Roof Venting Requirements

Measure the length and width of the attic floor space to be ventilated.

Roof venting 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. When exhausted directly outside. Building codes vary. Ft of net free venting.

Roof vents choose one of the following products to meet the recommended exhaust nfva of 528 square inches. According to their requirements you should have 1 square foot of attic ventilation per 300 sq ft of attic floor space. N a the exception to this rule is when using a whole house fan that ducts directly to the outside of your home. Of vent for every 300 sq.

The key to proper ventilation of your roof and attic is balance. Most building codes require a ratio of 1 150 ventilation space to attic floor space. Before we explore how to ventilate an attic space it is prudent to understand how much ventilation is needed. Theinternational building code 2012 edition ibc 2012 requires enclosed attics and enclosed rafter spaces formed where ceilings are applied directly to the underside of roof framing to have cross ventilation for each separate space.

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. There should also be a 50 50 balance of attic venting and roof venting. Ft or more of unobstructed roof venting also known at 2 7 sq. Section r806 roof ventilation r806 1 ventilation required enclosed attics and enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters shall have cross ventilation for each separate space by ventilating openings protected against the entrance of rain or snow.

If your roof is 1200 sq ft soffit floor space you will need 4 sq feet of roof ventilation. In order to facilitate this exchange of warm and cool air the general rule of thumb suggests installing at least 1 sq. Ventilation can be accomplished using various products and techniques. Ventsure 4 foot strip heat moisture ridge vent 27 lineal feet required.