Duct support

[dallas]

How can one support air duct about 15 ft. down from the roof. Will trapeze type supports work or is the distance too great? The duct will run above existing lay-in ceiling. Any recommendations? Thanks

 

[fredb]

Hello

Trapeze type supports should work fine. Spacing should be 10 feet max. for rectangular duct, 12 feet max. for round duct. Supports should be spaced about 3 feet apart where a heavy grille or damper is suspended. If you are in an earthquake zone you should determine if lateral and/or cross bracing is required to satisfy codes.