a pretty common suggestion to spray foam a metal building. Now it can be problematic with closed cell to spray a roof, because it there's a leak, it won't leak through the closed cell foam so you can easily see it, but then again, you should be replacing a roof before that happens.