An symbol of luxury for thousands of years, marble floors are about as classic as it gets. Patterned, colored, polished and rough cut styles are all popular in up-market homes today—no more difficult to install or maintain than other natural stones and tiles.
Step 1 - Inspect the Floor
The surface needs to be even and free of debris or dust. If the floor has any uneven sections, you'll need to put in a plywood layer for the tiles to rest on. If the subfloor is made from concrete, any damage thereto should be patched up first. If the subfloor is made from a softer material, it's a good idea to install some appropriate backerboard before continuing.
Step 2 - Plan Your Design
When the surface is prepared, lay out your tiles to plot the pattern you'll be installing. Ideally, you should start with the first tile exactly in the center of the wall opposite the entrance door. This will make the ultimate feel of the room more peaceful and balanced.
Step 3 - Cut the Marble
The layout will help you figure out how many tiles you'll need to cut to fit the space, and in what shape you need to cut them. Tiles must be cut using a wet saw with a diamond blade. This process is a little delicate, so take your time to avoid causing cracks.
Some people coat the area they're cutting with masking tape to reduce the chances of crumbling. If you have to go all the way through a tile, it’s best to cut it 3/4 of the length and then go to the other side to cut the remaining section.
Safety Note: Stone dust can be dangerous. It’s best to wear heavy gloves, a face mask, and safety glasses during this process.
Step 4 - Put Down the Mortar and Lay Tiles
Use a trowel to apply a 1/4 inch layer of mortar to the first area of installation. It will dry fast, so only spread as much as you need to lay about four tiles. Apply another, thinner layer of mortar to the back of each tile before you place it, and twist the stone slightly as you press it down to set it firmly in place. Try to avoid getting any adhesive on the face of the tiles, it can be a bear to remove.
You may want to use tile spacers to keep the joints between the tiles as even as possible. 1/16 to 1/8 inch gaps will give you some wiggle room in case things get tight. Once all of the tiles have been laid, leave the floor overnight to dry.
Step 6 – Grout and Seal
Once the tiles have set, paint on a thin layer of impregnating sealer.
Mix the grout as directed by the label once the sealer has dried, then gently moisten the space between tiles with a damp sponge, and pack the grout tightly, removing any excess as you go. A grout float can help you pack the substance neatly into the joints. Clean up any extra grout or glue, then leave the grout overnight to completely dry.
If you'd like, you can add one more coat of sealant at this point, just make sure to to let it dry completely before opening the area to foot traffic. When it's ready, give your new floor a gentle wash with some water and you're good to go!