Roof Vent Free Area

So we would need at least six metal vents in addition to the lower soffit ventilation to meet minimum ventilation requirements.

Roof vent free area.

The calculations before indicated that we needed 2 square feet of ridge or upper roof ventilation. Ventsure 4 foot strip heat moisture ridge vent with weather protector moisture barrier. Two square feet equals 288 square inches. Venting products are normally rated with a net free area nfa.

Active ventilation products inc. Made in the usa. This vent features an 1 8th inch internal aluminum screen to prevent intrusion by birds or large insects. The passive vent net free area table gives the net free area ventilation for some common roof and gable passive vents.

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. 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. Universal dormer vent universal dormer vent 135 sq.

A normal metal pot vent produces only 50 squares inches of free net area. Balanced ventilation will prolong the life of your roof while providing energy savings and comfort. Large 16 1 2 x 16 1 2 in. Roof vents are made from reliable 28 gauge galvanized steel.

Base offers added weatherproofing protection and ease of installation. The nfa is the open area that exists for air to pass through. 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.