Roof Vent Free Area

The key to effective venting is to balance air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge.

Roof vent free area.

Ideally the nfa of the soffits should be equal or greater than that of the ridge vent and in no case should the amount of exhaust ventilation exceed the amount of intake ventilation. Balanced ventilation will prolong the life of your roof while providing energy savings and comfort. Universal dormer vent universal dormer vent 135 sq. Active ventilation products inc.

Net free area uv 135. The nfa is the open area that exists for air to pass through. Made in the usa. Ventsure 4 foot strip heat moisture ridge vent with weather protector moisture barrier.

Base offers added weatherproofing protection and ease of installation. A normal metal pot vent produces only 50 squares inches of free net area. Large 16 1 2 x 16 1 2 in. Build your roof empowers you to select each layer and component that goes into your total protection roofing system so that you get the roof you want to protect your home.

This vent features an 1 8th inch internal aluminum screen to prevent intrusion by birds or large insects. The calculations before indicated that we needed 2 square feet of ridge or upper roof ventilation. Roof vents are made from reliable 28 gauge galvanized steel. Two square feet equals 288 square inches.

Venting products are normally rated with a net free area nfa. Calculate or enter the square footage of the attic or area to be vented. Sheet metal manufacturers of roof vents roof exhaust fans and solar attic fans.