Repair Slate Tiles
Instructions as follows:Firstly, break away the grout surrounding the broken tile carefully, using a utility knife. Chip and scrape away as much of the grout as you can and try to lift the tile. If the tile won't budge, try breaking the tile into smaller pieces, using a hammer and chisel at the center of the tile. Pound the tile lightly so as not to break any nearby tiles.
Secondly, remove the pieces of broken tile. Scrape away the grout left behind, using the utility knife. Clean the hole with a shop vacuum, and sand it to make it smooth.
Thirdly, place the replacement tile in the hole and check its fit. If it fits flush with the other tiles, spread tile adhesive on the back. Firmly press the tile into place. Cover the tile with masking tape and allow the adhesive to dry overnight.
Fourthly, remove the masking tape and apply pre-mixed grout over the surface of the slate tile. Place the grout on a sponge and cover all of the areas of the tile and the edges of the neighboring tiles.