Attic Ceiling Vapor Barrier

Conversely an air barrier in absence of a vapor barrier can be effective.

Attic ceiling vapor barrier.

We complicate things when we install plastic in ceilings and assume it provides an air barrier. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic. With spray foam unlike with loose fill or batts you must cover the soffit vents they aren t needed to keep the roof cool. A plastic vapor barrier is best installed in a vented attic within climates with over 8 000 heating degree days.

Basement ceiling vapor barrier. Even though we apply vapor barriers to exterior insulated walls in cold climates it s no longer recommended for ceilings floor of the attic. To know if you need a vapor retarder ask yourself a few basic questions. The attic studs and floor of the garage attic are configured in a way to allow the space to be finishe.

Almost 6 years by bv006343. Attic vapor barrier detail for cold climates. 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. The inner surface in colder climates and the outer surface in hot humid climates.

Foam blocks airflow needs no vapor barrier and has a higher r value per inch than loose fill or batts so you ll get more protection with less depth. 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. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. If your climate does not meet these conditions a vapor retarder like latex ceiling paint will work well for your house if you are in all other climates except the hot dry and hot humid.

A vapor barrier in an attic assembly in a severe cold climate in absence of an air barrier will likely be ineffective. In existing spaces oil based paints or vapor barrier latex paints offer an effective moisture barrier. A vapor barrier in an attic assembly in a severely cold climate with the absence of an air barrier will likely be ineffective.