Covering your walls with slate tiles provides that noncombustible surface, along with some rustic style that complements the wood stove's look.
Determine Which Walls to Tile
Not all wood stoves put out the same amount of heat or have the same recommendations for how far from a wall they must be installed. The general rule of thumb, however, is to install your wood stove a minimum of 36 inches away from a combustible surface in all directions, including above, below, behind and to each side. Therefore, if you plan on installing your wood stove within 36 inches of any wall surface, plan on tiling it. Expect to install the tile to a minimum height of the wood stove plus 36 inches as well.
Put up Backerboard
Slate tiles measure approximately 3/8-inch in thickness. So while the slate itself is noncombustible, the tiles are not thick enough to protect your drywall and studs from the heat of the wood stove. To ensure that your walls are noncombustible, remove the drywall from the areas where you plan to install the slate and put up cement backerboard instead. Place noncombustible 1-inch spacers between the backerboard sheets and the studs. Screw the backerboard sheets right to the studs through the spacers, leaving a 1/8-inch gap around the perimeter and between the sheets. The spacers will keep the backerboard from touching the studs; if the backerboard were to super-heat, it would not cause the studs to heat as well. Tape the seams between the sheets with fiberglass tape and skim coat with thinset mortar 24 hours before installing the slate.
Sort and Layout
Made of layers of compacted mud, slate has a naturally cleft and uneven surface texture. Depending on the type of slate, it may also have a wide variety of color variation, as well as thickness variation between the tiles. Take measurements of each wall you plan to install and lay out the slate tiles in an area of equal size and shape. Sort through the slate as you lay them, blending the colors of the pieces for a pleasing look. Arrange the thicker tiles to sit next to one another and the thinner tiles to sit together. Use tiles that are thick on one half and thin on the other as edge or cut tiles, discarding the thinner half.
Install
Plan on transferring the slate tiles directly from your dry layout onto the walls. Apply a layer of thinset mortar directly to the backerboard with a trowel, raking the mortar with the trowel's notches until it is uniform in thickness. Apply additional mortar to the back of each piece of tile. Mound up an approximately tangerine sized amount of mortar onto each of the slates corners, then push the slate onto the wall and beat it into place with a rubber mallet. For thicker pieces of slate, use a little less mortar; thinner pieces require additional mortar to make up the thickness difference. Allow the mortar to cure for 24 hours, then seal and grout the slate.