An exhaust fan sits atop a prefabricated curb installed over a roof opening and roof membrane assembly. Rigid insulation and a cant strip transition the roof plane to the curb, sealed with flashing and counterflashing. The curb is secured using a typical 2 by 2 by one-quarter inch steel angle spanning at least two flutes, fastened with three-eighths inch diameter through-bolts with nuts, washers, and four total burr threads left after tightening at each corner. Lag bolts with one inch penetration secure the unit into a wood sleeper on each side. An exhaust duct connects to the fan through a flexible connection and a backdraft damper.
FLEXIBLE CONNECTION BACKDRAFT DAMPER EXHAUST DUCT ROOF OPENING ROOF MEMBRANE PREFAB CURB RIGID INSULATION CANT STRIP FLASH AND COUNTERFLASH ROOF TYP. ANGLE 2 x 2 x 1/4" (2 FLUTES MIN) USE 3/8"∅ THRU-BOLT TO WASHER (1 AT EA. CORNER) ANGLE BELOW W/NUT & 4 TOTAL BURR THREADS AFTER TIGHTENING NUT (TYP) NOTICE: 1. SEE STRUCTURAL DRAWINGS FOR ROOF PENETRATION DETAIL. 2. SEE ARCHITECTURAL DRAWINGS FOR WATERPROOFING. (4) |"~ LAG BOLTS 1\" PENETRATION INTO WOOD SLEEPER (1 EACH SIDE) EXHAUST FAN
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