Roof Attic Ventilation Requirement

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

Roof attic ventilation requirement.

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. You can calculate attic ventilation requirements by determining the square footage of your attic. Explore owens corning ventilation products. Let owens corning roofing help you calculate exactly how much ventilation you will need for a healthy and balanced attic with our 4 step ventilation calculator.

Intake vents located at the lowest part of the roof under the eaves allow cool. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. Effective attic ventilation systems reduce damaging heat and moisture in your attic promote energy efficiency by helping to reduce the load on your air conditioner in the summer and also reduce the risk of ice dam formation on your roof.

Typically building codes include minimum requirements applicable to attic ventilation. Feet of attic space divided 50 50. The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction. 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.

The key to proper ventilation of your roof and attic is balance. Code requirements the international building code. See the benefits of attic ventilation a new roof is more than just shingles. The roofing industry also has practical guide lines for attic ventilation.

The following are the requirements taken directly from the irc. Foot of ventilation for every 150 sq. 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. You can also contact your local municipality to check on building code in your area.

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. Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems.