Vapour Barrier Attic Floor

Adding a second vapor barrier could cause condensation to become trapped in the insulation between the two vapor barriers.

Vapour barrier attic floor.

Begin the process of fitting a vapor barrier for attic insulation by preparing the space for the job. Below grade walls and floor slabs transmit ground moisture through concrete walls or slabs. Attic vapor barrier detail for cold climates. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.

In the typical crawl space with a dirt floor a 6 mil plastic vapor barrier is used to prevent moisture from the soil from coming up into the crawl space area. Insulation provides a barrier between vapor and the structure. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic. Some regions don t require a vapor barrier.

If there is limited lighting find a way to provide more so you can see what you re doing. Everyday activities such as cooking washing and bathing add moisture to the air in your home in the form of water vapor. 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. This vapor can become trapped inside walls resulting in mold and mildew growth which can damage your home and present a potential health concern.

Very hot and humid climates may benefit from an exterior vapor barrier that keeps outside humidity from penetrating into walls. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. A vapor barrier against the concrete surface is generally recommended before wood framing or flooring materials are installed. Whether or not you need a vapor retarder hinges on three main factors your climate your home and the location of the wall you re insulating.

In any case the vapor barrier must point to the warm side. That vapor barrier is laid directly. Remove any transferable items from the attic so that they do not get in the way as you work. 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.

Even though we apply vapor barriers to exterior insulated walls in cold climates it s no longer recommended for ceilings floor of the attic.