How To Seal An Attic Vapor Barrier

Weatherstrip the attic access hatch or door.

How to seal an attic vapor barrier.

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. Finish the wall within a month of installing the barrier to prevent damage to the surface and protect the vapor barrier. Seal the attic access. 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.

Though some batts come with a paper or foil facing that can act as a vapor barrier tom silva prefers to use 6 mil polyethylene sheeting cut to fit between the joists and with seams sealed by foil tape to prevent moisture from seeping into insulation. Apply self adhesive foam weatherstrip tape to the top edge of the stop. Think of a glass of ice water. How to use plastic as a vapor barrier in the walls.

Water vapor in the warmer air of your home begins to condense on the colder surface of the glass of water. Using other kinds of tape will compromise the waterproof seal and render the barrier useless. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. Plug open stud cavities.

Attic vapor barrier detail for cold climates. To be extra certain use a caulk gun to place caulk material around the tape to double seal the barrier. Even though we apply vapor barriers to exterior insulated walls in cold climates it s no longer recommended for ceilings floor of the attic. The plastic bag creates a vapor barrier.

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. In any case the vapor barrier must point to the warm side. The paper facing contains a layer of impermeable asphalt that prevents water vapor from passing through it. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic.