Vapor Barrier Walls Concrete

Below grade walls and floor slabs transmit ground moisture through concrete walls or slabs.

Vapor barrier walls concrete.

A concrete vapor barrier is any material that prevents moisture from entering a concrete slab. A vapor barrier against the concrete surface is generally recommended before wood framing or flooring materials are installed. While current practices versus old methods are under some debate the rule of thumb is that a vapor barrier is installed on the warm side of the insulation in a wall. If you have a framed wall that is adjacent to a concrete foundation wall where the vapor barrier is next to the drywall in front of the studs the fiberglass insulation gets wet and becomes a breeding ground for mold.

It needs to dry and then stay dryto avoid flooring problems. Thus vapor barriers are also. 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. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.

The construction of the wall for instance is vital to the use of a vapor barrier. Very hot and humid climates may benefit from an exterior vapor barrier that keeps outside humidity from penetrating into walls.