06-28-08 Building Codes Appeals Board minutes

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* 1 Bulk shipments of materials shall be accompanied by the same information issued in the form of a certificate or on a bill oflad- ing by the manufacturer. SECTION R90S REQUIREMENTS FOR ROOF COVERINGS R90S.1 Roof covering application. Roof coverings shall be applied in accordance with the applicable provisions of this I section and the manufacturer's installation instructions. Unless otherwise specified in this section, roof coverings shall be installed to resist the component and cladding loads specified in Table R30 1.2(2), adjusted for height and exposure in accor- dance with Table R30l.2(3). R90S.2 Asphalt shingles. The installation of asphalt shingles shall comply with the provisions of this section. R90S.2.1 Sheathing requirements. Asphalt shingles shall be fastened to solidly sheathed decks. R90S.2.2 Slope. Asphalt shingles shall be used only on roof slopes of two units vertical in 12 units horizontal (2: 12) or greater. For roof slopes from two units vertical in 12 units horizontal (2:12) up to four units vertical in 12 units hori- zontal (4: 12), double underlayment application is required in accordance with Section R905.2.7. R90S.2.3 UnderlaymenL Unless otherwise noted, required underlayment shall conform to ASTM D 226 Type I, ASTM D 4869 Type I, or ASTM D 6757. Self-adhering polymer modified bitumen sheet shall comply with ASTM D 1970. R90S.2.4 Asphalt shingles. Asphalt shingles shall have self-seal strips or be interlocking, and comply with ASTM D 225 or D 3462. I R90S.2.4.1 Wind resistance of asphalt shingles. Asphalt shingles shall be installed in accordance with Sec- tion R905.2.6. Shingles classified using ASTM D 3161 are acceptable for use in wind zones less than 110 mph (49 m/s). Shingles classified using ASTMD 3161, Class F, are acceptable for use in all cases where special fastening is required. R90S.2.S Fasteners. Fasteners for asphalt shingles shall be galvanized steel, stainless steel, aluminum or copper roof- ing nails, minimum 12 gage [0.105 inch (3 nun)] shank with a minimum 3fs-inch (10 nun) diameter head, ASTMF 1667, of a length to penetrate through the roofing materials and a minimum OP/4 inch (19 nun) into the roof sheathing. Where the r-oof sheathing is less than 3/4 inch (19 nun) thick, the fas- teners shall penetrate through the sheathing. Fasteners shall comply with ASTM F 1667. R90S.2.6 Attachment. Asphalt shingles shall have the min- imum number of fasteners required by the manufacturer. For normal application, asphalt shingles shall be secured to the roof with not less than four fasteners per strip shingle or two fasteners per individual shingle. Where the roof slope exceeds 20 units vertical in 12 units horizontal (167 percent slope), special methods offastening are required. For roofs located where the basic wind speed per Figure R30 1.].( -+) is 2006 INTERNATIONAL RESIDENTiAL CODE@ ROOF ASSEMBLIES ~ 110 mph (49 m/s) or higher, special methods of fastening are required. Special fastening methods shall be tested in accordance with ASTM D 3161, Class F. Asphalt shingle I wrappers shall bear a label indicating compliance with ASTM D 3161, Class F. .. R90S.2.7 Underlayment application.' For roof slopes from two units vertical in 12 units horizontal (17 -percent slope), up to four units vertical in 12 units horizontal (33-percent slope), underlayment shall be two layers applied in the following manner. Apply a 19-inch (483 nun) strip of underlayment felt _ parallel to and starting at the eaves, fastened sufficiently to hold in place. Starting at the eave, apply 36-inch-wide (914 nun) sheets of underlayment, overlapping successive sheets 19 inches (483 nun), and fastened sufficiently to hold in place. Distortions in the underlayment shall not interfere with I the ability of the shingles to seal. For roof slopes of four units vertical in 12 units horizontal (33-percent slope) or greater, underlayment shall be one layer applied in the following manner. Underlayment shall be applied shingle fashion, par- allel to and starting from the eave and lapped 2 inches (51 nun), fastened sufficiently to hold in place. Distortions in the I underlayment shall not interfere with the ability of the shin- gles to seal. End laps shall be offset by 6 feet (1829 nun). R90S.2.7.1 Ice barrier. In areas where there has been a I history of ice forming along the eaves causing a backup of water as designated in Table R30 1.2(1), an ice barrier that consists of a least two layers of underlayment cemented together or of a self-adhering polymer modi- fied bitumen sheet, shall be used in lieu of normal underlayment and extend from the lowest edges of all I roof surfaces to a point at least 24 inches (610 nun) inside the exterior wall line of the building. Exception: Detached accessory structures that con- tain no conditioned floor area. R90S.2.7.2 Underlayment and high wind. Underlay- ment applied in areas subject to high winds [above 110 mph (49 m/s) per Figure R301.2(4)] shall be applied with corrosion-resistant fasteners in accordance with manu- facturer's installation instructions. Fasteners are to be applied along the overlap not farther apart than 36 inches (914 nun) on center. R90S.2.8 Flashing. Flashing for asphalt shingles shall com- ply with this section. R90S.2.8.1 Base and cap flashing. Base and cap flashing shall be installed in accordance with manufacturer's instal- lation instructions. Base flashing shall be of either corro- sion-resistant metal of minimum nominal 0.019-inch (0.5 nun) thickness or mineral surface roll roofing weighing a minimum of 77 pounds per 100 square feet (4 kglm2). Cap flashing shall be corrosion-resistant metal of minimum nominal 0.019-inch (0.5 nun) thickness. R90S.2.8.2 Valleys. Valley linings shall be installed in accordance with the manufacturer's installation instruc- tions before applying shingles. Valley linings of the fol- lowing types shall be permitted: 1. For open valley (valley lining exposed) lined with metal, the valley lining shall be at least 24 inches 291