Polyethylene Vapor Barrier Under Concrete Slab

Install the proper type of vapor barrier siouxland homes.

Polyethylene vapor barrier under concrete slab.

These vapor retarders are typically polyethylene or polyolefin sheeting materials. My own advice is to install 6 mil poly and stop worrying. Polyethylene poly plastic sheeting with a thickness of 10 mil or 15 mil is the most commonly used vapor barrier under slabs. 1 mil is equal to 0 001 inch of thickness.

Whenever i have seen holes drilled through concrete slabs i have never noticed any degradation in the polyethylene layer. Although it may seem water tight this grade of material allows a lot of water vapor to pass through. 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. Why a plastic vapor barrier under concrete slab mondays with.

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 retarders have been used since the 1950s. 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.

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. 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 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. In fact most professional shed slab builders will install a polyethylene membrane under a shed concrete slab even if it is not specified.