apply the roofing felts parallel to roof slope.
Delete the add-on requirement for applying felts to
barrel-type roofs when not applicable.
**************************************************************************
**************************************************************************
NOTE: When roof slope exceeds 1:12 (1 inch per
foot) specify backnailing. Coordinate with
insulation Section 07220 and nailer requirements
Section 06100 to allow for backnailing of the
membrane.
**************************************************************************
Ensure proper alignment of felts prior to installation. [Apply ply felts
shingle fashion perpendicular to slope of roof, including application on
areas of tapered insulation that change slope direction.][Apply ply felts
parallel to slope of roof [so that plies of felt extend from eave line on
one side of barrel-type roof and 450 mm (18 inches) over center line of the
crown of roof. Apply felts on other side in same manner, resulting in
twice normal amount of roofing felts and asphalt at crown].] Bucking or
backwater laps are prohibited. Apply felts in a continuous operation.
Provide starter sheets of felt to maintain the specified number of plies
throughout the roofing. Apply felts with side laps in accordance with the
material manufacturer's printed instructions for the number of plies to be
installed and in uniform alignment. Lap ends not less than 150 mm (6
inches) and stagger one meter (36 inches) minimum. The full width of each
ply shall be placed in hot bitumen immediately behind the bitumen
applicator. Plies shall be laid free of wrinkles, creases, ridges, or
fishmouths. Extend felts approximately 50 mm (2 inches) above top of cant
strips at vertical surfaces and to top of cant strips elsewhere. Trim
felts to a neat fit around vent pipes, roof drains, and other projections.
Avoid traffic on mopped surfaces when the bitumen is fluid and for a
minimum of one hour after ply application.
3.3.4.1
Hot-Mopping of Ply Felts
Bond plies to each other and to the [base sheets] [substrate] with hot
asphalt. Apply felts immediately following application of asphalt. Do not
work ahead with asphalt. At the instant felts come into contact with
asphalt, asphalt shall be completely fluid, with asphalt temperatures
within specified EVT range. Apply asphalt uniformly in a full, continuous
mopping and firmly bonding film. Apply asphalt at the rate of approximately
13 kg per 10 sq. meters (25 pounds per 100 square feet) plus or minus 25
percent. Application rate on the high end of the application range shall
be required when mopping directly to absorptive insulation substrates of
perlite and woodfiber. As felts are rolled into the hot asphalt,
immediately squeegee, roll or broom down to eliminate trapped air and to
provide tight, smooth laminations without wrinkles, buckles, kinks, or fish
mouths. Bitumen shall be visible beyond all edges of each ply as it is
being installed. Individual ply installation and the completed roof
membrane system shall be free of air pockets, felt delaminations, ridges,
creases, fishmouths, dry laps, or blisters. Do not lay felts dry or turn
back laps for mopping between plies.
[3.3.4.2
Backnailing of Ply Felts
**************************************************************************
NOTE: When roof slope exceeds 1:12 (1 inch per
foot) include the applicable paragraphs on
SECTION 07511
Page 25
Previous Page
