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APP Modified Bitumen
Specifications |
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Specification
3CIS-W/3PIS-W |
Three Ply Heat Welded Modified Bitumen
Smooth 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
Materials per 100 sq. ft. (9.3 m2) of Roof Area |

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
applications 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 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.
For an identical copy of this specification, ask for RS-4349.