I have a 1954 built house with a cinder block crawlspace foundation with about a 1 1/2 foot clearance. I can squeeze in, but not easily. I'm in Cleveland, OH, so there is definitely a freeze-thaw cycle.

I was crawling around looking for the source of a moldy smell, and found that one of the cinder blocks under our renovated kitchen was shattered.

My question is what is the best way to fix this - various masons have suggested filling the space with hydraulic cement with maybe some bricks tossed in for good measure to fill the void.

My thought was to grind the broken block out and "butter" in a new block.

What is the best way?

Broken cinder block in crawlspace

  • If you remove what's left of that block, you may have bigger problems as what it's holding up (despite being half-missing, half of it is there) is no longer held up. So I'd go easy on the "remove and replace" uness you have figured out a way to hold up what's above while you do that.
    – Ecnerwal
    Sep 8, 2020 at 23:16

2 Answers 2


"Best" is what you can do in that tight space. If the cavity is filled with masonry it's probably fine. Ideally you'd replace the block with a like block and tuck-point the mortar in place. Might be easier said than done, though.

  • 1
    Turns out, the mason had to remove like 11 blocks - the concrete sidewalk on the outside had pressed into the foundation blocks causing the damage.
    – Eli
    Oct 21, 2020 at 19:30

Im not a pro by any means but the hydraulic cement suggestion would probably work just fine. I know hydraulic cement is often used to patch cracks in basement walls. Replacing with new block is ideal solution tho.

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