Usually metal boxes are attached to vertical beams ("studs") in the wall. I have an opening in a lath & plaster wall with a horizontal beam just about 1/2"-1" underneath the opening. I cannot attach it directly to this beam. There is no stud closeby. I was thinking of drilling two holes through the metal box, then adding a custom piece of wood as a spacer between box and beam and screwing the two screws with an angled screw driver through the spacer into the beam from the inside of the box:

enter image description here

Is this acceptable?

A couple of notes:

  1. It is often proposed to increase the size of the hole. Since this is lath & plaster I really want to avoid this and stick with the current opening.
  2. Once fixed and screwed in place, I plan to fill the gaps with plaster of Paris
  3. I cannot use the this old work box because the hole is already too wide

For reference, this is how it currently looks like with a plastic old work box. You can see how bent the box is already because some plaster broke off during the stiff wire pulls, so the flanges are not flush on wood/plaster between top/bottom. There is so much tension currently (and the #12 wires don't help here) that I am worried this is not a future proof install (not even to mention, it's not a neat one).

enter image description here

  • Are you removing the plastic box because it is slightly deformed, or is the pic just an example of what you have as a wall?
    – RMDman
    Nov 15, 2023 at 22:14
  • I am removing the plastic box because it is deformed and I have concerns the plastic ears will endure for long time under so much tension. Since I am finishing this up currently, I might as well re-do it nicer. So yes, the picture shows the actual hole in question.
    – divB
    Nov 15, 2023 at 22:15
  • It's your home, but those plastic boxes have been in use for decades. I never have encountered one that failed. After all what else is being done other than insert and remove a plug.
    – RMDman
    Nov 15, 2023 at 22:18
  • It actually looks better on the picture than it really is ;-) But in any case, it's more my sense of "perfectionism". You are right, it'll probably be fine. Also, I was just replacing 100 years old K&T in my house and it was crazy how strong everything was installed (steel boxes double fixed into the framing, wires with strong studs). This would be good for another 100 years. Contrasting this to the bent plastic box with the flimsy ears it's hard to believe it will survive longer than ten years ;-)
    – divB
    Nov 15, 2023 at 22:33

1 Answer 1


That looks like a good plan to me. The only real issue is to make sure the box doesn't move under normal use. But with a decent shim and screws through to the beam you should be fine.

  • 1
    Actually, now that I think about it, I am planning to screw in the screws at an angle so I can use a normal screw deriver (or ratchet) which would get me much better torque than the angled one. I will still make sure that the screw is long enough to be deep in the beam. I will also pre-drill a hole through the spacer. Does this change your answer?
    – divB
    Nov 15, 2023 at 22:29
  • 1
    No change. Good plan. Nov 15, 2023 at 22:32
  • 1
    I think that the only problem here will be that the OP will need to drive the red screws diagonally, which isn't a huge problem in itself. If the thing was being installed without the wall, s/he coud of course remove the top of the box and screw vertically, then replace the top.
    – Huesmann
    Nov 16, 2023 at 17:01
  • @Huesmann That's the beauty of metal boxes. With plastic boxes anything outside the original design parameters of where screws should go, etc. can easily lead to cracks and replacement of the box. With steel boxes this is easy stuff. Nov 16, 2023 at 17:05

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