Steps:1. Remove any loose tiles, and cut along caulk lines and remove old caulk using a utility knife. Also scrape away old material from around the drain using a putty knife (figure A).
2. Mix up a solution of one part bleach to three parts water in a bucket, then scrub the joints using an old toothbrush. This will kill any remaining mold and mildew.
3. Dry the area completely with a clean towel.
4. Cut the tip of a tube of caulk so the bead is the same size as the joints you have to fill. Run a continuous, even bead of caulk along the joints (figure B).
5. Clear away excess caulk using your finger and a wet towel.
6. Clean old grout off the sides of loose tiles using a grout saw (figure C).
7. Put on rubber gloves and apply a liberal amount of adhesive to the back of the tile (figure D).
8. Replace the tile and give it a bit of a twist to force adhesive into an even layer behind the tile. Repeat process to replace all lose tiles. Wipe of excess adhesive with a paper towel.
9. Clean out old grout between other tiles with a grout saw. Mix up a batch of fresh grout according to directions.
10. Apply new grout using a grout float. Hold the float at a 45-degree angle and fill joints (figure E). Don't worry about being messy, just wipe away the excess grout with a damp sponge. Let the grout set up for about 20 minutes.
11. Buff away haze with a soft, clean cloth. Mist the grout with a water bottle each day for about a week so it cures properly.