Vapor Barrier For Blown In Insulation

A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.

Vapor barrier for blown in insulation.

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. Vapor barriers keep the air moisture in your house from condensing in the insulated cavities. Settlement vapor barriers condensation r values voids this document assists building buyers owners or inspectors who need to diagnose identify or improve building insulation for new construction or retrofit and energy savings projects. Vapor barriers applied over the face of the insulation provide additional benefits in the fight against moisture.

Cima does not recommend the use of vapor barriers with cellulose insulation except in circumstances of exceptionally high moisture levels such as an indoor pool facility or very cold climates. This acts as a barrier to keep heated moist air from rising up into the attic during cold weather. Attic insulation should always be installed with the paper backing facing toward the living space the ceiling in this case. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one.

Whether your vapor barrier is a facing or a film it must be placed on the warm in winter side of the wall. A common misconception is that all insulations require vapor barriers in all situations. Research has shown that this is incorrect.