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APP Modified
Bitumen
Specifications |
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Specification
3CIN-W/3PIN-W |
Three Ply Heat Welded Modified Bitumen Mineral Surfaced Roofing
System. For use over Johns Manville JM) insulation, approved
decks, or other approved insulations on inclines up to 6" per foot
(500 mm/m).
For Regions 1, 2 and 3

General
This specification is for use over any type of approved structural deck
which is not nailable and which provides a suitable surface to receive
the roof. Poured and pre-cast concrete decks require priming with
JM Concrete Primer prior to application of the first heat welded
modified bitumen ply. This specification is not to be used over
poured or pre-cast gypsum decks, lightweight insulating concrete
decks or fills without JM insulation.
This specification is also for use over JM roof insulations, or other
approved roof insulations which are not nailable and which provide a
suitable surface to receive the roof. Specific written approval is
required for any roof insulation that is not supplied by JM. Insulation
shall be installed in accordance with the appropriate JM Insulation
Specification detailed in the JM Commercial/Industrial Roofing
Systems Manual. This specification can also be used in certain
reroofing situations. Refer to the "Reroofing" section of the JM
Commercial/Industrial Roofing Systems Manual. For heat weld
application directly to the insulation, the top layer of insulation
must be JM Nord Board.
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
Heat weld a 19 3/4" (502 mm) wide piece of one of the intermediate
plies listed. Over that, apply a full width piece. The remaining plies
are to be applied full width, overlapping the previous plies by 21 3/4"
(553 mm), so that at least 2 plies cover the substrate at all locations.

Heat weld a full width piece of one of the cap sheets listed.
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.
Heat weld all plies so that they are firmly and uniformly set. All laps
must be rolled with a 3" (76 mm) rounded edge roller. A 1/8" to 3/8"
(3 mm - 10 mm) bleedout of APP compound shall be visible at the
edge of all seams. All laps must be checked for good adhesion.
Preparation of the 6" (152 mm) end lap requires scuffing away all
loose granules. Heat and embed all remaining granules. Apply heat
to the roll being seamed while making sure both have a good
compound flow to adhere the two surfaces. End laps must be
checked for proper 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
No additional surfacing is required.
For an identical copy of this specification, ask for RS-4345.