Thanks for all the info. We will have some perimeter insulation around the portion of the barn that will be turned into a studio area. I think I'll just lay th 6 mil stuff- as I can get that easily and it's inexpensive.
Vapor Retarder Under Slab?
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mjarrels
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I had a garage on Whidbey Island that was vented on each end and the floor would sweat like crazy each winter... have a garage in Virginia not vented and never have issues with the floor.
mark
mark
I agree, put down some poly and insulation. It's real easy to put insulation down before you pour but sort of a wee bit more difficult afterwards.
If you only put down the insulation where the studio is, the rest of the floor will sweat and get slicker than deer guts on a door knob. You will also have problems with dampness in the whole building and possibly mold from the damp. Is this a short time budget job or a long term deal? You will kick yourself for many years if you don't insulate...
jb
If you only put down the insulation where the studio is, the rest of the floor will sweat and get slicker than deer guts on a door knob. You will also have problems with dampness in the whole building and possibly mold from the damp. Is this a short time budget job or a long term deal? You will kick yourself for many years if you don't insulate...
jb
mudcat
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Carefull, you might want to state that you will be using your tractor to put the poly down. Or else the project police will move your thread!
AndyM
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mudcat said:Carefull, you might want to state that you will be using your tractor to put the poly down. Or else the project police will move your thread!
I think he wears a plastic badge while he's sitting at his computer.
neilly2
Silver Member
If you are concerned about slab curling, but an extra roll of poly, 4 mil will do, and cover the concrete with it as soon as you are done finishing and leave it for 7 days. This will retain moisture on the top surface which will prevent differential curing between the top and bottom (the cause of curling). At seven day strength the concrete will be of sufficient strength. This is ACI accepted for proper curing. But by all means put the vapor barrier in.
That said, I've installed millions of square foot of slab on grade without curling or installing the poly on top, but if you're worried that's a correct way of doing it.
A 4" slab is fine if the subgrade is compacted to 95%. But I don't know many small residential guys that do that, or even know how to do it. That said I would cover my bases and pour 5'' with a rebar mat (#3s), to allow for inadequate subgrade. This should be a much bigger worry for you than slab curling.
Also, whoever is pouring 12" slabs for pole barns is wasting a lot of concrete.
That said, I've installed millions of square foot of slab on grade without curling or installing the poly on top, but if you're worried that's a correct way of doing it.
A 4" slab is fine if the subgrade is compacted to 95%. But I don't know many small residential guys that do that, or even know how to do it. That said I would cover my bases and pour 5'' with a rebar mat (#3s), to allow for inadequate subgrade. This should be a much bigger worry for you than slab curling.
Also, whoever is pouring 12" slabs for pole barns is wasting a lot of concrete.
