Vapor barrier or not, you'll get condensation on the surface if the slab is cold and the weather is warm and humid. By your description, today's conditions were perfect for a sweating slab.
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19 years ago
Sweating Concrete
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- posted
19 years ago
I had a slab (30' x 32') poured with a vapor barrier last January. Since then I have built a metal building for a workshop on it. Today I noticed that the slab was sweating and it was my impression that the vapor barrier is suppose to deter the sweating.
The slab is in a workshop that is not climate controlled but the roof has fiberglass insulation. I live in South Louisiana and we had a snowfall on Xmas Day...very very unusual for this part of the country. The snow was all gone by the next day. The temp today is in the low 70's.
Could the frost (snow) had something to do with the concrete sweating even though it has a been a week since the snow ??
Please advise.
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19 years ago
Not the snow exactly, but the cold air. It cooled the slab and now you open the door and let in that 70 degree moist air. Condensation.
I had it so bad last week when we had a warm spell I could see the water condensing on my cold metal tools and rusting a couple that did not have enough protection.