Vapor Barrier Framing A Basement Wall Against Concrete

Hence it must always be located on the warm in winter side of any insulation.

Vapor barrier framing a basement wall against concrete.

Here are three different types explained. So there is enough gap for air to flow. You should then use fiberglass insulation that has a vapor barrier between the studs with the vapor barrier facing in toward the living space. Without a vapor barrier water vapor flows through the insulation and if the concrete wall is cold enough the water vapor condenses on the concrete and drips down the wall.

Building codes usually require a vapor barrier 4 mil plastic sheeting on exterior basement walls if the framing is attached to masonry or concrete surfaces or if the wood framing butts up against the outer basement walls. It is designed to stop moisture in the form of vapour that is inside the house from moving into the walls and forming condensation or ice. Most jurisdictions require a 4 mil plastic sheet vapor barrier for basement walls against concrete. The water vapor can come through the concrete from the soil or from indoor air that comes in contact with the concrete.

The purpose of the vapor barrier is to stop the warm moist air from condensing on the cool concrete walls. The vapour barrier is more properly called a vapour retarder. Usually that is right behind the drywall. That is if the studs are going to touch the concrete wall.

Or you can leave a 4 inch gap between the studs and concrete wall and probably get away with it. This is accomplished by installing the vapor barrier to the warm room side of the insulation.