There aren’t many instances when you would need to sand ceramic tiles. It’s a job that needs to be carefully done as it’s all too easy to remove the finish of the tile, which is part of its charm. About the only time you’d consider sanding ceramic tile would be if you were going to repaint it; sanding will help paint adhere to the surface. Under any other circumstances you’d remove the tiles and replace them.
Step 1 - Cleaning
Before starting to sand ceramic tiles, they have to be completely clean. Begin by using a cleaner on them with a soft scrubber if there are marks that won’t remove easily. If the tiles haven’t been cleaned for a long time this could involve plenty of work. Once all the marks are off the tile, wash with soap and water and leave them to dry.
Step 2 - Sanding
If there are areas you don’t want to sand you should use masking tape and cardboard to ensure they’re not accidentally sanded. Similarly, put masking tape at the edge of the tile area where it meets the wall. Put a drop cloth under the area you’ll be sanding to catch much of the dust; this will make the clean up easier when you finish.
Use an orbital sander and sandpaper with a fine grit. 220 grit is recommended to sand ceramic tiles. This will take the glaze off the tile but still leave the surface smooth. The sanding needs to be a slow and careful process. The trick is to ensure that all the glaze is removed but none of the finish. Just work on a small area at a time, cleaning it often to see what progress has been made. Don’t push too hard with the sander, let it do the work for you. If you miss some small areas you can go back over them later, moving the sander very lightly. Be prepared to change sanding discs frequently so the sandpaper can be most effective.
WARNING: You don't want to get ceramic particles in your lungs or eyes, so put on a respirator mask and safety glasses before you start sanding.
Step 3 - Checking
Whenever you stop to check progress, you need to clear the dust off the tiles. A tack cloth is the very best way to do this. It will allow you to see if there is glaze still left without dampening the tiles.
Step 4 - Washing
When you believe you’ve finished sanding the ceramic tiles you need to wash them down to take off the rest of the dust. Use soap and water and a sponge for this. Wash the grout areas too, as this is where dust will gather. Give the tiles ample time to dry before you inspect them again. If there are any tiny areas with glaze that you missed, you should sand the ceramic tile by hand to remove the last pieces of glaze. Again, don’t press too hard, and keep checking to be certain you’re not going beyond the glaze.