How Important Is Vapor Barrier In Attic

In cold climates the primary purpose of attic or roof ventilation is to maintain a cold roof temperature to control ice dams created by melting snow and to vent moisture that moves from the conditioned space to the attic ventilation acts to bypass the vapour barrier created by most roof.

How important is vapor barrier in attic.

The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below. The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it. Resolution of the vapor barrier debate. A vapor barrier is a thin layer of impermeable material typically polyethylene sheeting included in building construction to prevent moisture from damaging the fabric of the building.

In circumstances where conditions inside a home or office are much different than outdoor conditions water. A plastic vapor barrier is best installed in a vented attic within climates with over 8 000 heating degree days. On the other hand an air barrier a properly detailed air tight drywall ceiling for example in the absence of a vapor barrier can be effective since it stops the flow of vapor laden air. If your climate does not meet these conditions a vapor retarder like latex ceiling paint will work well for your house if you are in all other climates except the hot dry and hot humid.

Some debate still occurs over how necessary vapor barriers are but a consensus is growing closer. 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. Most authorities now agree that vapor barriers are important under certain conditions but not necessarily as a whole house solution for every home. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.

Do not add a vapor barrier on top of the insulation in your attic since the paper facing on the existing insulation is the vapor barrier. Throughout the balance of this digest the terms attic and roof will and can be used interchangeably. 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. Vapor barriers are a must for protecting your home against the damaging effects of moisture and keep your crawl space dry.