2009 Irc Roof Ventilation Requirements

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.

2009 irc roof ventilation requirements.

Typically building codes include minimum requirements applicable to attic ventilation. Where the roof sheathing is less than 3 4 inch 19 mm thick the. Fasteners for asphalt shingles shall be galvanized stainless steel aluminum or copper roofing nails minimum 12 gage 0 105 inch 2 67 mm shank with a minimum 3 8 inch diameter 9 5 mm head of a length to penetrate through the roofing materials and a minimum of 3 4 inch 19 1 mm into the roof sheathing. Where the roof sheathing is less than 3 4 inch 19 1 mm thick the nails.

Code requirements the international building code. The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction. January 2009 code for residential buildings that creates minimum regulations for one and two family dwellings of three stories or less. The ventilation openings shall have a least dimension of 1 16 inch 1 6 mm minimum and 1 4 inch 6 4 mm maximum.

U factor and total ua res check approach. Fasteners for asphalt shingles shall be galvanized steel stainless steel aluminum or copper roofing nails minimum 12 gage 0 105 inch 3 mm shank with a minimum 3 8 inch 10 mm diameter head astm f 1667 of a length to penetrate through the roofing materials and a minimum of 3 4 inch 19 mm into the roof sheathing. The roofing industry also has practical guide lines for attic ventilation. Vented attics shall have a minimum net free ventilation area at least 1 300 of the area of the vented space.

Between half and two thirds of the provided ventilation shall be installed at the eaves. Open vent pipes that extend through a roof shall be terminated at least 6 inches 152 mm above the roof or 6 inches 152 mm above the anticipated snow accumulation whichever is greater except that where a roof is to be used for any purpose other than weather protection the vent extension shall be run at least 7 feet 2134 mm above the roof. It brings together all building plumbing mechanical fuel gas energy and electrical provisions for one and two family residences. Ventilation openings shall have a least dimension of 1 16 inch 1 6 mm minimum and 1 4 inch 6 4 mm maximum.

Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems. For impact rated fenestration complying with section r301 2 1 2 of the irc or section 1608 1 2 of the ibc maximum u factor shall be 0 75 in zone 2 and 0 65 in zone 3.