Attic Air Flows

The insulation will resist heat transfer into the house.

Attic air flows.

Air flows in through the soffit vents and out through the roof vents. Static roof line vents are effective for ventilation but generally aren t recommended due to issues with leaks. If you see dampness or frost you need better roof ventilation and some attic vents. This is normally the point where air enters your attic.

Hot air exhaust vents located at the peak of the roof allow hot air to escape. Gable vents may circulate air through only a small percentage of your attic. Intake vents located at the lowest part of the roof under the eaves allow cool air to enter the attic. In the summer natural air flow in a well vented attic moves super heated air out of the attic protecting roof shingles and removing moisture.

For the best results place roof ventilation near the roof s peak and soffit vents in the eaves. Grab a flashlight and inspect your attic during the winter. These fans may be controlled by a switch or a thermostat which detects heat build up in the attic space and automatically exhausts the attic space. Fans and vents may be installed on the roof system that will draw the air out of the attic space and exhaust it to the exterior.

If the soffit of your home isn t perforated to allow air movement either replace it with perforated soffit or install round air vents under the eaves to allow air flow. Nfa is the unobstructed area through which air can pass through a vent usually measured in square inches. Ventilation manufacturers assign an nfa value to the non motorized vents they make. Vents come in various styles.

The ice traps water behind it allowing the water to seep back under the shingles and leak through the roof. The most common mistake homeowners make when installing insulation is to block the flow of air at the eaves. Whole house fans powered attic fans. Make sure there is air flow from the eaves.

Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. Intake exhaust airflow in a house attic square footage 2 square inches of exhaust and square inches of intake net free area nfa needed. These ice dams form when warm attic air melts the snow on the roof and the water refreezes along the colder edge of the roof. Soffit vents may leave air trapped at the top of your attic.