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APP Modified Bitumen Specifications |
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7B.1 General Information
7B.1.1 This section provides application information, and outlines specifications currently available from Johns Manville (JM) Roofing
Systems, for APP (Atactic Polypropylene) and Classic (Polyalphaolephin-PAO) Modified Bitumen Roofing Products. APP modified bitumen
products may be installed by heat welding and in JM MBR® Cold Application Adhesive. The Classic Series of modified bitumen products is
unique in that it can be heat welded, cold applied or installed in hot asphalt. For hot asphalt applied Classic systems, refer to the application
guidelines in the SBS modified bitumen section of this manual (Section 7A.5 - 7A.13).
7B.1.2 All general information contained in this section and in the current JM Commercial/Industrial Roofing Systems Manual shall be
considered part of these specifications.
7B.1.3 Specifications are available for systems installed over insulation, nailable, non-nailable, and lightweight fill substrates. JM offers
systems that can be installed by heat welding or in JM MBR® Cold Application Adhesive.
7B.1.4 For heat weld application, all safety procedures must be reviewed prior to application. All contractors must understand, review
and adhere to the information contained in the following sources:
Johns Manville Safety Guidelines for Heat Weld Application
ARMA Guide to Torch Safety
ARMA Torch Safety Video
7B.1.5 JM does not recommend the use of traditional asphalt cut-back mastics under any APP or Classic modified bitumen product. The use
of cut-back mastics over the modified bitumen product (e.g., to strip in the edges of a base flashing) is acceptable. JM has developed two
adhesives – MBR Cold Application Cement, and MBR Utility Cement – that are compatible with all of the JM APP and Classic Modified
Bitumen Products. They should be used whenever a cold adhesive application is necessary or preferred.
7B.1.6 Each specification in this section is eligible to receive a JM Roofing System Guarantee. Refer to the information on guarantees in the
current JM Commercial/Industrial Roofing Systems Manual, or contact a JM representative for additional information.
7B.1.6.1 This manual clearly differentiates between requirements and recommendations. This manual has been written to assist the
specifier to develop a comprehensive bid package. The information is presented in an explanatory fashion rather than the authoritative,
instructive manner commonly utilized in construction specifications. When experience, technical knowledge, or established testing procedures
support a policy or position, it is clearly identified, (i.e., "JM requires" or "is not acceptable"). When the use of a particular product or practice
is desirable, the reference is stated as an opinion rather than an absolute fact, (i.e., "JM recommends" or JM suggests"). It is mandatory
that all requirements be complied with, however, it may not be necessary to follow all recommendations to qualify for a Guarantee.
7B.1.7 Drainage of water off any roof membrane is necessary to prolong the service life of the system. JM, therefore, has the following policy:
Drainage: Design and installation of the deck and/or membrane 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.
7B.1.8 Flashings: Refer to Section 8 of the current JM Commercial/ Industrial Roofing Systems Manual for APP and Classic Flashing
Specifications and Details. APP and Classic details will begin with the prefix "WFE".
7B.2 Membrane Substrate
7B.2.1 The surface on which the APP or Classic modified bitumen roofing membrane is to be applied should be one of the following JM
products: Nord Board, JM APP Base Sheet, Ventsulation Felt, GlasBase, PermaPly 28, or an approved structural substrate. GlasPly Premier
and GlasPly IV may be used in selected specifications. (See Roof Finder Index, page 7-42.) The surface must be clean, smooth, flat and dry.
7B.3 Roofing Over Non-Nailable Decks
7B.3.1 These specifications are for use over any type of structural deck which is not nailable, and which offers a suitable surface to receive the
roof. Poured and pre-cast concrete decks require priming with JM Concrete Primer prior to the application of hot asphalt.
7B.3.2 These specifications are also for use over JM roof insulations – Nord Board, Fesco Board, Tapered Fesco Board, Fesco Foam,
Tapered Fesco Foam, E’NRG’Y 2, Tapered E’NRG’Y 2, 1/2" Retro-Fit Board, and Fiber Glass Roof Insulation, or other insulations that
offer a suitable surface to receive the roof. For heat-weld application directly to the insulation, the top layer of insulation must be
Nord Board.
7B.3.3 These specifications are denoted by an "I" as the third character in the specification designation (e.g., 3CIN-W). See the "Roof Finder
Index" in this section for further information.
7B.4 Roofing Over Nailable Decks
7B.4.1 These specifications are for use over any type of structural deck (without roof insulation) which can receive and adequately retain nails
or other types of mechanical fasteners recommended by the deck manufacturer. Examples of such decks are wood and plywood. Certain
specifications are suitable for use over lightweight insulating concrete decks or over fills made of lightweight insulating concrete. Consult the
"Roof Decks" section of the current JM Commercial/Industrial Roofing Systems Manual, or contact a JM Technical Service Specialist for
approval of the lightweight concrete to be used.
