The Roof Assembly Ventilation Coalition (RAVC) participated in the development of the 2012 International Residential Code (IRC), published by the International Code Council (ICC). The RAVC proposed language aimed at adding clarity to the code, provide for balanced intake and exhaust for ventilated attics, and help ensure that attic ventilators work as intended. This language is also included in the 2015 IRC.
Sections 806.2 of the 2012 IRC and the 2015 IRC include:
“At least (Not less than) 40 percent and not more than 50 percent of the required ventilating area is provided by ventilators located in the upper portion of the attic or rafter space. Upper ventilators shall be located no more than 3 feet (914 mm) below the ridge or highest point of the space, measured vertically, with the balance of the required ventilation provided by eave or cornice vents. Where the location of wall or roof framing members conflicts with the installation of upper ventilators, installation more than 3 feet (914mm) below the ridge or highest point of the space shall be permitted.”
The code language also includes a requirement that ventilators be installed in accordance with the manufacturer’s installation instructions. With increased reliance on tested components, proper installation is just as important as proper design. Attic ventilation is a proven design method that helps the roof assembly manage moisture, heat, and enhances roof covering durability.
By proposing and supporting detailed code provisions addressing the balanced approach to intake and exhaust, the ARMA Asphalt Roofing Ventilation Task Force is taking the lead role in advancing ventilated attic assemblies.