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APP Modified
Bitumen
Specifications |
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Specification
3CLS-W/3PLS-W |
Three Ply Heat Welded Modified Bitumen
Smooth Surfaced Roofing System. For use
over approved lightweight insulating fill
decks on inclines up to 3" per foot (250
mm/m).
For Regions 1*, 2 and 3 |
General
This specification is for use over any type of approved lightweight
insulating fill deck (without insulation) which can receive and
adequately retain mechanical fasteners that may be recommended
by the deck manufacturer.
Examples of these decks are lightweight insulating concrete, either
cellular-type or aggregate-type. Ventsulation venting base felt is
recommended over any wet fill deck, and may be required as a
condition of guarantee. JM also recommends the use of FP-10
One-Way Roof Vents over some types of wet fill decks.
* In Region 1, contact a JM Technical Service Specialist for written
approval when using this specification over lightweight insulating
concrete.
Design and installation of the deck and/or roof substrate must
result in the roof draining freely, to outlets numerous enough
and so located as to remove water promptly and completely.
Areas where water ponds for more than 24 hours are
unacceptable and will not be eligible for a JM Roofing System
Guarantee.
Note: This specification is also for use with JM PAO (Classic)
products. All general instructions contained in the current JM
Commercial/Industrial Roofing Systems Manual shall be considered
part of this specification.
Flashings
Flashing details can be found in the "Bituminous Flashings" section
of the JM Commercial/Industrial Roofing Systems Manual.
Application
Using one of the base plies listed, start with a piece 26 1/4" (665
mm) wide. The remaining plies are to be applied full width with 3" (76
mm) side and 4" (102 mm) end laps over the preceding sheets.
Using an approved light-weight insulating fill fastener, nail the laps at
9" (229 mm) centers, and down the longitudinal center of each felt ply,
place two rows of nails, with the rows spaced approximately 11" (279
mm) apart, and nails staggered on approximately 18" (457 mm)
centers. Use nails or fasteners appropriate to the type of deck, with
1" (25 mm) minimum diameter caps. For additional fastener
information, refer to the fastener data in the "Roof Decks" section of
the current JM Commercial/Industrial Roofing Systems Manual.
Over the fastened base ply, heat weld a half width 19 3/4" (502 mm)
piece of one of the intermediate plies listed with 4" (102 mm) side
and 6" (152 mm) end laps. The remaining plies are to be full width, in
the same manner, with 4" (102 mm) side and 6" (152 mm) end laps
over the preced-ing sheet.
Heat weld a full width piece of one of the cap sheets listed so that it is
firmly and uniformly set. Subsequent sheets are to be applied in the
same manner, with 4" (102 mm) side and 6" (152 mm) end laps over
the preceding sheets. All laps must be rolled with a 3" (76 mm)
rounded edge roller. A 1/8" to 3/8" (3 mm to 10 mm) bleedout of APP
compound shall be visible at the edge of all seams. All laps must be
checked for good adhesion.
Application of JM APP/PAO Modified Bitumen Products may
require the use of an open flame propane torch. Improper use
of these materials and application equipment can result in
severe burns, and/or other physical injury, as well as damage
to property. In order to prevent these situations the mechanic
must install the materials using the techniques recommended
by JM and those found in "A Guide to Safety: Torch-On
Modified Bitumens" available from the Asphalt Roofing
Manufacturers Association. These techniques have been
endorsed by the National Roofing Contractors Association
and the United Union of Roofers, Waterproofers and Allied
Workers.
For special precautions for heat weld application of JM Classic
(PAO) products, refer to Paragraph 7B.6.6.
For cold weather application techniques, refer to Paragraph 7B.14.
Steep Slope Requirements
Special procedures are required on inclines over 2 1/2" per foot (208
mm/m). Refer to Paragraph 7B.12.
Surfacing
Smooth surfaced membranes must be coated with a JM approved
coating. The coating chosen will depend on aesthetics and any fire
rating or Code approval required.
Note: When using metric and English sized sheets in the same
system, care must be taken to avoid lap over lap configurations.
For an identical copy of this specification, ask for RS-4352.
