Do I Need A Vapor Barrier In Attic

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.

Do i need a vapor barrier in attic.

After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic. Not every wall does.

A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. In hot dry climates your attic can be vented though like in hot humid climates you should not install any vapor retarder or barrier. You have loose fill insulation in the attic which doesn t have a vapor barrier. 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.

However all attics vented or unvented and in all climates should have an air barrier such as an airtight drywall ceiling.