We just had a crawlspace inspection (unrelated to this topic) and the inspector found one of our support posts was loose enough to be wiggled back and forth. It wasn’t quite touching the concrete pier. Since the house is built (2016, west coast) with all wood support posts on concrete piers, what’s the best approach to stabilizing this one loose post? There’s maybe 1/4” space at most between the post and the pier, so not much room to work with.

We’d like to DIY if that’s advisable, but don’t want to take chances doing it wrong. We’re also tapped out financially due to numerous household repair and maintenance projects lately.

Is it advisable to try and shim it up with a cut to fit pressure treated wood, or do we need to replace the whole post? The post itself is in good condition,it’s just loose.

Any advice?

Picture of loose support post

  • 1
    Welcome to Home Improvement. Please edit your question to include a close up picture showing the post, pier and where the post meets the floor above. Then provide a similar shot showing one of the other posts that is firmly attached to the floor. This will help those of us who can't see what you see come up with a workable solution. It may be something that can be shimmed with wood, or have the post base adjusted or replaced, but without seeing it, it's just guessing from this side of the internet...
    – FreeMan
    Nov 16, 2022 at 12:19
  • I don’t currently have more photos, will need to go back down into the crawlspace and snap more. The posts are set atop concrete piers with some sort of grit paper (similar to composite roof shingles) between the post and the pier. Apparently, this is acceptable per code in our area. We do have a significant amount of piers/posts, probably 20? This was what the builder used in our subdivision and the city signed off on. I’m understanding now that it’s not ideal.
    – Shannon T
    Nov 16, 2022 at 21:31

2 Answers 2


Normally a couple of wooden shingles driven in would do, but since it's the concrete facing end you'll need to cut similar wedges from pressure-treated wood (or possibly soak some shingles in wood preservative - which would be easier.)

Start from opposite sides with the pointy ends in and overlapping, drive alternately until tight. You'll want to use a block of wood between the hammer or mallet and the shingle/wedge so that it drives, rather than being smashed by the hammer.


I would use a bottle jack to raise the beam slightly as you put in a new post or shim the existing one. You could drive in shims, but chances are the beam is a bit low of where it really should be. Shims are unlikely to actually lift the beam as may be needed.

  1. With someone observing above, jack the beam up just a little bit. You can assume that it has settled anyway, and this will bring it back to level and get you room to fit a shim under the post. You'll have to judge how much by how easily it moves, and you could pull a carpenter's string to assess straightness of the beam and floor framing overall. Aim for about 1/16" higher than the final position.

  2. Now measure the gap under the beam or post. Be sure the tape measure is plumb (vertical), and measure several places to account for unevenness in the concrete or beam face.

  3. Cut the new post or shim to size. For a new post, square your measurement around all faces and cut full-depth with a circular saw, then finish with a hand saw or reciprocating saw.

  4. Set the shim or new post in place. Plumb and flush all components, and ease the jack down. Friction will hold things in place.

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