Vapor Barrier Roof Insulation

What is a vapour barrier.

Vapor barrier roof insulation.

After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. Vapor barriers applied over the face of the insulation provide additional benefits in the fight against moisture. A vapour barrier sometimes referred to as vapour retarder is typically a plastic or foil sheet used for damp proofing to prevent interstitial condensation from forming in various building assemblies such as walls roofs foundations and floors. In any case the vapor barrier must point to the warm side.

This barrier is meant to keep moisture from getting to the insulation in the walls and ceilings and it is required by building codes when insulating most houses. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. An introduction to vapour barriers and vapour retarders. Vapor barriers usually composed of a thin film such as polyethylene vapor barriers are used to retard or prevent water vapor diffusion into a wall ceiling or floor during the cold winter.

A roof design that includes an adhered roof membrane with multiple layers of insulation with board joints offset and staggered over a vapor retarder air barrier helps lower the risk that air and the moisture it carries will infiltrate the roof system. Not every wall does.