enter image description hereI am working on replacing two outdoor ceiling fans. I need to replace the boxes with proper fan rated boxes.

The issue I’m having is this. The old boxes were screwed directly into what appears to be a 2x4 that I assume is mounted to the joists.

I basically have two options for mounting a new box. One of those old work tension bar boxes (my first choice) or a box that mounts on the joist.

The problem I have is that either way it looks like I need to cut the 2x4. I can only access the 2x4 through the hole so I’m not sure that I can get the entire thing out. If I can, I can use a tension bar mount. If I can’t, I’d have to do the bracket mount box directly to the joist.

Im just looking for any advice or opinions before I cut the 2x4. I really don’t want to tear the roof material up.

Thank you!

  • 2
    If the 2x4 is securely mounted to the joists, why not just screw the fan rated boxes into it?
    – JACK
    Commented Jun 7, 2022 at 17:30
  • 1
    The new box should be mountable on that cross-brace. For ceiling fans make sure it's a metal box, not plastic; or else the screws will rip out and the fan will fall over time. If using a tension bar then make sure it's rated for ceiling fans and not just light bulbs. lowes.com/pd/…
    – MonkeyZeus
    Commented Jun 7, 2022 at 17:54

1 Answer 1


Here is a closeup of the first ceiling fan box with mounting bar (this one happens to be a new work box) I found at "big blue":

annotated ceiling fan box
images courtesy of lowes.com. No endorsement intended or implied

The two red arrows point to the screws that mount it to the metal bar. Instead of using those holes to mount it to the bar, you could use them to mount it directly to the 2x4 in your ceiling.

Here's the first ceiling fan box that doesn't include a mounting bar.

another annotated box

The holes pointed to by the red arrows will accept screws for mounting it directly to the 2x4.

Make your choice, screw the box to the ceiling, be sure to knock out the proper knockouts (and use the proper bushings for the cables), and have a blast.

Tip for the future:

When removing wiring, it's best to not cut the wires short as appears to have been done here (red circle):

Snip of OPs original picture highlighting issues

Fortunately, you seem to have a reasonable amount of wire left, so you can strip back some of the cable sheath (along the green line) to expose more individual wire if you need to.

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