Roof Vent Free Area

Universal dormer vent universal dormer vent 135 sq.

Roof vent free area.

The calculations before indicated that we needed 2 square feet of ridge or upper roof ventilation. Calculate or enter the square footage of the attic or area to be vented. The passive vent net free area table gives the net free area ventilation for some common roof and gable passive vents. Should you need to add more air intake ventilation to your attic simply determine the number of vents needed from the table based on your net free area requirements.

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. Sheet metal manufacturers of roof vents roof exhaust fans and solar attic fans. 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. This vent features an 1 8th inch internal aluminum screen to prevent intrusion by birds or large insects.

So we would need at least six metal vents in addition to the lower soffit ventilation to meet minimum ventilation requirements. Made in the usa. Two square feet equals 288 square inches. Base offers added weatherproofing protection and ease of installation.

A normal metal pot vent produces only 50 squares inches of free net area. Roof vents are made from reliable 28 gauge galvanized steel. Large 16 1 2 x 16 1 2 in. Ventsure 4 foot strip heat moisture ridge vent with weather protector moisture barrier.

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. The nfa is the open area that exists for air to pass through. Net free area uv 135.