granule application in areas of bitumen bleed out.
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Underlying applied membrane shall be inspected and repaired free of damage,
holes, puncture, gouges, abrasions, and any other defects, and free of
moisture, loose materials, debris, sediments, dust, and any other
conditions required by the membrane manufacturer prior to cap sheet
installation. Provide cleaning and artificial drying with heated blowers
or torches as necessary to ensure clean, dry surface prior to cap sheet
application. When delays in cap sheet installation may have occurred, do
not apply cap sheet if underlying materials have been exposed to rain or
frozen precipitation within the previous 24 hours. Unroll cap sheet
membrane and allow to relax a minimum of 30 minutes prior to installation
and as otherwise recommended by the membrane manufacturer. Apply cap sheet
in same direction as the underlying felt plies. Align cap membrane and
apply with minimum 75 mm (3 inch) side laps and minimum 150 mm (6 inch) end
laps and as otherwise required by membrane manufacturer. Cap sheet shall
be set in hot asphalt. Cap sheet may be torch applied with approval of the
Contracting Officer and written approval of the felt membrane manufacturer,
and as recommended by the modified bitumen membrane manufacturer. Cut at a
45 degree angle across selvage edge of cap membrane to be overlapped in end
lap areas prior to applying overlapping cap membrane. [Apply matching
granules in any areas of bitumen bleed out while the bitumen is still hot].
Minimize traffic on newly installed cap sheet membrane.
[3.3.11.1
Backnailing of Cap Sheet Membrane
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NOTE: Include this paragraph for roof slopes
greater than or equal to 1:6 (2 inches per foot).
Coordinate with insulation Section 07220 and nailer
requirements Section 06100 to allow for backnailing
of the membrane.
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Unless otherwise recommended by the roof membrane manufacturer and approved
by the Contracting Officer, install the modified bitumen cap sheet to
provide for end laps at nailer locations. Nail the modified bitumen cap
sheet at the end lap area across the width of the sheet. Nail within 25 mm
(1 inch) of each edge of the sheet and at 200 mm to 215 mm (8 to 8-1/2
inches) on center across the width of the sheet in a staggered fashion.
Nails shall have 25 mm (1 inch) diameter metal cap or be nailed through 25
mm (1 inch) diameter caps. Cover nails by overlapping adjacent upslope
sheet at the end lap area.
]]3.3.12
Correction of Deficiencies
Where any form of deficiency is found, additional measures shall be taken
as deemed necessary by the Contracting Officer to determine the extent of
the deficiency and corrective actions shall be as directed by the
Contracting Officer. [Where interply moppings are too light, apply
additional two plies of felt in full moppings of asphalt. Apply with 100
mm (4 inch) side and end laps. Where free water, skips, excessive voids,
dry laps, disbonding or any form of delamination are discovered between the
plies, remove and rebuild affected area. Correction of inadequate number
of plies, improper lap widths, or non-uniform or excessive asphalt mopping
shall be as directed by the Contracting Officer.] Where insulation is
found to be wet, remove insulation and provide new built-up roofing and
insulation.
SECTION 07511
Page 29
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