Filling Expansion Cracks

So my Pro is just about assembled, and I put leveling castors on all 4 legs. Not much of a coincidence, but all of a sudden I am noticing how deep the expansion cracks in my 2 car garage turned shop is… Does anyone have experience with filling those? I know they need to be able to expand/contract but it’s a pain to have to lift anything that I roll over them. CNC mill doesn’t move so it’s never been an issue until now but I die a little every time I subject the table to any kind of lateral forces rolling it over the crack…

Concrete crack sealer should work and allow a little movement I’d think.

I know how you feel. My welding cart is about 600lbs and I have about a 1/2" lip to roll over to get it back in the garage when I roll it outside to MIG weld. I’m not worried about the cart, it’s build like a tank, but I’m always worried I’ll have a caster fail and have something go tumbling.

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the best way to level out a concrete floor crack is to grind out a smooth “V” shape down about 1/2".
Then fill it all most to the top with a non-shrink grout…leave about 1/8" lower than surrounding edge.
If you can find a concrete bonding glue…it is like a milk like product to prep the v groove with…it will bond better.
Once the grout dries you can then place tape on each side of the filled crack and fill the remaining with a self leveling concrete caulking.

this is the best solution I have found. I live in Canada where we get shifting of concrete floors that have not been properly built…and this works well.
the grinding of the crack cleans out loose debris and allows a good surface prep…just like when you weld.
the non-shrink grout and bonding agent really help keep the space filled.
the caulking on top holds it all down, levels out the top, makes a smoother transition between surfaces.


Excellent insight- Thank you! To clarify though, it sounds like you are talking about repairing a crack or a fissure whereas I’m talking about the gaps that are built-in when the concrete is poured. From what you are saying though it sounds like maybe I could just prep and use self leveling concrete caulking without the bonding glue?

Yup…should work

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