Attic Insulation Ceiling Vapor Barrier

Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets.

Attic insulation ceiling vapor barrier.

Now with attic insulation heat is no longer lost from the living space such that. 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. Some regions don t require a vapor barrier.

Before the introduction of attic insulation attics in cold climates were poorly insulated and plastic ceiling vapor barriers were omitted. 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. 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.

A vapor barrier in an attic assembly in a severely cold climate with the absence of an air barrier will likely be ineffective. If you live in a cold climate place the vapor barrier between the interior of your home and the insulation. This acts as a barrier to keep heated moist air from rising up into the attic during cold weather. 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.

The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. Whether your vapor barrier is a facing or a film it must be placed on the warm in winter side of the wall. Not every wall does.

If you live in a hot humid climate place the vapor barrier toward the outside of the wall cavity. Attic insulation should always be installed with the paper backing facing toward the living space the ceiling in this case.