On our property there is a fairly old garage that hasn't been tended to in some time. The floor is cracked and buckling. What are possible fixes for this?

I've attached a photo. If you look closely you can see that it has heaved up sharply through the patches.enter image description here

  • 4
    Let Godzilla out of the basement. He knows that Mothra is coming to destroy you, and he only want to help! More seriously, that amount of movement indicates a problem below (possibly not radioactive movie monster related) and the fix is unlikely to be easy or cheap, and will probably involve removing the damaged concrete to resolve the issue.
    – Ecnerwal
    Jul 19, 2017 at 17:55
  • I'm actually not willing to rule out Mothra at this point. My assumption has always been that there isn't an easy fix, but this is well out of my wheelhouse and I am hoping someone has a clever idea.
    – CJ F
    Jul 19, 2017 at 18:05
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    If you are in a freeze-thaw zone this could be responsible for your problem. Garages are usually concrete poured slab-on-grade and the footings are only required to be 12" deep. That said, I would call a reputable concrete contractor for input. They may have an economical fix for you.
    – ArchonOSX
    Jul 19, 2017 at 18:14
  • If it's well out of your wheelhouse, the clever idea is to call in a professional.
    – mmathis
    Jul 19, 2017 at 18:15
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    Buckling could be tree roots. Is there a tree fairly close to the garage? The only easy way for a home owner to decide....break out a chunk and see whats under it. Compact the ground and add gravel and sand to level it, compact it some more. Then clean out the crack with a dickie (concrete saw) and widen it a bit. Once you have prepped it all, get a load of concrete delivered, or start mixing bags and filling the holes in.
    – Jeff Cates
    Jul 20, 2017 at 0:26

1 Answer 1


a) Grind concrete until it is flat, then grout the remaining cracks. You'll have an even thinner but flat floor, problem will likely re-occur.


b) Pour thicker new concrete over the top, with steel mesh, to make a more resilient replacement floor. Might still crack, as base is suspect.


c) Cut out & remove the failed floor, inspect the base to determine true cause, remove failed layers, install proper bedding, insulation layer & damp proof membrane, re-pour concrete.

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