backnailing. For insulated roofs, delete the second
bracketed option. For uninsulated roofs on nailable
decks, delete the first bracketed option and include
only the second.
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Unless otherwise recommended by the roof membrane manufacturer and approved
by the Contracting Officer, [provide minimum 90 mm (3-1/2 inch) wide
nailing strips matching insulation thickness and applied perpendicular to
roof slope for backnailing of roof membrane. Space nailing strips as
recommended by the membrane manufacturer, but not exceeding 5 meters (16
feet) on center unless approved otherwise by the Contracting Officer.
Coordinate the nailer installation with insulation requirements. As the
felt plies are installed, nail each ply 25 mm (1 inch) from the leading
edge at each nailer line.] [fasten each felt ply 25 mm (1 inch) from the
leading edge and spaced at maximum 5 m (15 feet) on center along the
leading edge.] Fasteners shall have 25 mm (1 inch) diameter metal cap or
be fastened through 25 mm (1 inch) diameter caps. Set fasteners firm and
flush without puncturing felt ply. Conceal fasteners with succeeding plies
of felt.
]3.3.4.3
Valleys and Ridges
Felt plies shall continue across valleys and ridges and terminate
approximately 12 inches from the valley or ridge. Exposed lap shall
terminate on a line approximately 12 inches from, and parallel to the
valley or ridge. Two plies of roofing felt 9 inch wide bottom ply, and 12
inch wide top ply, shall be successively mopped-in over each felt line of
termination.
3.3.5
Membrane Flashing
Provide two plies of modified bitumen membrane strip flashing and sheet
flashing in the angles formed where the roof deck abuts walls, curbs,
ventilators, pipes, and other vertical surfaces, and where necessary to
make the work watertight. Top ply of flashing shall be granule-surfaced
modified bitumen membrane. Install flashing after plies of roof membrane
felt have been applied but before aggregate surfacing is applied. Cut at a
45 degree angle across terminating end lap area of cap membrane prior to
applying adjacent overlapping cap membrane. Press flashing into place to
ensure full adhesion and avoid bridging. Ensure full lap seal in all lap
areas. Mechanically fasten top edge of base flashing 150 mm (6 inches) on
center through minimum 25 mm (1 inch) diameter tin caps with fasteners of
sufficient length to embed minimum one inch into attachment substrate.[
Apply matching granules in any areas of asphalt bleed out while the asphalt
is still hot.] Apply membrane liner over top of exposed nailers and
blocking and to overlap top edge of base flashing installation at curbs,
parapet walls, expansion joints and as otherwise indicated to serve as
waterproof lining under sheet metal flashing components. Metal flashing
are specified under Section 07600 FLASHING AND SHEET METAL.
3.3.5.1
Strip Flashing
Set primed flanges of sheet metal flashings to be incorporated into roofing
system in a uniform coating of asphalt roof cement not less than 1/16 inch
thick applied over the ply felts. Strip-in with one layer of smooth
surface modified bitumen membrane and cap with granule-surfaced modified
bitumen membrane. Set strip flashing in hot asphalt or cement to the tops
of the flanges, roofing membrane, and to each other. Use coatings of
SECTION 07511
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