How To Fix Cracks In Concrete Floor. How to Repair Wide Concrete Cracks. The sealer will need something to grab onto to properly set.
Use a concrete epoxy to reseal the crack. Roughen the Edges of the Crack. For more information see How to Break Up Concrete.
If youre concrete floor has a hairline crack you wont need the sand to repair this one.
Use a concrete epoxy to reseal the crack. Sweep away any loose debris then vacuum the crack. Scoop the mortar into the crack or hole. A product like Rust-Oleum Concrete Patch is easy to use and works great at patching up cracks.