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APP Modified Bitumen Specifications |
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7B.4.2 These specifications are denoted by an "N" or an "L" as the third character in the specification designation (e.g., 3CNN-W or
3PLN-W). See the "Roof Finder Index" in this section for further information.
7B.4.3 Over wood board decks, one ply of sheathing paper must be used under the base felt, next to the deck. Sheathing paper is not
required on plywood decks.
7B.4.4 All of the specifications in this section require the use of a nailable base felt. Use nails or fasteners appropriate to the type of deck.
See fastener data in the "Roof Decks" section of the current JM Commercial/Industrial Roofing Systems Manual.
7B.5 General Guidelines for Application of Materials
7B.5.1 The proper application of roofing materials is as important to the satisfactory performance of the roofing system as the materials
themselves. JM strongly recommends the following guidelines for the application of APP and Classic modified bitumen roofing materials be
followed. Always follow all recommended safety procedures when applying any heat welded product.
A. |
Never use wet or damaged materials. |
B. |
Never apply any roofing materials during rain or snow, or to wet or damp surfaces. Moisture trapped
within the roofing system may cause severe damage to the roofing membrane, insulation and deck. |
C. |
Take special care when applying any APP or Classic modified bitumen in cold weather (below 40°F
[4.5°C]). All rolls must be stored on end in a heated trailer or building. Only rolls needed for immediate
application should be exposed to ambient conditions. |
D. |
Never throw or drop rolls of APP in cold weather; sudden shocks can cause cracking of the APP
coating asphalt. |
E. |
Do not double stack (with or without pallets) in cold weather. |
F. |
Remove all packaging from product and dispose of properly. Be sure to have the appropriate side of
the product in position to be heat welded (polyolefin side down). |
G. |
APP modified bitumen sheets shall be rolled or scrolled into place as they are heat welded. |
H. |
Do not use traditional cut-back asphalt cements under APP modified bitumen products. The use of
these mastics over the top of APP products is acceptable, however the MBR cement products are
preferred. |
I. |
Install the entire roofing system at one time. Phased construction may result in blisters due to
entrapment of moisture, as well as poor adhesion due to dust or foreign materials that have collected
on the exposed felts of an incomplete roofing system. |
J. |
All smooth APP surfaced products must be coated with a JM approved coating. Acceptable roof
coatings for APP systems may be found in the built-up roofing section 6.9. |
K. |
Always comply with published safety procedures for all products being used. See the
"Introduction" section of the current JM Commercial/Industrial Roofing Systems Manual,
MSDS, and container labels for health and safety recommendations. |
7B.6 Roofing Products
7B.6.1 JM manufactures different products for a variety of roofing needs: membranes, flashing, venting and vapor retarders.
7B.6.2 Roofing felts are furnished in rolls consisting typically of one square. Flashing materials are sold in square feet.
7B.6.3 A fiber glass base sheet (JM APP Base Sheet, Ventsulation, GlasBase, or PermaPly 28) is required as a minimum first ply under all
Classic systems.
7B.6.4 JM APP Base Sheet, Vensulation, GlasBase, or PermaPly 28 are acceptable base plies in all JM APP and Classic systems. Note:
For applications over lightweight insulating concrete, a Vensulation Felt is recommended. There should be a minimum of one vent for every
1000 sq. ft. (93 m2)of roof area.
7B.6.5 The only roof insulation to which a JM APP product may be directly heat welded is Nord Board. JM APP membranes may only be
directly applied to Nord Board insulation. All other insulations require the use of a base ply mechanically fastened, hot mopped or cold applied
over the insulation. For insulation application instructions, refer to Section 9 of this manual.
7B.6.6 Special Precautions for Heat Weld Application of JM Classic (PAO) Products: Special care must be taken when applying
Classic products in ambient temperatures above 60°F (16°C). Heat welding these products requires an experienced applicator. The heat
welding device should be used to warm the surface to which the Classic product will be adhered, to reheat portions of the roll, and to melt the
modified bitumen on the back of the membrane which will be used to adhere the membrane. The area of the roll where the modified bitumen
is being melted is most critical; do not overheat.
7B.6.7 For more information on these products, refer to the "Products" section of the current JM Commercial/Industrial Roofing Systems
Manual.
7B.7 Heat Weld Application
7B.7.1 The surface over which the APP membrane is to be installed must be firm, dry, smooth, flat and free of debris and loose material. All
surfaces must be designed and installed in accordance with manufacturer’s, industry and acceptable association standards.
7B.7.2 Drainage: Design and installation of the deck and/or the substrate must result in the roof draining freely and 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.7.3 Roofing shall commence at the lowest point of the roof deck with laps installed so that water flows over and not against the lap. Align
the roll in the course to be followed and unroll completely. Then reroll both ends to the middle of the roll (scrolling). Using the heat welding
apparatus, apply the heat to the surface of the coiled portion of the roll until the surface reaches the proper application
