Attic Insulation Vapor Barrier Cellulose

Should you install a vapor barrier over preexisting attic insulation.

Attic insulation vapor barrier cellulose.

The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it. The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below. If you decide to go ahead with the plan to install cellulose on the attic floor you don t need a vapor barrier. The us department of energy classifies cellulose insulation as a class iii vapor retarder.

A vapor barrier is not only unnecessary but also can be potentially harmful especially during the summer months in air conditioned buildings when warm moist air passes through wall assemblies and condenses on the outside of the cool poly vapor barrier. The best approach for a vented attic in a cold climate is installing a layer of drywall with a good coat of latex paint the paint creates a semi permeable vapor barrier. It s actually a smart vapor retarder since its permeability decreases as moisture content increases. The hygroscopic nature of cellulose insulation allows it to manage and wick moisture from areas of greater to lesser concentrations thus preventing damaging amounts of moisture from accumulating.

With our vapor barrier installation services there will be no issue of the crawl space of your home becoming a residence for pests bats and rodents. But you do need to perform air sealing work before beginning the insulation job. This article explains the necessary work. Not be trapped inside.

Air sealing an attic. Vapor barriers in attics should only be installed on one side of the insulation. The best way to answer this question in addition to considering the factors above would be to talk to a professional. They help keep moisture from migrating into walls by diffusion but still allow for drying so it doesn t get trapped.

Insulation labs is a name to reckon with for efficient vapor barrier installation services.