Roof Vent Per Square Foot

Based on your 1100 sq.

Roof vent per square foot.

Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. If your attic floor has a vapor barrier you will need one square foot of nfa per every 300 square feet of attic floor area half of that will be intake half for exhaust. Spray on roof with a spray on roof polyurethane solution is evenly applied for as little as 30 per square acrylic for 60 per square or the premium option of silicon spray averages 85 per square or more. So the ridge ventilation has exceeded the minimum requirement.

Standard ridge vent produces 18 square inches of ventilating area per lineal foot. This formula is traditionally used for static roof vents which are rated for net free area in terms of square inches. As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space. They should be divided equally between inlet and outlet vents and they can be used in any combination that will work with your roof s design.

Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space. Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge. The federal housing administration recommends 1 square foot of attic ventilation for every 150 square feet of attic space. Building codes typically echo the administration s guidelines.

This means that for every 300 square feet of enclosed attic space 1 square foot of ventilation is required with half at the upper portion exhaust vents and half in the lower portion intake vents. Nine hundred square inches equals 6 25 square feet. And this guideline you ll need a minimum of. Near ridge of the roof.

1 square foot of ventilation for every 300 square feet of space for pitched roofs with vapor barriers 1 square foot of ventilation for every 150 square feet of space no vapor barrier and for some municipalities in hot climates. Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge. If there is no vapor barrier double it to one square foot of nfa for every 150 square feet of attic floor space half for intake half for exhaust.