Attic Insulation Vapor Barrier

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.

Attic insulation vapor barrier. A vapor barrier basically helps to prevent moisture from entering your home through the ceiling floor or the walls. Adding a second vapor barrier could cause condensation to become trapped in the insulation between the two vapor barriers. Some regions don t require a vapor barrier. 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.

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. This acts as a barrier to keep heated moist air from rising up into the attic during cold weather. A plastic vapor barrier is best installed in a vented attic within climates with over 8 000 heating degree days.

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

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