A prefabricated roof curb mounts onto a wood roof deck over wood blocking and roof insulation, maintaining an eight inch minimum height. The exhaust fan sits atop the curb with a foam-rubber gasket applied by the manufacturer and counterflashed by the fan skirt using typical two inch hex screws. A backdraft damper is anchored to the outward curb flange with four screws in the corners, ensuring power leads run inside the corner without interfering with damper operation. Roofing, flashing, and curb leveling are provided by the general contractor with a one and a half inch minimum clearance.
DAMPER FOAM-RUBBER GASKET APPLIED TO TOP OF FAN CURB BY MANUFACTURER COUNTERFLASH BY FAN SKIRT 2" HEX SCREW (TYP.) PREFABRICATED CURB BY MANUFACTURER ROOFING, FLASHING, & CURB LEVELING BY GC ROOF INSUL. WOOD BLOCK ROOF DECK CURB FLANGE OUT ANCHOR BACKDRAFT DAMPER TO CURB FLANGE OUT WITH 4 SCREWS IN CORNERS RUN POWER LEADS IN CORNER INSIDE CURB BY EC. (WIRING MUST NOT INTERFERE WITH OPERATION OF BDD) ROOF CURB EXHAUST FAN 8" MIN. 1 1 2 " MIN. DAMPER
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