Attic Insulation Ceiling Vapor Barrier

Not be trapped inside.

Attic insulation ceiling vapor barrier.

Never compress or fluff your insulation. However all attics vented or unvented and in all climates should have an air barrier such as an airtight drywall ceiling. This acts as a barrier to keep heated moist air from rising up into the attic during cold weather. Plastic vapor barriers should only be installed in vented attics in climates with more than 8 000 heating degree days.

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. Due to this inevitable fact it s actually better to omit a vapor barrier between the insulation and drywall of the ceiling below the attic. Attic moisture was then picked up and vented to exterior. 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.

Handy homeowners can install blown in insulation in the attic. With added insulation attic and ventilating outside air both stayed cold unable to effectively remove attic moisture. Before the introduction of attic insulation attics in cold climates were poorly insulated and plastic ceiling vapor barriers were omitted. Attic insulation should always be installed with the paper backing facing toward the living space the ceiling in this case.

After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. Hence a need to reduce moisture flow into the attic and add a vapor barrier. 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. Since some leakage of moisture into the insulation in inevitable murphy s law you want it to be able to freely escape from the insulation into the attic.

With spray foam unlike with loose fill or batts you must cover the soffit vents they aren t needed to keep the roof cool. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. Vapor barriers in attics should only be installed on one side of the insulation. Adding a second vapor barrier could cause condensation to become trapped in the insulation between the two vapor barriers.

Blowing insulation into walls is best left to the pros because it involves drilling into stud spaces that may contain electrical.