Grout is a thin mortar used for filling spaces between tiles [source: Merriam Webster]. Grout does not strengthen or hold the tiles in any way. Rather, it prevents water from getting between the tiles and gives an aesthetically pleasing finished look to the tiled area. When replacing your grout, you can either try to buy a color that matches the color of the tiles, buy a contrasting color, or even buy a neutral gray color [source: Kolle]. Here we will tell you how to repair grouting that is in bad condition.

Materials needed:

Here's what to do:

  1. Mix a solution of even parts water and vinegar.
  2. Clean the grout with this solution.
  3. Remove the loose grout with the grout saw. Be careful not to chip the tiles.
  4. Dampen the grooves with water, using a sponge. Don't make the grooves too wet.
  5. Mix the grout with water, as per the instructions on the package. Spread the grout over the joints using the grout trowel, completely filling them up.
  6. Wipe away any excess grout with a damp sponge, before it dries. Make sure you remove any grout from the surface of the tiles. Rinse the sponge when it gets too full of grout and then continue removing the excess grout.
  7. Allow the grout to dry.
  8. Buff all the tiles with a rag [source: Lowes].