Attic Insulation Vapor Barrier

In any case the vapor barrier must point to the warm side.

Attic insulation vapor barrier.

Some regions don t require a vapor barrier. 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. The heat being lost from the house below warmed up the attic so that moisture was lost through the vents as vapor.

Vapor barriers keep the air moisture in your house from condensing in the insulated cavities. 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. If you live in a cold climate place the vapor barrier between the interior of your home and the insulation. 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.

Whether your vapor barrier is a facing or a film it must be placed on the warm in winter side of the wall. The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below. 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. When adding additional insulation to an attic that is already insulated never use insulation with a vapor barrier.

Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. This barrier is meant to keep moisture from getting to the insulation in the walls and ceilings and it is required by building codes when insulating most houses. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it.