Do I Need A Vapor Barrier In My Attic

Avoid adding interior vapor barriers where the outer wall construction already includes a material with vapor barrier properties.

Do i need a vapor barrier in my attic.

Not every wall does. By the time you paint the drywall though you ve brought it into the class iii vapor retarder range between 1 and 10 perms and even less water vapor will diffuse through. The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it. In hot dry climates your attic can be vented though like in hot humid climates you should not install any vapor retarder or barrier.

Seal the air leakage pathways. In areas with high humidity such as greenhouses rooms with spas or swimming pools and bathrooms vapor barriers are often recommended. However all attics vented or unvented and in all climates should have an air barrier such as an airtight drywall ceiling. A vapor barrier in an attic assembly in a severely cold climate with the absence of an air barrier will likely be ineffective.

No you don t need a vapor retarder class i or otherwise. The theory is that part of the moisture vapor in the house is actually blocked by the drywall and paint on the. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one.

Attic vapor barrier detail for cold climates even though we apply vapor barriers to exterior insulated walls in cold climates it s no longer recommended for ceilings floor of the attic. Hi beth do not add a vapor barrier on top of the insulation in your attic since the paper facing on the existing insulation is the vapor barrier. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. Most authorities recommend vapor barriers in certain situations.