Installing Stone Tile

Intro

Stone tile requires the same firm and level setting bed as ceramic tile -- only more so. Because stone is brittle and the minerals that make up its pattern are not perfectly "cemented" to each other, it is subject to fracture along the grain lines.

Stone also suffers from the normal physical inconsistencies found in any natural material. Some pieces might not be exactly as wide or thick as the others. Adjust length and width by cutting the tile with a wet saw and accommodate differences in thickness by adjusting the amount of mortar you spread.

When set, the top edges of all tiles should be flush. Back-butter each tile before you set it in the mortar bed and test it to make sure its edges are flush with its neighbors.

Most stone tile comes from the factory with beveled edges, so cutting a tile will leave it with an unbeveled edge. Hone the edge of the cut tile with a rubbing stone or with sandpaper wrapped around a block of wood. To polish a tile to a high sheen, use progressively finer grits of carbide sandpaper (from 120 to 600).

Checklist

Time
About 10 hours for an 8x10-foot room. Allow 3 to 4 hours for grouting and cleanup on the next day.

Tools
Chalk line, tape measure, carpenter's pencil, power drill with mixing paddle, notched trowel, beater block, rubber mallet, grout float, 4-foot metal straightedge, wet saw, dry-cutting saw

Skills
Marking, setting, and cutting tile

Prep
Remove existing flooring, repair or replace underlayment

Materials
Thinset mortar, stone tile

Previous | Next

Cut with dry-cutting saw, Knock out with tile nippers

What If... You Have to Cut a Hole in the Stone?

Cutting holes for obstacles such as electrical outlets becomes a relatively easy task with a dry-cutting saw equipped with a diamond blade. The saw allows you to get almost all the way into the corners to make a clean cut. Mark the outline with a china marker (not a felt-tip, which may bleed). While a helper steadies the tile, lower the saw into the middle of the line. Work the saw forward to one end of the line, then back to the other corner. Knock out the cut piece with tile nippers and trim the corners square. Don't worry if the cut line is slightly off; it will be hidden under the wall plate.

Step 1

Stone tile often has a dusty residue on its back that weakens the adhesive bond. Wipe your finger across the back of the tile and if it comes up dusty, clean the backs of the tiles with a sponge and water. Let the tiles dry before bedding them.

Previous | Next

What If... Edge Tiles Are Not Available?

Some manufacturers produce stone bullnose, but if your choice doesn't offer them, you can make your own by rounding the edges with a rubbing stone. As an alternative, start with coarse carbide sandpaper wrapped around a wood block and polish with finer grades.

Step 2

Lay out a dry run so the edge tiles are the same size. Then snap lines as guides. Using white thinset mortar for light-color tiles, trowel thinset on the subfloor and back-butter the tile. Set and level the tiles, adding mortar to the back as needed. Line up the tiles with a straightedge.

Previous | Next

Use Adhesive Alternatives for Stone

Granite tiles make an attractive substitute for a granite slab on a countertop. If your tiles are cut to a consistent thickness, you can use silicone adhesive instead of thinset. Lay the tiles in a dry run. Then lift one at a time, apply silicone to the substrate, and press the tiles in place. Line up the tiles with a straightedge.

For some stone tiles, expensive epoxy mortar is the preferred adhesive, but you might be able to get around the cost by sealing the back of the tile with a nonporous epoxy sealer. Once the coating has cured, you can set the tiles in regular thinset mortar.

Step 3

When the mortar for the field tiles has set sufficiently (usually overnight), cut the edge tiles with a wet saw and lay them in a mortar bed, back-buttering each tile as you go.

Previous | Next

Step 4

Let the mortar for the edge tiles cure for 24 hours. Then mix a batch of unsanded grout, just enough to cover a small section. To keep the stone tiles from absorbing too much water from the grout, wet them with a spray bottle. Apply the grout with a float. Remove excess grout from the surface of the stone. When the grout has set for about 15 minutes, wipe the haze with a damp sponge. Finish grouting the entire installation, working in sections so you can clean the excess before it hardens. When the grout has completely cured, seal the tiles as necessary.

Previous | Next

Comments