more, apply felts parallel to roof slope. Include
requirements for applying felts to barrel-type roofs
only when applicable.
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[[Fully adhere ][Spot adhere ]base sheets in accordance with membrane
manufacturer's printed instructions. [Spot adhesion shall be with hot
asphalt applied in 300 mm (12 inch) diameter spots installed in two
staggered rows, centered 300 mm (12 inches) in from edge of the base
sheet.] Roll and broom in the base sheet to ensure full contract with the
hot asphalt application.] [On nailable substrates, mechanically fasten
base sheet in conformance with specified wind resistance requirements and
membrane manufacturer's printed instructions, and to include increased
fastening frequency in corner and perimeter areas. Drive fasteners flush
with no dishing or cupping of fastener plate. Where applicable, base sheet
may be mechanically fastened in conjunction with insulation to the
substrate, in accordance with membrane manufacturers printed instructions.]
Apply sheets in a continuous operation. Apply sheets with side laps at a
minimum of 50 mm (2 inches) unless greater side lap is recommended by the
manufacturer's standard written application instructions. Provide end laps
of not less than 150 mm (6 inches) and staggered a minimum of 1 meter (36
inches). Apply sheets [at right angles to the roof slope so that the
direction of water flow is over and not against the laps] [parallel to the
roof slope] [so that plies of sheets extend from eave line on one side of
the barrel-type roof and 450 mm (18 inches) over the center line of the
crown of the roof. Apply sheets on the other side in the same manner,
resulting in twice the normal amount of roofing sheets and asphalt at the
crown]. Extend base sheets approximately 50 mm (2 inches) above the top of
cant strips at vertical surfaces and to the top of cant strips elsewhere.
Trim base sheet to a neat fit around vent pipes, roof drains, and other
projections through the roof. Application shall be free of ridges,
wrinkles, and buckles.
[3.3.3.1
Ventilating Base Sheets
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NOTE: Include this paragraph in conjunction with
applicable portions of the above paragraph when
ventilating base sheets are specified in paragraph
entitled "Description of Roof Membrane System."
Where rigid board roof insulation is a component of
the roof system, ventilating base sheets should be
specified in the roof insulation section 07220.
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Apply ventilating base sheet material recommended by the roof membrane
manufacturer. Extend sheets over roof cants, up vertical surfaces, and
terminate under cap flashing; at roof edges terminate sheets under outside
edge of perimeter edge nailers or under gravel stop. [Top mop perforated
ventilating base sheet with a full, continuous mopping of hot asphalt.]
]]3.3.4
Ply Felts
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NOTE: Apply roofing felts at right angles to the
roof slope, except that on insulated roofs where
surface-applied wood nailers (insulation stops) have
been applied running at right angles to roof slope
and on decks sloped 1:6 (1/2 inch per foot) or more,
SECTION 07511
Page 24
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