I bought an LED house number online. The instruction asks me to

  1. insert machine screws without head (grub screw, threaded rod) into the four machine screw holes on the back the LED box
  2. drill holes in the wall using 1/5" bit (I intend to try my 3/16" stucco bits, because I've never seen 1/5" drill bits)
  3. fill the holes with silicone caulk
  4. push the light box into the holes

This seems very unconventional. I was expecting to receive mounting plates that I can screw into the wall, not something like this.

So my question: Is this a valid way to mount something outdoors? Does it work on stucco (assuming I'll use stucco bits)? If not, what are my options?

The provided instructions

  • 1
    I think I would try silicone caulk, though.
    – Huesmann
    Jun 29, 2023 at 12:55
  • 'Use a 1/5" bit' ... lol ... overly literal metric conversion there. 3/16" or 7/32" would be a much more sensible conversion. I'd guess the threaded rod is M4 (or maybe M3).
    – brhans
    Jun 29, 2023 at 14:18

1 Answer 1


The headless screws form "pins" that go into the caulked holes you drilled.

This is a valid method.

Just make sure you drill the holes square so the number sits straight.

Edit, based on second comment:

If you want to be able to remove it then I would do the following:

  1. make a wood, or plastic whatever, plinth that the number gets mounted on using screws that go through the plinth to secure the numbers.

  2. mount the plinth to the wall with suitable, like brass or stainless, screws.

That way you can replace the plinth or the number in the future.

  • Agreed, this sounds legit. Also use plenty of caulk so the holes are sealed for sure.
    – KMJ
    Jun 29, 2023 at 6:01
  • Thanks. I acknowledge that the holes would have to be square and in precise location. Otherwise the pins wouldn’t even fit. Quick follow up: once the caulk cures, how tight would the box be fastened to the wall? How would I remove it if I need to in the distant future?
    – Haozhun
    Jun 29, 2023 at 7:04
  • 1
    The box will be perfectly tight and sound, as long as the pins are far enough in. (I’d want a good inch.) Removal is just a prybar. Also, I’d oversize the holes a tiny bit to allow you to level the light perfectly. Plenty of masking tape or stucco tape (or a stud leaned up against it) will hold it in place while the silicone sets. Jun 29, 2023 at 13:27

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