APP Bitumen Modified - Page 4

7B.12 Steep Slope Requirements – Heat Welded Systems

7B.12.1 Heat welded APP and PAO roofing membranes can be applied on inclines up to 6" per foot (500 mm/m) when proper precautions are taken. On non-nailable decks, wood nailers must be used. Nailers act as insulation stops for the roof insulation and as a facility to back nail the membrane. On slopes up to 2 1/2 " per foot (208 mm/m), the roofing sheets may be installed either perpendicular or parallel to the roof incline.

7B.12.2 Non-Nailable Decks: On decks with a slope over 2 1/2 " per foot (208 mm/m), the roofing felts must be installed parallel to the incline and must be back nailed. Pressure-treated wood nailers shall be attached to the deck, run perpendicular to the incline, be capable of retaining the nails securing the roofing sheets, have the same thickness as the insulation, and be at least 3 1/2 " (89 mm) wide.  They should be securely attached to the deck with mechanical fasteners to resist a pullout force of 200 pounds (890 N). Wood nailers shall be provided at the ridge and at the following approximate intermediate points:

7B.12.3 Nail the modified bitumen cap sheet at the end lap across the width of the sheet, with the first nail spaced 3/4 " (19 mm) from the leading edge of the sheet, and the remaining nails spaced approximately 8 1/2 " (216 mm) o.c. The nails shall be staggered across the width of the nailer to reduce the risk of the sheet tearing along the nail line. Nails must have an integral 1" (25 mm) (min.) diameter cap. Where capped nails are not used, fasteners must be driven through caps having a 1" (25 mm) (min.) diameter. All nails are to be covered by the lap of the next sheet.

7B.12.4 Nailers must also be used around the roof perimeter, openings and penetrations, for nailing felts, gravel stops, roof fixtures and fascia systems.

7B.12.5 Nailable and Lightweight Concrete Decks: On decks with a slope over 2 1/2 " per foot (208 mm/m), the roofing felts must be installed parallel to the incline. Nail the end laps of the modified bitumen cap sheet across the width of the sheet on 8 1/2 " (216 mm) centers. All nails are to be covered by the lap of the next sheet.

7B.12.6 Steep Slope Requirements – Systems Incorporating Asphalt

7B.12.7 APP and PAO roofing membranes that incorporate asphalt adhered base/intermediate felts can be applied on inclines up to 3" per foot (250 mm/m) when proper precautions are taken. On non-nailable decks, wood nailers must be used. Nailers act as insulation stops for the roof insulation and as a facility to nail the membrane. On slopes up to 1/2 " per foot (41.6 mm/m), the roofing sheets may be installed either perpendicular or parallel to the roof incline.

7B.12.8 Non-Nailable Decks: On decks with a slope over 1/2 " per foot (41.6 mm/m), the roofing felts must be installed parallel to the incline and must be back nailed. Pressure-treated wood nailers shall be attached to the deck, run perpendicular to the incline, be capable of retaining the nails securing the roofing sheets, have the same thickness as the insulation, and be at least 3 1/2 " (89 mm) wide.  They should be securely attached to the deck with mechanical fasteners to resist a pullout force of 200 pounds (890 N). Wood nailers shall be provided at the ridge and at the following approximate intermediate points:

Nailers may also be laid out to conform to the roll length being used. For slopes between 1/2 " to 2" per foot (41.6 to 167 mm/m), nailers should be spaced to accommodate full-length modified bitumen rolls. For slopes between 2" to 3" per foot (167 to 250 mm/m), the nailers should be spaced to accommodate half-length rolls.

7B.12.9 Cut the modified bitumen cap sheet to conform to the nailer spacing. Nail the end lap across the width of the sheet, with the first nail spaced 3/4 " (19 mm) from the leading edge of the sheet, and the remaining nails spaced approximately 8 1/2 " (216 mm) o.c. The nails shall be staggered across the width of the nailer to reduce the risk of the sheet tearing along the nail line. Nails must have an integral 1" (25 mm) (min.) diameter cap. Where capped nails are not used, fasteners must be driven through caps having a 1" (25 mm) (min.) diameter. All nails are to be covered by the lap of the next sheet.

7B.12.10 Nailers must also be used around the roof perimeter, openings and penetrations, for nailing felts, gravel stops, roof fixtures and fascia systems.