Mice are coming in an opening between my concrete foundation and the rim joist.

I bought some steel wool to stuff into the holes and some 1/4 " steel mesh to block access.

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From within my crawlspace, I can access the holes but there's no even surface to place the mesh. Also, the hole is large such that it's easy to accidentally push the steel wool through.

Here's a picture of the hole from within the crawlspace (you can see the yard outside): view from crawlspace

To address both problems I'd like to place the mesh on the outside where the foundation and rim joist are flush. This way the wool can squeeze against the foundation, rim joist, AND the mesh for a secure fit. The steel mesh would cover the cracks so it would be secured to the rim joist and the outer concrete foundation wall.

Here's a view from the outside, underneath the porch. view from outside


Question 1:

Is this a good idea? Should I be trying something else? I did some research and noticed people combining steel wool and foam spray but I have a feeling the hole is too large for that.

Question 2:

If this is a good idea, how do I secure the steel mesh to the concrete? I shouldn't be drilling into the concrete because this may cause cracks right?

  • steel wool pot scrubbers that are filled with soap are a better deterrent than plain steel wool
    – jsotola
    May 21, 2023 at 4:49
  • Ah interesting, I can give that a shot @jsotola thanks! Even if those get a good grip, I'd still like to also place the mesh somewhere for an extra layer of defence.
    – Daniel
    May 21, 2023 at 4:56

1 Answer 1


Not convinced that you need to fasten the mesh to the concrete, rodents wont' 'lift' it up to get under. If you staple the mesh to the timber and as long as it lies flat onto the concrete (maybe bend the mesh a little so stapling forces it against the concrete) I don't foresee a problem.

If it refuses to play ball and leaves small gaps, you could always use a tube style adhesive/sealer to fill the small gaps (just go through the mesh, onto the concrete). I can't name brands as it varies all over the world, but search for a construction adhesive and you'll find something suitable. Silicone would work in a pinch, it's just to fill the gap and if it sticks as well, that's just a bonus (builder here with over 30 years fighting little furry things...)

  • That's great advice, it never occurred to me I can just use the natural stiffness of the mesh. I'll give that shot! Thanks!
    – Daniel
    May 21, 2023 at 16:13

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