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3GNS. CSI 3-Part Specifications. Large file (>500kB).
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Built-Up Roofing Specifications |
Specification 3GNS. |
For Regions 2 and 3
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. FlashingsFlashing details can be found in the "Bituminous Flashings" section of the
JM Commercial/Industrial Roofing Systems Manual. ApplicationOver 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 GlasPly Premier or GlasPly IV, apply a piece 18" (457 mm) wide, then
over that, a full width piece. The following felts are to be applied full width overlapping the preceding felts by 19" (483 mm) so that at least 2 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. SurfacingFinish 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. AsphaltAsphalt 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.