Admitting Air Into The Attic

Attic air may contain contaminants including mouse droppings fiberglass asbestos and mold.

Admitting air into the attic.

This prevents cold outside air from traveling through the attic and into the living area of the home. In these rare cases plumbers use an air admittance valve. These vents are installed directly into the blocking between the exposed rafters. If a bath fan dumps into the attic that is very warm very moist air entering a cold space.

If you have air admittance valves in the attic and they fail to close then it is always possible that the air handler can draw in the sewer gases as they escape and distribute them through the house. It may seem counterproductive to go to the trouble of improving attic insulation only to then add vents that admit outside air into the attic but fresh air plays a vital role in roof health. Used most commonly at an island sink or vanity the vents are also located in the attic to prevent the roof penetrations as seen above on the front roof line elevation. Or if there are lots of holes between the house and the attic warm moist air can rise into the attic from the house.

Roof vents ridge vents and gable vents are used as outlets in the attic. Air admittance valves aka studor vents are negative pressure activated one way mechanical valves. If this contaminated air gets sucked into the living space it can cause health problems for the occupants. Intake vents located at the lowest part of the roof under the eaves allow cool air to enter the attic.

Hot air exhaust vents located at the peak of the roof allow hot air to escape. Air from the living space below can carry water vapor into the attic hitting a cold place in the attic and causing rot and mold growth. Cold air doesn t hold as much moisture so it condenses on the roof deck. In texas the builders place the air handlers for the heating and cooling systems up in the attic.

Outlet vents allow the air to escape from your attic and are installed at a higher elevation.