Vapor Barrier For Concrete Block Walls

Eliminating the movement of moisture into a building reduces the likelihood of mold and other problems caused by the buildup of water.

Vapor barrier for concrete block walls.

Cover exposed foundation walls with 1 1 2 in. Of rigid moisture proof insulation. This wall assembly will dry from the vapor barrier inwards and will dry from the vapor barrier outwards. Not every wall does.

A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. Not to be confused with a vapor barrier which is placed on the warm side of the wall just in front of the insulation and behind the drywall a moisture barrier goes against the basement wall. Below grade walls and floor slabs transmit ground moisture through concrete walls or slabs.

Very hot and humid climates may benefit from an exterior vapor barrier that keeps outside humidity from penetrating into walls. Attaching vapor barrier to a concrete wall can help to prevent the movement of moisture through the concrete and into the building. Concrete block with interior frame wall cavity insulation and brick or stone veneer applicability limited to mixed humid hot humid mixed dry hot dry and marine regions should not be used in cold very cold and subarctic. We used thermax brand available through lumberyards of polyethylene vapor barrier because it doesn t require an additional fire barrier.

A vapor barrier against the concrete surface is generally recommended before wood framing or flooring materials are installed. Since warmer air has more moisture vapor will move to. This not only insulates the walls but also keeps rising dampness in the concrete from getting into the crawlspace. By nature vapor travels from areas of higher concentrations to lower.