I needed to unmount a drywall ceiling diffuser to do a small fix. The diffuser is a "traditional" stainless still box mounted using two screws driven straight into the sheetrock. Unfortunately the builder did a pretty sloppy job and the opening was too large so the screws barely held. Unmounting them effectively cause the holes to crumble so now there is no easy way to screw them back in. Here's a photo of the opening (note how the screwholes have zero clearance from the opening sides):

Vent opening

I've tried to rotate the diffuser 90 deg. but it doesn't help as the opening is still large.

Question: can anyone suggest a trick (or a mounting kit, or a different kind of a diffuser) to put it back on the ceiling?


Nothing should ever be mounted just to the drywall. Whenever possible, everything should be mounted directly to the substructure (studs,blocking, etc.) When framing is not available hollow wall anchors should be used, but only in light duty applications. In the case of your vent I would suspect that two sides abut the rafters or joists. Locate them and try to run the mounting screws for your diffuser through the drywall into the structure. If this is not possible, mount some 1x material to the inside of your duct with sheet metal screws and secure the diffuser to that.


Using tin-snips and pliers, a small "L" shaped bracket could be fabricated from sheet metal with one leg fastened to the metal air box and the other leg receiving the screw holding the diffuser.

  • I guess, that would be my last resort measure. For now (being under pressure to deliver) I bore holes in the corners of the diffuser and drove screws through them diagonally (to avoid hitting the metal flanges of the box). – Alexander L. Belikoff Nov 15 '14 at 22:55

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