Plastic Sheet Under Concrete Slab

This plastic sheet is in direct contact with the concrete as it should be in a rational world.

Plastic sheet under concrete slab.

Polyethylene sheeting under concrete slab under slab vapor retarders play a very important role in retarding moisture from coming up through the concrete and into the structure. 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. This heavy duty plastic is commonly used under concrete slabs as a vapor barrier on top of freshly poured slabs as a curing blanket and as a temporary cover for equipment and supplies. Plastic sheeting is a general purpose plastic film for use in a variety of construction and diy projects.

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. Although it may seem water tight this grade of material allows a lot of water vapor to pass through. Vapor retarders have been used since the 1950s. Concrete contractors learned that a layer of poly helps to keep a slab dry because it stops upward vapor diffusion from the soil.

The hdx 20 ft. This plastic can be used to cover crawl spaces and as a temporary cover for equipment and supplies. 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. This extra heavy duty plastic can be used under concrete slabs as a vapor barrier and on top of freshly poured slabs as a curing blanket.

Today most experts feel very strongly that engineered films designed specifically for use as vapor retarders should be used as vapor retarders. Almost everywhere except california that slabs are placed on the ground a plastic sheet a vapor barrier is located directly under the concrete slab and on top of the ground photograph 1. Commonly used under concrete slabs as a vapor barrier and on top of freshly poured slabs as a curing blanket.