Do I Need A Vapor Barrier For Attic Insulation

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

Do i need a vapor barrier for attic insulation.

The heat being lost from the house below warmed up the attic so that moisture was lost through the vents as vapor. Foam blocks airflow needs no vapor barrier and has a higher r value per inch than loose fill or batts so you ll get more protection with less depth. 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. 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. Attic insulation should always be installed with the paper backing facing toward the living space the ceiling in this case. Then cover the foam with drywall as required for fire safety. Now with attic insulation heat is no longer lost from the living space such that moisture may remain trapped in the attic vapor barriers were therefore necessary to reduce moisture flow into the attic.

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. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic. Our insulation vapor barrier can also reduce condensation mold and degradation by controlling water vapor migration.

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

With spray foam unlike with loose fill or batts you must cover the soffit vents they aren t needed to keep the roof cool. You can forego the plastic and use a vapor retarder kraft faced insulation or latex ceiling paint in all other climates except hot humid or hot dry climates.