Putting Up A Moisture Barrier Roof

And bring the plastic about 6 in.

Putting up a moisture barrier roof.

Overlap any seams and tape them. Cover the dirt crawlspace with a plastic moisture polyethylene vapor barrier. Sloping the soil away from your home at about 1 2 in. A roof design that includes an adhered roof membrane with multiple layers of insulation with board joints offset and staggered over a vapor retarder air barrier helps lower the risk that air and the moisture it carries will infiltrate the roof system.

After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. If you do not have a vapor barrier on the underside of your roof steel you should have an one inch layer of closed cell spray foam insulation applied to it otherwise it will probably rain in your attic. In very cold climates the use of polyethylene plastic vapor barriers between insulation and interior wallboard may be beneficial provided all air gaps into any wall and ceiling cavities are also blocked. Up the wall and fasten it there.

Per foot is usually the best thing you can do to reduce crawlspace moisture. Not every wall does. Your first job after the studs are in place is to fill those walls with insulation. That reduction of air and moisture infiltration can then help improve roof longevity.