Gather Your Materials
Although real slate tile is a durable flooring material, it is possible for individual tiles to become chipped, cracked, or otherwise damaged beyond repair. And as strong and impervious to wear and water a tile floor is, it's also one of the easiest types of flooring to repair. To replace a damaged tile, you simply scrape out the grout around the tile, break up and chip out the tile, then scrape off the old adhesive (which most likely is thinset, a grout-like mortar adhesive) so you can start over with a clean subfloor surface.
- Safety goggles
- Carbide-tipped grout saw
- Nail set
- Cold chisel
- Putty knife
- Thinset mortar
- 1/4-inch notched trowel
- Rubber mallet
- 2x4 board
- Small screwdriver
- Tile spacers (optional)
- Needlenose pliers (optional)
- Replacement tile
- Tile sealer
Remove the Old Grout
Scrape out the old grout around the broken tile, using a carbide-tipped grout saw. Be careful not to chip or scratch the surrounding tiles as you work. Use a gentle but firm motion to remove all of the grout until the side of the tile is completely exposed.
Break Up the Tile
Use a hammer to drive a nailset into the surface of the tile to puncture it in one or two places. This breaks the slate up so that you can remove it. Be sure to wear safety goggles to protect your eyes from sharp flying chips of stone.
Remove the Tile Shards
Place the point of a cold chisel into one of the cracks and lightly tap the chisel with a hammer to loosen and pry up the pieces of the tile. Chisel very carefully near the edges of the tile to prevent damage to adjacent tiles. Break up just the tile and old mortar layers, being careful not to damage the subflooring or tile backer material below.
Remove the Old Adhesive
Scrape away the old adhesive with a putty knife or cold chisel. Remove as much of the adhesive as possible, then use coarse sandpaper to remove residual adhesive and to smooth the area. Remove all grit and dust from the floor with a shop vacuum.
Place the New Tile
Mix a small batch of thinset mortar as directed by the manufacturer. Apply mortar directly to the back of the tile, using a 1/4-inch notched trowel. Drag the notched edge of the trowel through the mortar to make even ridges. Make sure that the entire bottom surface of the tile is covered.
Set the tile in place on the floor and press it down until its surface is level with the surrounding pieces. You can twist it slightly back and forth to get it to sit down into the mortar. If desired, place a tile spacer at each of the four corners to ensure that your grout lines will be straight. Otherwise, simply align the tile by eye so the grout line is all the same width.
Tap Down the Tile
Lay a straight piece of a 2x4 board across the newly placed piece so that the board touches at least two adjacent tiles. Tap the board lightly with a hammer or mallet to press the new tile down so that it rests even with its neighbors. You can also use a level to ensure that you have the tile flush.
In the case of cleft slate, the surface of the tile may be irregular, making it impossible to get it perfectly even with the rest of the floor. Focus on getting the edges of tiles such as these even with adjacent pieces along the grout line.
Clean the Installation
Use a small screwdriver to remove excess adhesive from the grout lines. Wipe any smeared mortar from the tile surfaces with a damp cloth. Use a pair of needlenose pliers to carefully remove the spacers at the corners. Let the tile to set for at least 24 hours.
Grout the Tile
Mix a small batch of grout as directed by the manufacturer. Apply the grout to the grout lines around the tile, using a putty knife. You can also use your fingers to force the grout down into the gaps. Wipe off any excess that gets on the surface of the tiles with a cloth.
When the grout does not yield to light finger pressure, carefully wipe over the grout lines with a wet sponge to smooth the grout and clean the tile surface. Rinse the sponge frequently in a bucket of clean water. It's ok if the grout leaves a haze on the tile surface. Let the grout dry overnight.
Clean and Seal the Floor
Clean the entire surface of the floor with warm water, making sure that you remove all dirt and debris. Allow this to dry thoroughly. Apply a commercial-grade below-surface natural stone sealer to the entire floor as directed by the manufacturer. The sealer will soak into the stone, creating an invisible barrier and making the individual tiles shimmer with enhanced color. This will help to blend the new piece into the rest of the installation.