Best Practices Attic Ventilation

The average family of four generates 2 to 4 gallons of water vapor a day through activities such as cooking cleaning showering laundry and breathing.

Best practices attic ventilation.

From the roof s peak. Intake vents located at the lowest part of the roof under the eaves allow cool air to enter the attic. For both attics and cathedral ceilings roof ventilation works best when it is balanced between high and low to take advantage of natural convection figure 2 55 at left. Mark attic roof air vent locations.

Ventilation helps even more when used in combination with radiant barriers. The recommended ventilation ratio to provide for vented attic assemblies when an air barrier is present is the 1 300 ratio as specified by most building codes. Hot air exhaust vents located at the peak of the roof allow hot air to escape. How to install roof vents.

If your home is fitted solely with small gable end vents or a ventilator high in the roof you might want to consider adding soffit vents to increase airflow. Cut the hole for roof vents. The international residential code irc provision for attic ventilation requires a ratio of one square foot of net free open ventilation area for every 150 to 300 square feet of attic square footage. Additionally attic ventilation is a key ingredient in the defense against ice dams in snow and ice climates.

This configuration also tends to evenly wash the entire underside of the roof surface with ventilation air. Cut the shingles for roof vents. Experts recommend using attic ventilation in hot climates as part of an overall strategy to reduce cooling loads. Adapted paraphrased with permission from best practices guide to residential construction chapter on best roofing practices.

Attic ventilation can help remove the water vapor safely. Roof insulation thermal resistance at roof perimeter should be equal or greater to thermal resistance of exterior wall. Drive nails up through the sheathing and.