Vapor Barrier Blown In Insulation Attic

R value declines by as much as 50 percent at temps below 0 degrees f.

Vapor barrier blown in insulation attic.

Most forms of attic insulation benefit from the addition of a vapor barrier to protect them from the harmful effects of moisture which can reduce their effectiveness over time the following are a few simple steps to help you undertake the task properly so your vapor barrier retains heat without damaging the insulation. Some regions don t require a vapor barrier. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. Vapor barriers keep the air moisture in your house from condensing in the insulated cavities.

Whether your vapor barrier is a facing or a film it must be placed on the warm in winter side of the wall. 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. Fluffy bits of spun glass that are noncombustible and can t decay. The heat being lost from the house below warmed up the attic so that moisture was lost through the vents as vapor.

Attic insulation new construction or retrofit work. The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. Not every wall does.

A common misconception is that all insulations require vapor barriers in all situations. 70 to 75 per sq. 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. Cima does not recommend the use of vapor barriers with cellulose insulation except in circumstances of exceptionally high moisture levels such as an indoor pool facility or very cold climates.

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. If you live in a cold climate place the vapor barrier between the interior of your home and the insulation. Blowing insulation into walls is best left to the pros because it involves drilling into stud spaces that may contain electrical. Now with attic insulation heat is no longer lost from the living space such that moisture may remain trapped in the attic vapor barriers were therefore necessary to reduce moisture flow into the attic.