Do I Need A Vapor Barrier In My Attic. The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it. 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. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic.
The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it. No you don t need a vapor retarder class i or otherwise.
Seal the air leakage pathways.
No you don t need a vapor retarder class i or otherwise. The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it. Not every wall does. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one.
