How to Regrout on Top of Grout

Grout is a type of cement that sits between the tiles on your floor or wall, forming one solid surface with the tiles. Over time, grout can crack and crumble, requiring you to regrout the area.

Digging out the old grout to add new material is a physically challenging process, so you don’t want to do more than you have to. As long as you can dig out enough of the old grout so the new grout has some space to set, you can grout over what’s left of the old.

  1. Scrape your grout saw along the damaged portions of the grout, digging out all that’s loose or cracked and taking it all the way to solid surrounding grout. Make sure that any areas where you dig out the grout go down at least ¼ inch.

  2. Suck out the broken-up grout with a vacuum hose.

  3. Combine grout mix and water in a bucket in the ratio stated on the grout package. Mix vigorously with your putty knife, making enough wet grout to cover the whole extracted section of the grout lines.

  4. Allow the grout sit in the bucket for about 10 minutes. Stir it again.

  5. Apply the grout over the extracted grout lines with your grout float, scraping the grout diagonally over the lines with the long end of the float while pressing the grout into the spaces.

  6. Let the grout sit for 10 minutes. Use a damp sponge to wipe up the excess.