Attic Ceiling Vapor Barrier

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.

Attic ceiling 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. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. Some insulated ceiling assemblies include a vapor barrier to prevent moisture in the air from migrating from the warm heated side of the ceiling to the cold outer area of the assembly where it. The attic studs and floor of the garage attic are configured in a way to allow the space to be finishe.

Even though we apply vapor barriers to exterior insulated walls in cold climates it s no longer recommended for ceilings floor of the attic. In existing spaces oil based paints or vapor barrier latex paints offer an effective moisture barrier. 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. A vapor barrier in an attic assembly in a severely cold climate with the absence of an air barrier will likely be ineffective.

We complicate things when we install plastic in ceilings and assume it provides an air barrier. Basement ceiling vapor barrier. 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 vapor barrier in an attic assembly in a severe cold climate in absence of an air barrier will likely be ineffective.

Conversely an air barrier in absence of a vapor barrier can be effective. Then cover the foam with drywall as required for fire safety. A plastic vapor barrier is best installed in a vented attic within climates with over 8 000 heating degree days. Vapor barriers are usually best installed on the side of the wall that experiences the hotter temperature and moister conditions.

The inner surface in colder climates and the outer surface in hot humid climates. Almost 6 years by bv006343. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic.