Polyethylene Vapor Barrier Under Concrete Slab

Vapor retarders have been used since the 1950s.

Polyethylene vapor barrier under concrete slab.

Many moisture problems associated with interior concrete floors and slabs on grade can be minimized or eliminated by installing a vapor barrier under the concrete. Although it may seem water tight this grade of material allows a lot of water vapor to pass through. Whenever i have seen holes drilled through concrete slabs i have never noticed any degradation in the polyethylene layer. 6 mil poly which is 0 006 inches thick and has a rating of 0 06 perms is also sufficient for most applications but may not be as commonly stocked as 10 mil or 15 mil.

Polyethylene poly plastic sheeting with a thickness of 10 mil or 15 mil is the most commonly used vapor barrier under slabs. Why a plastic vapor barrier under concrete slab mondays with. In fact most professional shed slab builders will install a polyethylene membrane under a shed concrete slab even if it is not specified. 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.

Perminator also helps reduce radon gas from entering the structure. The reason is that the vapour barrier stops moisture from the wet concrete escaping into the ground under the concrete. As long as the polyethylene is protected from sunlight as it obviously is when it is installed under a concrete slab it should last indefinitely. Perminator provides the vapor barrier industry with a highly effective economical choice for helping to reduce the penetration of moisture and water vapor through the slab into the structure thereby helping to reduce fungus mildew and mold growth.

Recently though research has shown that the old traditional layer of 6 mil visqueen polyethylene plastic under the slab is seldom effective for two main reasons. Vapor barrier under concrete slab slab vapor barrier concrete floor problems building vapor barriers in concrete foundations under slab vapor barriers done right vapor ers necessary for bats. 1 mil is equal to 0 001 inch of thickness. The use of a vapor barrier more accurately termed a vapor retarder having a water vapor permeance of less than 0 3 perm is frequently used to retard the flow of moisture through the slab.