How To Seal An Attic Vapor Barrier

If you re insulating from scratch put the right vapor barrier in the right place.

How to seal an attic vapor barrier. Think of a glass of ice water. Even though we apply vapor barriers to exterior insulated walls in cold climates it s no longer recommended for ceilings floor of the attic. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. Apply self adhesive foam weatherstrip tape to the top edge of the stop.

Finish the wall within a month of installing the barrier to prevent damage to the surface and protect the vapor barrier. Because it s nearly impossible to seal penetrations in the ceiling the reality is water vapor will get into the attic. Weatherstrip the attic access hatch or door. Attic vapor barrier detail for cold climates.

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. 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. Plug open stud cavities. The plastic bag creates a vapor barrier.

Water vapor in the warmer air of your home begins to condense on the colder surface of the glass of water. To be extra certain use a caulk gun to place caulk material around the tape to double seal the 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.

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. Cut 1 3 boards to fit the perimeter of the opening and nail them on with 6d finish nails. Seal the attic access. Using other kinds of tape will compromise the waterproof seal and render the barrier useless.