Bathroom fan - attach to joist or strapping?

[PAB]

Was wondering if you might have any ideas on this one.

I added 1x4 strapping to my ceiling after having put up the guts of the bathroom fan, which I had attached to the joists. I've included a couple pictures. Since the joists were not level prior to installing drywall, I did the strapping.

The strapping (and shims) make the bottom of the guts of the ceiling fan approximately 1" above the bottom of the strapping.

I'd prefer not to attach the ceiling fan to the 1x4 as they are not as sturdy as the joists. The ceiling fan is a Panasonic fv-0811-rqc1.

Any suggestions on how to handle this?

Thank you!

 

[wwhitney]

Looking at the instructions, the issue, as I understand it, is that the "flex-z-fast" bracket that holds the fan and connects to the joists is designed to connect pretty close to the bottom of the joists. So if you just dropped the bracket 3/4" +/- to account for the strapping, the bracket screws would be too close to the bottom edge of the joist.?

Then how wide is the clear joist bay? The instructions show a 10-7/8" square opening in the ceiling. Do you have room to install 2x blocking along the bottom of the joists on each side, with the blocking bottom aligned with the strapping bottom, so that you can solidly secure the bracket to the blocking instead of the joists? That would obviously take up 3" of joist bay width.

Otherwise, you could consider fabricating a square sheet metal collar, with an L-shaped cross section, where one leg secures to the bottom of the joists and seasl to the fan enclosure, with the other leg extending the intake down to almost the bottom face of the drywall.

Cheers, Wayne

 

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[PAB]

Thanks so much Wayne for your reply! I think your idea of using 2x4s along the joists (parallel with the joists but slightly lower so they are aligned with the bottom of the strapping) may work. Didn't think of that option - will let you know if i run into any issues so that you can help me with the other option of sheet metal - no need right now b/c i have a good feeling about the 2x4s.
Thanks again.