How to Properly Install Slate Tiles

Grind off any ridges or bumps in the concrete subfloor with a concrete grinder, and fill cracks or pits with a concrete leveling compound. Use a carpenter's level to check that the surface is even.

Hose off debris from the surface, scrubbing it with a scrub brush and concrete stain remover if it is stained. Rinse off cleaning solutions thoroughly.

Locate the midpoint of one side of the porch and snap a chalk line straight across. Snap another chalk line from the opposite sides. The spot where the lines intersect indicate the center of the porch or patio. Plan to lay the tiles from the center and work your way out in straight rows.

Dry-lay the tiles over the surface to create the pattern you want. Number the back of the tiles so you can install them in the same order and remove them from the surface.

Lay a coat of bonding adhesive over the surface with a small sponge roller to help the mortar stick to the concrete.

Mix thinset mortar with water, following the instructions on the package. If the surface is large, mix small, manageable batches at a time or it can harden before you use it. Blend until the consistency resembles hot cake batter.

Apply a ½-inch layer of mortar over the center point of the surface with a notched trowel. Spread only enough to lay about six tiles at a time.

Press the tiles into the mortar from the center. Work across in rows and place rubber spacers between each so the grout lines are even and about ½ inch apart. Continue to set the tiles in rows until the surface is complete. Give the mortar two days to dry.

Coat the slate surface with grout release agent with a sponge to prevent the stones from absorbing any grout spatter stains.

Mix sand grout with a small dose of water to make a stiff mixture that can hold the shape of a ball. Pack the grout between each tile with a trowel and wipe off excess. Clean grout from the surface with a moist sponge. Allow the grout to set for one day before using the surface.