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Roof Insulations |
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Specification 1M1A
Two Layers Mechanically
Attached/Asphalt Attached |
Mechanically Attached
Apply the bottom layer of approved JM roof insulation with long joints continuous. End
joints should be staggered so they are offset at least 12" (305 mm) from the end joints in
adjacent rows. Use an approved mechanical fastener of sufficient length to penetrate
through or into the deck as required by the specific fastener. Fasteners should be placed
in the pattern for the approval desired but never closer than 6" (152 mm) from either edge
of the insulation board. On steel decks, the edges of the insulation board that runs parallel
to the deck rib must be solidly supported by the ribs. Fasteners are to be driven through
the appropriate insulation plates. Care should be taken not to overdrive or underdrive the
fastener. Overdriving the fastener will cause the insulation plate to "cup" and can result in
inadequate performance. Underdriving can cause the insulation to be loose from the
deck.
Firmly set the top layer of approved JM roof insulation, long joints continuous and short
joints staggered, into a full width of mopping of hot asphalt (within ±25°F [±14°C] of the
EVT). The bitumen should be applied at a nominal rate of 30 Ibs. per square (1.46 kg/m 2
). All joints must be offset a minimum of 6" (152 mm) between top and bottom layers of
insulation.
Apply only as much insulation as can be covered by a complete roof membrane in the
same day. Do not leave insulation exposed to the weather.
See Specification 1M for proper fastening of insulation into other deck substrates.
