Roof Attic Ventilation Requirements

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

Roof attic ventilation requirements.

See the benefits of attic ventilation a new roof is more than just shingles. 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. Feet of attic space divided 50 50. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca.

If you don t know how your roof vents work or if you re unsure about your attic ventilation in general you should talk to a roof inspector about your current system and any inherent weaknesses that may be at. Code requirements the international building code. 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. Most building codes require a ratio of 1 150 ventilation space to attic floor space.

Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems. The key to proper ventilation of your roof and attic is balance. Intake vents located at the lowest part of the roof under the eaves allow cool. The majority of the requirements related to attic ventilation have not changed much from the previous editions.

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 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. Foot of ventilation for every 150 sq.

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 effective ventilation uses a ridge and soffit continuous ventilation system but even these designs can vary from roof to roof. 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 roofing industry also has practical guide lines for attic ventilation.

Typically building codes include minimum requirements applicable to attic ventilation.