Moisture Barrier In Concrete Slab

Vapor and gas barriers.

Moisture barrier in concrete slab.

Ft 24 hours in 82 days with a vapor barrier compared to 144 days when exposed to vapor from below. A concrete vapor barrier is any material that prevents moisture from entering a concrete slab. Uncontrolled water vapor through concrete slabs has cost building owners designers and contractors billions of dollars. It needs to dry and then stay dry to avoid flooring problems.

Without a vapor barrier the relative humidity in the slab just below the surface can often be 100. Aci 302 2r 06 guide for concrete floors that receive moisture sensitive flooring materials estimates that concrete with a w c of 0 5 will dry to an mver of 3 pounds 1000 sq. These plates must be made of pressure. Sole plates or sill plates are the first pieces of framing lumber placed in home construction.

But they have also proven to be beneficial in reducing failures of moisture sensitive flooring materials adhesives and coatings caused by excessive emission of moisture vapor from concrete slabs. These principles mean that if the relative humidity in the concrete slab is different than the relative humidity of the air above the slab then moisture is going to try to move in or out of the slab. The use of underslab vapor barriers is the best method and most economical solution for controlling water vapor migration through concrete slabs. Vapor barriers are used because while fresh concrete is poured wet it s not supposed to stay that way.

To take it one step further astm e 1745 class a vapor barriers products with less than 0 01 perms are the best approach to protecting your concrete slab and components moisture sensitive floor and iaq from moisture sources below. 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. Sometimes providing adequate time for natural drying of concrete slab would solve the problem. A low permeance vapor barrier retarder can effectively keep below slab moisture from reaching the flooring system.