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Built-Up Roofing Specifications

Five Ply Smooth Surfaced Fiber Glass Built-Up Roof. For use over wood or other nailable decks on inclines of 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 (without insulation) which can receive and adequately retain nails or other types of mechanical fasteners that may be recommended by the deck manufacturer. Examples of such decks are wood and plywood. This specification is not for use directly over lightweight, insulating concrete decks.

Design and installation of the deck and/or 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 are not eligible to receive a JM Roofing Systems Guarantee.

Note: All general instructions contained in the current JM Commercial/Industrial Roofing Systems Manual should 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

Over wood board decks, one ply of sheathing paper must be used under the base felt and on top of the wood board deck.

Note: On roof decks with slopes up to 2" per foot (166.6 mm/m), the roofing felts may be installed either perpendicular or parallel to the roof incline. On slopes over 2" per foot (166.6 mm/m), refer to Paragraph 6.11 of this section for special requirements.

Using GlasBase, GlasBase Plus, PermaPly 28 or Ventsulation, start with a 12" (305 mm) width (a specific base sheet may be a condition of Guarantee). The following base sheet courses are to be applied full width, lapping the preceding felt 2" (51 mm) on the side laps and 4" (102 mm) on the end laps. Nail the side laps 9" (229 mm) o.c. Down the longitudinal center of each felt, place two rows of nails spaced approximately 11" (279 mm) apart, with the nails staggered on approximately 18" (457 mm) centers. Use nails or fasteners appropriate to the type of deck with 1" (25 mm) minimum diameter caps. For additional fastener information, refer to the Fastener Data in the "Roof Deck" section of the current JM Commercial/Industrial Roofing Systems Manual.

Using GlasPly Premier or GlasPly IV, apply a piece 9" (229 mm) wide, then over that, one 18" (457 mm) wide, then over that, one 27" (686 mm) wide. Over these 3 partial sheets, install a full width 36" (914 mm) piece. The following felts are to be applied full width, overlapping the preceding felts by 27 �" (699