Put Plastic Under Concrete Slab

Aci 302 1 guide for concrete floor and slab construction states that the minimum thickness of an effective vapor barrier is 10 mils.

Put plastic under concrete slab.

Thanks for the question. There are debates about this with varying national regional state and local regulations. Florprufe vapor barriers gcp lied concrete vapor barriers the pros vapor barrier under concrete slab vapour barrier concrete floor problems building concrete vapor barrier what is a. Plastic under concrete floor or not.

Vapour barriers are the black plastic that builders put under residential house slabs. One laboratory drying study indicated that 4 in. Why a plastic vapor barrier under concrete slab mondays withinstall the proper type of vapor barrier siouxland homesare vapor ers necessary for bats and garagesvapour barrier under concrete. This was verfied by some field studies conducted by concrete construction magazine.

They do this for two main reasons. A concrete vapor barrier is simply a sheet of polyethylene plastic visqueen placed directly on top of the sub grade before the concrete floor or slab is poured to help keep moisture from the soil from passing up through the concrete. The rate that moisture escapes from a slab depends on the concrete w c the density of the finish the ambient conditions above the slab and the moisture below the slab. So yes a vapour barrier is required under a concrete slab for a class 1 building a dwelling and for class 10 eg a garage where the slab is continuous with the dwelling.

It doesn t really matter very much whether the pex is near the bottom of the slab in the middle of the slab or at the top of the slab as long as there is plenty of insulation under the slab. Thinner plastic can t stand up to the abuse of construction. Thick concrete samples having a w c 0 50 and sealed from below required 82 days for the vapor emission rate to reach 3 0. One contractor says to put plastic under the concrete it prevents moisture from coming up into the concrete.