4GNS. CSI 3-Part Specifications. Large file (>500kB).

Built-Up Roofing Specifications

Four 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.

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 an 18" (457 mm) width (the use of 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 12" (305 mm) wide, then over that, one 24" (610 mm) wide, then over both, a full width piece. The following felts are to be applied full width, overlapping the preceding felts by 24 2 /3" (627 mm) so that at least 3 plies of felt cover the base felt/substrate at all locations. Install each felt so that it is firmly and uniformly set, without voids, into the hot asphalt (within �25�F [�14�C] of the EVT) applied just before the felt at a nominal rate of 23 lbs. per square (1.1 kg/m²) over the entire surface.

Surfacing

Finish the entire membrane surface with a uniform application of the selected coating. Refer to Paragraph 6.9.3 of this section for more specific information regarding the particular coating. Pay particular attention to the installation directions printed on the label of the container for the chosen coating.

Asphalt

Asphalt should meet the requirements of ASTM D 312. JM Guarantees require the use of Trumbull asphalt or another JM Approved Asphalt. The Contractor must provide an Asphalt Confirmation Number (ACN) on projects which require a JM Guarantee. The ACN will indicate that the asphalt was registered with the approved asphalt source.

Check with a JM Technical Services Specialist for special asphalt requirements in hot climates.

For an identical copy of this specification, ask for RS-2034.