How to Build a Limestone Surround for a Wood Stove

Mark the dimensions for the surround on the floor and the walls with a pencil. Most localities regulate the size of wood stove surrounds per building code so check the minimum dimensions when purchasing your permit. Having a fire-protected hearth floor is essential, whereas the stone on the walls behind the stove is optional in most areas.

Lay out the limestone tiles on the substrate in the desired pattern. When possible, create a design that will require as few cuts as possible. Use spacers between the tiles to allow for the grout lines. Measure the sides and top of the wood stove and lay out tiles for these areas on the floor as well. Generally, the tiling will start from the front and largest wall, with any cuts kept to the back wall.

Prepare the substrate. The subfloor should be solid wood, with the floor joists spaced 16 to 24 inches on center. If the floor has any flex, cover the substrate with a piece of sturdy plywood nailed to the substrate every 12 inches or add blocking between the joists. Blocking consists of pieces of 2-by-4-inch or larger boards cut to fit between the joists. Blocking is sometimes accessible from the underside of the floor. The prepared surface should be level and smooth with no flex. If the floor has flex, it will break the tiles and grout.

Cut sheets of polyethylene membrane for the area to be tiled with a utility knife. Apply thin set mortar to the floor with a v-notched trowel; maintain a 1/4-inch gap between any wall or wood trim. Place the membrane waffle side up over the moist thin set. Use a grout float to press the membrane solidly into the mortar. Add additional sheets until the entire area is covered. This membrane absorbs the movement of the wood subfloor and prevents this movement from cracking the limestone.

Measure the width and length of the installation area and snap a chalk line across the center of each measurement. These lines will help guide the straightness of your tile installation. Unlike other installations which tile from the center out, your primary edge is the tiling that faces the room. Snap a second chalk line along your primary edge. You will want any cut tiles to fall behind the stove.

Tile the floor and surrounding walls based on your earlier layout and plan. Apply thin set to the top of the membrane and to the underside surface of each tile. Line the tile up with your starting point and keep it straight along the edge that faces into the room. Press the tile into the thin set and wiggle to seat it firmly in place. Some tiles will need to be cut. Use a wet saw to cut the tile before installing it. Always cut the tiles as you go, rather than before you start your floor, since the spacing of your tile will vary during installation.

Set a spacer next to the first tile, apply thin set to the back of the next tile then press it in place. Check the straightness of the tiles with a level. Wipe the grout lines to remove mortar at least half the thickness of the tile with a damp sponge. This is the mortar that oozes out around the sides of the tiles during installation. No mortar should be left on the face or grout lines overnight. Tile the entire surround area. Allow the mortar to dry for 24 to 48 hours before proceeding.

Seal the tile if it is porous. Limestone may have bubbles or holes in the face of the tile. If this is the case, seal the limestone before grouting it so that grout will not adhere inside these porous areas. Use a limestone sealer applied with a foam brush. Allow the sealer to dry completely before grouting.

Remove the spacers between the tiles. Mix grout in a bucket then pour it into a grout bag. Squeeze the bag to disperse the grout from the applicator tip into the areas between the tiles. Spread the grout evenly with your finger. Clean off any residual grout, as you work, with a damp sponge.