I discovered today that there are some holes cut in the wooden frames (located near the ceiling of the basement). I suspect that mice come through these holes. The holes are of regular shape (trapezium); it is definitely man made, and I also found holes of the same shape in other parts of the frame at similar relative locations (near a rebar). What are these holes for and is it safe to block these holes with steel wool and caulk? enter image description here

  • 1
    Perhaps someone had a thought to run LAN or coaxial through this at some point, but declined? If you decide to plug, foam filler can also work.
    – JaredH
    Jan 27, 2021 at 14:18
  • The problem is if you want to mouse-proof, you are asking the wrong question/looking in the wrong spot. You need to find out where they come in from the outside. Once they're in the building, any holes you plug, they will just find other spots to come through. Feb 26, 2021 at 14:45
  • What are we looking at through that hole? Can we get a bigger/more zoomed in shot? I would expect such a notch on a joist (to allow for sliding in place around an anchor bolt), but not on a sill plate.
    – TylerH
    Feb 26, 2021 at 15:52

1 Answer 1


I have no idea what the hole is for but feel free to plug them.

  • 3
    I'm pretty sure you're correct, but this feels a bit like it's glossing over something...
    – FreeMan
    Jan 27, 2021 at 14:00

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