Attic Insulation Vapor Barrier Or Not

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.

Attic insulation vapor barrier or not.

Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. Call attic insulation toronto for a free quote. 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. 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.

Every construction material has an element of permeability to water which is why you need to have a vapor barrier to damp proof your home and attic. A damp attic can also be the cause of discomfort and lower air quality in the living space. When adding additional insulation to an attic that is already insulated never use insulation with a vapor barrier. The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it.

The heat being lost from the house below warmed up the attic so that moisture was lost through the vents as vapor. In any case the vapor barrier must point to the warm side. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. Reasons for attic insulation vapor barrier.

Not every wall does. 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. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. If you do there is a chance that moisture that has slipped by the first vapor barrier will become trapped by the second vapor barrier decreasing the value of your insulation.

A vapor barrier in an attic assembly in a severely cold climate with the absence of an air barrier will likely be ineffective. Some regions don t require a vapor barrier.