Roof Attic Ventilation Requirement

Foot of ventilation for every 150 sq.

Roof attic ventilation requirement.

The following are the requirements taken directly from the irc. Intake vents located at the lowest part of the roof under the eaves allow cool. Code requirements the international building code. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca.

Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems. 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. The key to proper ventilation of your roof and attic is balance. Feet of attic space divided 50 50.

The majority of the requirements related to attic ventilation have not changed much from the previous editions. In cold climates the primary purpose of attic or roof ventilation is to maintain a cold roof temperature to control ice dams created by melting snow and to vent moisture that moves from the conditioned space to the attic ventilation acts to bypass the vapour barrier created by most roof. 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. 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.

Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. The roofing industry also has practical guide lines for attic ventilation. 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. Throughout the balance of this digest the terms attic and roof will and can be used interchangeably.

Typically building codes include minimum requirements applicable to attic ventilation. 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. You can also contact your local municipality to check on building code in your area. 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. Explore owens corning ventilation products.