Vapor Barrier Inside Basement Walls

Not every wall does.

Vapor barrier inside basement walls.

A vapor barrier reduces the movement of water vapor by. Plastic specifically 6 mil polyethylene plastic is. The science of moisture movement. The construction of the wall for instance is vital to the use of a vapor barrier.

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. Whether or not you need a vapor retarder hinges on three main factors. The main concerns are condensation and drying potential. When a vapor barrier is on the side of a wall where the dry air is i e outside in winter or inside in summer moisture problems can occur.

A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. Water vapor can pass through building materials in several ways including direct transmission and by heat transfer but studies suggest that fully 98 percent of the moisture transfer through walls occurs through air gaps including cracks around electrical fixtures and outlets and gaps along baseboards. Without a vapor barrier in place condensation inside the walls could ruin the insulation and promote the growth of harmful mold and bacteria. Polyurethane sheeting is a typical vapor barrier that contractors use to prevent moisture from penetrating the walls of a basement.

When the mold grows it will spread to. A vapor barrier s job is to keep water vapor in humid air from diffusing through one side of a wall and finding a cool surface inside the wall. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. 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.

1 on the interior wall between the heated and unheated portion of the basement i would not use with a vapor barrier. A vapor barrier is also helpful to keeping a basement insulated and warm.