We bought a house last year that has a broken chunk of concrete near the joint where the garage floor meets the asphalt driveway.

I noticed on the other end of the garage (2nd photo) there's a gap between the asphalt and the concrete and a sinkhole is forming underneath.

I know the previous owners installed new blacktop right before the sold the home. I am thinking the foundation blocks below the front of the garage weren't filled in and there's a lot of erosion under the garage apron. Maybe the collapsed section broke because there wasn't anything below it?

On to my questions...

  1. How can I fix the collapsed portion? We're hoping to have the garage floor resurfaced this summer so I want to make sure it's fixed correctly.
  2. If there is a big sinkhole below the joint, how should I fix that?

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2 Answers 2


Cut a straight line parallel to the garage with a concrete saw and remove the concrete.

Put in gravel, compact it down, add an inch of sand or stone dust and then put down a few rows of pavers.

If it happens again, you can just re-install the pavers.

This picture is way overkill but to give you the idea (but they didn't measure to make the pavers fit...they had to cut some!):

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The piece that moves has to be jack hammered out and removed. Get rid of that and assess. The new concrete can fill any voids when that is gone or you add non-compressible fill (3/4 crush gravel is good). MN has an 80" frost depth, how old is the house / do you feel like the builder installed frost protection for shallow foundations? I feel like your gut instinct is correct and the foundation at that front garage door area is insufficient. Also you don't want a crack that allows liquid water under your driveway/garage and allows frost heave.

Why do you think there is a foundation wall under that portion of the apron. Does the rest of the garage wall sit on CMU?

  • > Why do you think there is a foundation wall under that portion of the apron. Does the rest of the garage wall sit on CMU? I don't know whether it does. I did some searches and sort of assumed that there was from what I was reading.
    – jessegavin
    Apr 2, 2022 at 16:33
  • Garage foundations commonly run under the front of the slab, under the door opening, in order to keep the height of the slab under the door consistent.
    – isherwood
    Apr 27, 2023 at 14:11

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