Roof Ventalation Requirements

Most building codes require a ratio of 1 150 ventilation space to attic floor space.

Roof ventalation requirements.

Attic ventilation requirements how many attic vents your roof needs industry standard for proper attic ventilation recommends for no vapor retarder type of attic insulation no paper plastic or aluminum layer between the attic floor and insulation layer 1 sq. Foot of ventilation for every 150 sq. R806 1 ventilation required enclosed attics and enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters shall have cross ventilation for each separate space by ventilating openings protected against the entrance of rain or snow. Roof vents choose one of the following products to meet the recommended exhaust nfva of 528 square inches.

You can calculate attic ventilation requirements by determining the square footage of your attic floor its width times its length and compare that to the total required net free area nfa. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. Ventilation openings having a least dimension larger than 1 4 inch 6 4 mm shall be provided with corrosion resistant wire cloth screening hardware cloth perforated vinyl or similar material with openings having a least dimension of 1 16 inch 1 6 mm minimum and 1 4 inch 6 4 mm maximum. The amount of space you devote to intake must be equal to the amount you allow for exhaust and these must be calculated according to the size of your attic and slope of your roof.

Ventsure 4 foot strip heat moisture ridge vent 27 lineal feet required.