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.
Attic insulation moisture barrier.
This worked well until we added large quantities of attic insulation.
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.
A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.
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.
Whether your vapor barrier is a facing or a film it must be placed on the warm in winter side of the wall.
Over time this trapped moisture can rot the wood framing in your attic or cause mold and mildew to appear.
Vapor barriers keep the air moisture in your house from condensing in the insulated cavities.
When adding additional insulation to an attic that is already insulated never use insulation with 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.
Some regions don t require a vapor barrier.
The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below.
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.
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.
Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets.
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.
In any case the vapor barrier must point to the warm side.
Vapor barrier in attic.
Newly purchased house 75 years old.
Hence the need to reduce moisture flow into the attic and the need for a vapor barrier.
The attic has 2 ridge vents and 2 additional netted vents in the roof more centrally located.