How to Install Slate Mosaic Tile Around a Fireplace

Measure the fireplace surround in three sections, using a measuring tape. Measure the top of the area above the firebox, extending out to each side and above, and each of the two legs on either side of the firebox to the top of the box. Create an area of equal size and shape nearby on the floor.

Lay out the sheets of slate mosaic on the floor where you marked off the size and shape of the surround. Note if any sheets are particularly thinner than any other. Cut the mesh holding the mosaics together to fit the sheets to the edges of the installation where needed. Cut any individual tiles with stone tile nippers.

Spread a thin layer of white latex thinset onto the fireplace surround with a trowel, beginning in the center of the area directly above the fire box. Spread a second thin layer of white latex thinset directly onto the backs of each sheet of slate mosaics as you install them.

Press the bottom of each sheet onto the surround and smooth the slate mosaics upward with the heel of your hand. Place a flat board over the mosaics and beat it with a mallet to embed the slate in the mortar and even out the depth. Let the thinset dry overnight.

Seal the slate mosaics with stone sealer. Use a sponge to apply the sealer to the entire fireplace surround, taking care to seal any grooves, crevices or tiny holes in the slate to help release the grout. Wait 10 minutes and buff away any excess sealer from the mosaics with a soft cloth.

Grout the slate mosaics with a rubber grout float, spreading grout over the entire surround at once to pack the grout between the tiles. Clean the grout off the face of the slate mosaics with a damp sponge after 10 minutes. The grout will continue to dry over the next three weeks.