Attic Insulation Moisture Barrier

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

Attic insulation moisture barrier.

Adding a second vapor barrier could cause condensation to become trapped in the insulation between the two vapor barriers. They don t however reduce heat conduction like thermal insulation materials. 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. Not every wall does.

After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. The heat being lost from the house below warmed up the attic so that moisture was lost through the vents as vapor. The barriers consist of a highly reflective material that reflects radiant heat rather than absorbing it.

The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below. Since some leakage of moisture into the insulation in inevitable murphy s law you want it to be able to freely escape from the insulation into the attic. In any case the vapor barrier must point to the warm side. Not be trapped inside.

Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. Never compress or fluff your insulation. 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.

Vapor barriers in attics should only be installed on one side of the insulation. Radiant barriers are installed in homes usually in attics primarily to reduce summer heat gain and reduce cooling costs. This really helps prevent trapped moisture between a traditional vapor barrier and the drywall.