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APP Modified
Bitumen
Specifications |
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Specification
1CIS-W/1PIS-W |
One 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 |

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 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 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.