Attic Insulation Ceiling Vapor Barrier

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

Attic insulation ceiling vapor barrier.

The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below. 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. When adding additional insulation to an attic that is already insulated never use insulation with a vapor barrier.

The heat being lost from the house below warmed up the attic so that moisture was lost through the vents as vapor. 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. Whether your vapor barrier is a facing or a film it must be placed on the warm in winter side of the wall. Before the introduction of attic insulation attics in cold climates were poorly insulated and plastic ceiling vapor barriers were omitted.

Some regions don t require a vapor barrier. Attic insulation should always be installed with the paper backing facing toward the living space the ceiling in this case. Not every wall does. 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. Now with attic insulation heat is no longer lost from the living space such that. 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. A vapor barrier in an attic assembly in a severely cold climate with the absence of an air barrier will likely be ineffective.

After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. On the other hand an air barrier a properly detailed air tight drywall ceiling for example in the absence of a vapor barrier can be effective since it stops the flow of vapor laden air.