Roof Vent Free Area

Base offers added weatherproofing protection and ease of installation.

Roof vent free area.

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. Sheet metal manufacturers of roof vents roof exhaust fans and solar attic fans. The calculations before indicated that we needed 2 square feet of ridge or upper roof ventilation. This vent features an 1 8th inch internal aluminum screen to prevent intrusion by birds or large insects.

Calculate or enter the square footage of the attic or area to be vented. The nfa is the open area that exists for air to pass through. Roof vents are made from reliable 28 gauge galvanized steel. 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.

Made in the usa. Active ventilation products inc. 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. Net free area uv 135.

Universal dormer vent universal dormer vent 135 sq. Ventsure 4 foot strip heat moisture ridge vent with weather protector moisture barrier. The passive vent net free area table gives the net free area ventilation for some common roof and gable passive vents. Balanced ventilation will prolong the life of your roof while providing energy savings and comfort.

So we would need at least six metal vents in addition to the lower soffit ventilation to meet minimum ventilation requirements. 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. Two square feet equals 288 square inches.