Attic Insulation Moisture 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.

Attic insulation moisture barrier.

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. If you live in a cold climate place the vapor barrier between the interior of your home and the insulation. Over time this trapped moisture can rot the wood framing in your attic or cause mold and mildew to appear. In any case the vapor barrier must point to the warm side.

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. Not every wall does. Lucyna de barbaro posted in energy efficiency and durability on october 4 2015 02 12am hello i am helping family with their attic insulation in east lansing mi. The attic has 2 ridge vents and 2 additional netted vents in the roof more centrally located.

The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below. Hence the need to reduce moisture flow into the attic and the need for a vapor barrier. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. When adding additional insulation to an attic that is already insulated never use insulation with a 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 the following are a few simple steps to help you undertake the task properly so your vapor barrier retains heat without damaging the insulation. Vapor barriers keep the air moisture in your house from condensing in the insulated cavities. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. With the added insulation the attic stayed cold and so did the ventilating air from outside which was now unable to effectively remove attic moisture.

Vapor barrier in attic. Adding a second vapor barrier could cause condensation to become trapped in the insulation between the two vapor barriers. 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. Newly purchased house 75 years old.

This worked well until we added large quantities of attic insulation.