I removed a rotten 4x4 post that was used for a fence. The concrete hole seems sound. I was thinking of putting a 2 3/8 metal pole in this 4x4 hole and then filling with concrete.

I am not sure if there would be enough new concrete around the metal post to make a secure fit.

If this works I will probably replace all the 4x4 wood posts with metal posts.

Any ideas or previous experience around this would be appreciated.

  • So are you saying you were able to pull the wood post out of the concrete? Is the concrete solid no breaks? If it is cracked or broken there would not be much new material to hold together. If it is solid a little extra Portland cement mixed with sand and wet enough to get it in the hole would work.
    – Ed Beal
    Mar 25, 2016 at 14:01
  • Yes. I would pull the wood post out of the concrete. So far I have pulled three out of the concrete leaving a 4x4 space in what looks like a good concrete base. I have not pulled out all the posts so I am sure there will be some that are cracked, if they are I can use your approach.
    – Badger2001
    Mar 25, 2016 at 14:10
  • I am not sure if it is cracked in 2 pieces if there would be enough strength but worth a try.cement made with sand is more of a mortar but this will be thin so it may work and it will bond to the original cement.
    – Ed Beal
    Mar 25, 2016 at 15:30

3 Answers 3


You'll have a hard time getting concrete into a 1" gap. You'll want to either enlarge the hole slightly or use a loose sand mix concrete, which will likely crack up, but should retain the post adequately.

  • Thats a great idea. If sand doesnt work it would easy to start over. The wholes are pretty deep, close to 2ft. Hopfully enough to hold.
    – Badger2001
    Mar 25, 2016 at 13:54
  • @Badger2001, just to make sure you got it, he's talking about a concrete mix made with sand rather than larger aggregate. Not just sand...
    – JPhi1618
    Mar 25, 2016 at 14:52
  • My original post mentioned plain sand. Sorry about the confusion.
    – isherwood
    Mar 25, 2016 at 16:00

What if you poor the concrete into the hole before inserting the post? Just wiggle it down? Seems like that would be easier than trying to poor concrete around the pole.

Curious to know the outcome of your project

  • This puts a great shearing force on the pole where it meets the concrete. post installers never recommend filling the pole with concrete.
    – JACK
    Jul 3, 2020 at 21:58

I would just clean up the hole and pour new concrete before setting the post. It's called floating. That way concrete gets inside as well as outside the pipe under ground. You can also adjust the height and not have to go as deep. 3' hole with only 2' of the post in the concrete for example.

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