SLAB FOUNDATION

[BOIEMACHO]

Hi, I am planning to build a 24' x 24' home slab foundation in tropical area. I am concern about the humidity because of the hot weather. I am thinking of laying a plastic sheets before pouring the cement. Do you think that is a good idea?

[FrankInWI]

I'd be talking to the local contractors...and the county officials related to building.  Sometimes local answers to local issues are very benficial.

[John Raabe]

A moisture barrier under a slab is common in wet soils. Depending on local conditions you may want to 2" of sand on top before pouring the slab.

Local issues can come into play here as FrankInWI mentions. There may also be other local issues such a termite barriers.

[BOIEMACHO]

A moisture barrier under a slab is common in wet soils. Depending on local conditions you may want to 2" of sand on top before pouring the slab.

Local issues can come into play here as FrankInWI mentions. There may also be other local issues such a termite barriers.

Thanks, I do not even think that it will also serve as termite barriers. Maybe I can cement the outside perimeter and lay plastic sheets before pouring the cement.

[John Raabe]

One concern slab installers have in hot climates is that the concrete can set up TOO QUICKLY if poured directly on top of a poly moisture barrier. That is why some put down 2" of sand to absorb moisture and slow the cure. At least that is my understanding - check with the installer. The poly will help control ground insects but termites and other wood eating critters can come by air or soil tubes up into framing. Clever devils these!

[BOIEMACHO]

Thank you for the information.