Do I Need A Vapor Barrier In My Attic

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.

Do i need a vapor barrier in my attic.

The theory is that part of the moisture vapor in the house is actually blocked by the drywall and paint on the. Avoid adding interior vapor barriers where the outer wall construction already includes a material with vapor barrier properties. However all attics vented or unvented and in all climates should have an air barrier such as an airtight drywall ceiling. In areas with high humidity such as greenhouses rooms with spas or swimming pools and bathrooms vapor barriers are often recommended.

Not every wall does. Most authorities recommend vapor barriers in certain situations. 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.

A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. You have loose fill insulation in the attic which doesn t have a vapor barrier. 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.

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. 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. 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. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic.