Attic Ceiling Vapor Barrier

A vapor barrier in an attic assembly in a severely cold climate with the absence of an air barrier will likely be ineffective.

Attic ceiling vapor barrier.

During the energy crisis of the 1970s a prevailing belief took root where it was thought that tightly sealing walls and ceilings with a vapor barrier was essential to blocking heat transference and reducing energy costs it was soon determined however that unless the seal was absolute moisture that did get into sealed walls could create serious structural problems and health issues such as. Even though we apply vapor barriers to exterior insulated walls in cold climates it s no longer recommended for ceilings floor of the attic. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. Basement ceiling vapor barrier.

Now with attic insulation heat is no longer lost from the living space such that. Attic insulation should always be installed with the paper backing facing toward the living space the ceiling in this case. 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. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets.

Some regions don t require a vapor barrier. Whether or not you need a vapor retarder hinges on three main factors your climate your home and the location of the wall you re insulating. Before the introduction of attic insulation attics in cold climates were poorly insulated and plastic ceiling vapor barriers were omitted. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic.

Attic vapor barrier detail for cold climates. The heat being lost from the house below warmed up the attic so that moisture was lost through the vents as vapor. On the other hand an air barrier a properly detailed air tight drywall ceiling for example in the absence of a vapor barrier can be effective since it stops the flow of vapor laden air. This acts as a barrier to keep heated moist air from rising up into the attic during cold weather.

To know if you need a vapor retarder ask yourself a few basic questions. Almost 6 years by bv006343.