Roof Attic Ventilation Requirements

Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca.

Roof attic ventilation requirements.

Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems. The roofing industry also has practical guide lines for attic ventilation. Enter square footage calculate or enter the square footage of the attic or area to be vented. Code requirements the international building code.

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. Most effective ventilation uses a ridge and soffit continuous ventilation system but even these designs can vary from roof to 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. The following are the requirements taken directly from the irc.

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

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 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. Foot of ventilation for every 150 sq. The key to proper ventilation of your roof and attic is balance.

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. Most building codes require a ratio of 1 150 ventilation space to attic floor space. The majority of the requirements related to attic ventilation have not changed much from the previous editions. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.

You can calculate attic ventilation requirements by determining the square footage of your attic.