Roof Attic Ventilation Requirements

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.

Roof attic ventilation requirements.

Feet of attic space divided 50 50. 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. Intake vents located at the lowest part of the roof under the eaves allow cool. Most effective ventilation uses a ridge and soffit continuous ventilation system but even these designs can vary from roof to roof.

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. Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems. See the benefits of attic ventilation a new roof is more than just shingles. 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.

The following are the requirements taken directly from the irc. 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. Enter square footage calculate or enter the square footage of the attic or area to be vented. The roofing industry also has practical guide lines for attic ventilation.

The majority of the requirements related to attic ventilation have not changed much from the previous editions. Foot of ventilation for every 150 sq. You can calculate attic ventilation requirements by determining the square footage of your attic. 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. Code requirements the international building code. 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.

Typically building codes include minimum requirements applicable to attic ventilation.