Replacing a ceramic countertop tile is an easy do-it-yourself project. Most of the tools needed are ones that you probably have already or can be easily obtained at your local hardware store or home improvement center.
Step 1: Remove the Broken Tile
Most do-it-yourselfers feel that removing the broken tile without damaging or cracking the other tiles is the most difficult part of the project. The task can be a bit daunting, but take some safety measures, and things will go well. First, put on your goggles to protect your eyes from flying chips, and also put on your work gloves. Pieces of broken tile can be extremely sharp and can easily damage your vision or cut you severely. Place duct tape on the edges of all the tiles surrounding the one you are replacing. This will help to cushion and protect them in case the hammer or chisel slips.
Use the box knife to score the grout all the way around the broken tile. Then, use the hammer to hit the tile a couple of times to crack it more. Pick up all the broken pieces and discard. Don't use plastic trash bags, as they will cut through the bag. Instead, discard the pieces in an old cardboard box. Use the putty knife or scraper to scrape away any stubborn tile pieces and remaining adhesive and grout. Vacuum the area to remove any dust and tiny pieces of tiles.
Step 2: Installing New Tile
Make sure the tile fits into the opening you have created. If the area is too small, scrape away all the grout around the adjacent tiles. Put some tile adhesive into the open area and make groves in it with the tip of your putty knife. Place more adhesive on the back of the new tile and push it into the opening, wiggling it a bit to force out some adhesive and remove air bubbles. Wipe away any extra adhesive before it has time to dry, as it's almost impossible to remove once it's dry.
Apply grout to the area between the new tile and the old ones, and use spacers to maintain a straight line. Clean away extra grout before it dries. Use your wet sponge to do this, wringing it out in clean water frequently. Don't push so hard that you remove the grout you just applied. Grout left on tile will look cloudy, so use this as a guideline to determine whether you've cleaned the area properly.
Step 3: Finishing the Job
After the grout has dried, you should seal the new grout. If you haven't sealed the countertop grout in the past year, you should re-do the entire countertop at this time. Keeping the grout sealed will keep the grout from staining and discoloring over time. It also hardens it more and gives it a protective coating that helps keep it from chipping away. Apply the sealer with a paint brush per manufacturers instructions and also observe the manufacturers drying time recommendations for the job.