Setting the New Tile You can set the replacement tile with either an adhesive ($5 per quart) or latex-fortified thinset mortar ($8 for a 50-lb. sack). Both products are applied with a notched trowel and work well for all types of tile. We used thinset. Why? Because we happened to have some on hand. Dump about two cups of thinset into a bucket and stir in about 1/3 cup of water for each 8-in. tile you're replacing. Mix to a smooth consistency, adding more water if necessary. Let the thinset stand, or slake, for about 10 minutes so all the water is absorbed. Spread a 1/4-in.-thick bed of mortar onto the subfloor with a 3-in.-wide drywall knife; be sure the entire area is covered. Next, rake out the mortar with a 1/4-in. notched trowel (photo 4). Set the new tile into the fresh mortar, center it in the space and tamp it down using a wood block and a hammer handle (photo 5). Be sure the tile is still centered, then let the mortar cure overnight. Mix powdered grout with water in a small container. Its strength and color are affected by too much or too little water, so follow package directions closely. Again, let the mixture stand a few minutes for full water absorption. Then stir the grout one more time and force it into the joints with a rubber float (photo 6); a large, dense sponge also works. Sweep the rubber float or sponge over each joint diagonally several times until the gaps are filled and level with the surrounding joints. Skim over the surface a final time to scrape up any excess grout. Let the grout cure until a hazy film dries on the surface of the tile. Lightly wipe the surface with a damp towel to remove this film (photo 7). After waiting a few hours, thoroughly buff the entire area you worked on with a clean, dry towel. You should avoid walking on the new tile for at least another 24 hours.