No matter how carefully your tiles have been fixed, sooner or later it’s inevitable that one or more of them will be cracked or chipped. Rather than replace the whole installation, though, you can just replace the damaged tile, as long as you had the foresight to keep some spares when the initial tiling was done. (You did, didn’t you?)
First of all, scrape out the grout from around the damaged tile, preferably using a grout rake – they’re cheap and readily available from any good DIY supplier. Removing the grout reduces the chances of damaging the surrounding tiles in the next stage, and you’ll need to remove it anyway so that you can apply fresh grout when you come to press the new tile into place.
Now take a cold chisel and chip out the old tile, working from the middle. Don’t be tempted to work from the outside, and above all don’t be tempted to prise out the old tile from the edge – you’ll most likely damage the tile next to it.
Having done that, remove the tile adhesive from the wall or floor the tile was stuck to, using a vacuum cleaner to clear any remaining dust or chips.
Spread adhesive over the back of the new tile, then press it firmly into the recess, wiping away any excess adhesive that splurges out. After it’s set, you can then apply fresh grout.
If the tiled area is in a shower, leave the grout to set for about a week before using the shower again, otherwise it won’t harden properly.