Concrete Slab Vapor Barrier Installation

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Concrete slab vapor barrier installation.

Vapor barriers are used because while fresh concrete is poured wet it s not supposed to stay that way. Additionally installation of a vapor barrier may help to contribute to leed. A pro s guide for below slab vapor barrier installation by dan marks 01 14 19 this helpful guide to under slab vapor barrier installation will consider the most common slab designs their terminating edges and how to seal at to the perimeter of your foundation in accordance with your designer s specifications and astm e1643. A concrete vapor barrier is any material that prevents moisture from entering a concrete slab.

If the subbase is sharp angular gravel a thin layer of sand can be placed on top of the gravel subbase next to the vapor barrier. Unroll 1st piece of vapor barrier along one edge of floor. In general place the concrete slab directly on top of the vapor barrier with the subbase below. It needs to dry and then stay dryto avoid flooring problems.

Updated july 10 2020. Tips for concrete floor vapor barrier installation. One of the reasons those old basement floors were like that was because they had no vapor barrier beneath them leaving an easy path for water vapor from the soil to migrate into the slab assuring that the. For a vapor barrier below a concrete floor slab most choose 6 to 10 mil polyethylene.

Using a utility knife cut the length long enough to wrap edges up the wall 3 4 inches. Because extruded polystyrene insulating board will absorb little moisture the vapor barrier can be placed above or below the slab insulation. Puncture studies of 6 8 10 and 20 mil vapor retarder materials have shown that 10 mils is the minimum thickness that should be considered and thicker material may be necessary over angular base materials. If ground conditions require their use a 3 inch 75 millimeter layer of sand over the vapor barrier and under the concrete has been shown to reduce these problems.

Wrap vapor barrier up edge of wall 3 4 inches and tape to wall. The american concrete institute s guide for concrete floor and slab construction recommends that the thickness of the vapor retarder be at least 10 mils. Minimize water vapor moving through a slab by choosing the right vapor barrier and installing it properlyby bill palmer concrete network columnist. Given the many applications a vapor barrier is one of the most critical building components used to prevent indoor air quality issues and minimize moisture related concrete slab and flooring system failures.