Roof Attic Vent Spacing

They should be divided equally between inlet and outlet vents and they can be used in any combination that will work with your roof s design.

Roof attic vent spacing.

Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. You can calculate attic ventilation requirements by determining the square footage of your attic floor its width times its length and compare that to the total required net free area nfa. As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space. Of vent for every 300 sq.

Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. This pk topic provides commonly accepted ventilation practices compatible with a decra roof system installation. In order to facilitate this exchange of warm and cool air the general rule of thumb suggests installing at least 1 sq. Before we explore how to ventilate an attic space it is prudent to understand how much ventilation is needed.

Proper attic area ventilation is an important performance consideration for a home or building with a steep slope roof. Typically building codes include minimum attic space ventilation requirements as well as the roofing industry weighing in on practical guidelines. What does the code require. According to the national roofing contractors association nrca a power vent with an airflow rate of 1 0 cubic foot per minute per square foot of attic space measured at the attic floor is generally considered to be equivalent to a 1 150 ventilation ratio.

Most building codes require a ratio of 1 150 ventilation space to attic floor space. Building codes vary. The key to proper ventilation of your roof and attic is balance.