Mix the thinset tile adhesive according to the manufacturer?s instructions. For a large tiling job, use a drill with a paddle bit to mix a large quantity at once.
Installing the slate follows the same procedure as for any other tile: Apply thinset to the wall with a 1/4"x1/4" square-notched trowel (Image 1), place the tile and wiggle it into place for maximum adhesion (Image 2). This design doesn't use any grout; set the tiles flush with each other on the wall.
Note: If taking a break during tiling -- whether for lunch or to cut some custom tile shapes -- make sure to scrape any excess thinset off the walls so it doesn't dry on the wall.
The new bathroom design includes wall-mounted faucets and hardware. To fit the slate around these fixtures, line up the tile over the fixtures and mark the width on the tile. Then, measure the height of the fixtures and mark the height.
Use a wet saw to cut the slate as needed. To make holes for fixtures, first use the saw to cut at each edge of the material to be removed, going up to the height of the fixture. With these cuts done, run the tile through the saw several times to remove material between the edge cuts.
If one of the stacked slate pieces comes away from the tile, butter the piece with thinset and set it in place when mounting the main tile.
For pieces that are cut to go around plumbing fixtures, butter the back of the tile with thinset instead of applying the adhesive to the wall. Place the tile and wiggle it into place to adhere.
Once the tiling is complete, let the adhesive cure according to the manufacturer's instructions.