Roof Ventilation Requirements

The majority of the requirements related to attic ventilation have not changed much from the previous editions.

Roof ventilation requirements.

The following are the requirements taken directly from the irc. 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. The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction. 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.

Foot of ventilation for every 150 sq. You can also contact your local municipality to check on building code in your area. Feet of attic space divided 50 50 between the inlets and outlets. Most building codes require a ratio of 1 150 ventilation space to attic floor space.

Measure the length and width of the attic floor space to be ventilated.