Polyethylene Vapor Barrier Under Concrete Slab

Polyethylene poly plastic sheeting with a thickness of 10 mil or 15 mil is the most commonly used vapor barrier under slabs.

Polyethylene vapor barrier under concrete slab.

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. Why a plastic vapor barrier under concrete slab mondays with. These vapor retarders are typically polyethylene or polyolefin sheeting materials. 1 mil is equal to 0 001 inch of thickness.

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. Perminator also helps reduce radon gas from entering the structure. Vapor retarders have been used since the 1950s.

Although it may seem water tight this grade of material allows a lot of water vapor to pass through. 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. 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. In fact most professional shed slab builders will install a polyethylene membrane under a shed concrete slab even if it is not specified.

The reason is that the vapour barrier stops moisture from the wet concrete escaping into the ground under the concrete. 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. 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. My own advice is to install 6 mil poly and stop worrying.