All About Grout

Grout is forced into the spaces between tiles with a rubber tool called a float. The excess is wiped away with a wet sponge, leaving joints filled to just below the surface. After the grout cures rock-hard, the tiles are polished with a soft cloth to remove any "grout haze" left behind.

Epoxy grout is more expensive and more difficult to apply, but its durability makes it a good choice for high-traffic areas.

Choosing very different tile and grout colors can provide a striking contrast.

Worn and blackened, the grout on a kitchen counter and backsplash first gets a dose of powerful degreaser. "Never clean tile and grout with an oil-based soap," Parker says. "The wax in them builds up and stains grout."

A steam cleaner brings stains to the surface, where Parker and Thorp wipe them up. Homeowners can rent steam machines, but a stiff-bristle nylon brush and a degreaser also do the trick.

To remove failed grout, Parker uses a utility knife on thin, unsanded joints and a diamond-encrusted grout saw on sanded joints. "Just skimming over the old grout with new doesn't work," she says. "You have to remove at least half the depth of the old stuff before the new will bond to it."

The next step is to regrout the missing areas. Parker mixes up a batch and spreads it with a float. Most old grout is white, which makes color-matching relatively easy. In high-moisture areas, such as around faucets, and wherever tile abuts a dissimilar material, caulk is needed to keep out water.

When the grout has cured for several days, Parker returns to brush a penetrating sealer on the joints. "People are amazed after we've finished a job," she says. "One guy thought we had completely retiled his bathroom."