Vapor Barrier For Blown In Insulation In Attic

Click to enlarge graphic doe suggestion of a vapor barrier in double wall construction may not be necessary when using cellulose insulation in warmer climates.

Vapor barrier for blown in insulation in attic.

The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. There might always be water vapor in the insulation but it cannot condense because the sheathing is warm. Hence the need to reduce moisture flow into the attic and the need for a vapor barrier.

Cima can supply you with data regarding vapor barriers and cellulose insulation for your location. The insulation keeps the sheathing warm enough to prevent condensation of the water vapor. 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. 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.

This worked well until we added large quantities of attic insulation. Attic vapor barrier detail for cold climates 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. Fluffy bits of spun glass that are noncombustible and can t decay. Whether using loose fill or batts put the vapor barrier closest to the warm side of your installation where hot moist air would get in facing the house s interior in cold climates beneath floor insulation and the attic s interior in hot climates on top of floor insulation.

If your climate does not meet these conditions a vapor retarder like latex ceiling paint will work well for your house if you are in all other climates except the hot dry and hot humid. The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below. Insulation labs is a name to reckon with for efficient vapor barrier installation services. With the added insulation the attic stayed cold and so did the ventilating air from outside which was now unable to effectively remove attic moisture.

After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. Some regions don t require a vapor barrier. Attic insulation new construction or retrofit work. Not every wall does.