I'm trying to upgrade my ceiling electrical boxes for ceiling fans. The house is from 1935 and lord knows when the electrical work is from, but it's old.

Got up in the attic to get the old box out and this is what I found:

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So it's a quarter inch thick metal (iron?) bar running between the joists and attaching via a clamped metal threaded rod that comes through the center of the existing junction box.

From what I've read, my best guess is that the metal rod is likely nailed into the joists from below? So do I need to cut under the joists? Is that safe to do? Can I do it with hand tools or do I need to go out and buy a sawzall or something?

As for the box itself, once I get the bar out, do I just start chipping the plaster until it comes loose?

Thanks from a plaster newbie.

  • Just guessing but that box and install may be stronger than if you cut the metal bar out, then add blocking and then a new fan rated box that just connects to a 2x4 nailed between the existing rafters. Plus all that hammering may crack the heck out of the ceiling, just my opinion but sometimes old construction is much better than “listed” boxes of today. Just my opinion but I have remodeled quite a few Victorians (older than this) and currently live in a 1930 farm house, other than the actual wiring the hardware is superior to today’s for the most part.
    – Ed Beal
    Sep 29, 2019 at 1:16
  • Thanks @EdBeal! That might work for the larger 3.5" box, but there's also a 2" box that won't work for the fan.
    – GimpyBee
    Sep 29, 2019 at 1:20
  • 1
    can you remove just the 2" box and install the size you need on the same bracket? maybe visit an electrical supply store for a match.... you'd stll have to cut away some plaster but that support bar is great.
    – JACK
    Sep 29, 2019 at 1:37
  • @JACK Unfortunately, no. The box is attached to the support bar in a way that it can't be separately removed.
    – GimpyBee
    Sep 29, 2019 at 1:47
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    Lathe and plaster can be fragile, and a sawzall may vibrate it too much. A Dremel or similar with a metal cutting blade is much gentler.
    – kgc
    Sep 29, 2019 at 2:51

1 Answer 1


I'd be looking to cut around the perimeter of the box, isolating it from the ceiling and then. go to work on the steel once the vibrations from cutting it will not be transferred to the ceiling

An angle grinder will make short work of steel, but does produce lots of red-hot sparks that travel quite a distance before cooling. A hack-saw is slower, and can produce larger vibrations but will not produce sparks.

This will not be a quick job consider erecting a scaffold rather than working from a step-ladder.

  • 3
    Could do the same thing from the attic side. Use a plumbers heat guard to catch grindings. And leave behind any part of the bar embedded in the plaster.
    – DaveM
    Sep 29, 2019 at 12:13

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