Attic Insulation Vapor Barrier

When adding additional insulation to an attic that is already insulated never use insulation with a vapor barrier.

Attic insulation vapor barrier.

The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below. A vapor barrier basically helps to prevent moisture from entering your home through the ceiling floor or the walls. 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. 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.

Some regions don t require a vapor barrier. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. This acts as a barrier to keep heated moist air from rising up into the attic during cold weather. It is a known fact that moisture in the air can trigger certain disorders and aggravate particular medical conditions such as hay fever asthma etc.

Adding a second vapor barrier could cause condensation to become trapped in the insulation between the two vapor barriers. A plastic vapor barrier is best installed in a vented attic within climates with over 8 000 heating degree days. Attic insulation should always be installed with the paper backing facing toward the living space the ceiling in this case. In any case the vapor barrier must point to the warm side.

The following are a few simple steps to help you undertake the task properly so your vapor barrier retains heat without damaging 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.