Installing marble tile is similar to installing other types of tile, such as ceramic or porcelain tile. In fact, the steps are pretty straight-forward. After preparing the subfloor, glue down the tiles, grout, then seal. Plus, if you have previously installed tile, then chances are you already own most of the tools needed to install marble tile.
What You’ll Need
Equipment / Tools
1/4-inch notched trowel
Drill/driver
6-inch drywall knife
Tape measure
Chalk line
Pencil
T-square
Tile spacers
Rubber mallet
Wet saw, if not using custom-cut tile pieces
Diamond-tipped holes saws (if needed)
Utility knife,
Foam brush,
Work gloves,
Grout float,
Grout sponge
Materials
Marble tile
Thinset mortar (tile adhesive)
Cement board sheets
1 1/4-inch cement board screws
Cement board joint tape
Straight 2 x 4 board
Marble tile-and-grout sealer
Grout
Instructions
Prepare the Subfloor
Marble floor tile (like all floor tile) requires a smooth, flat, water-resistant base for installation. In most cases, this will require removing the existing floor covering down to the subfloor layer, which is usually plywood or MDF.
Once you have exposed the wood subfloor, cover it with a layer of cement board to add both stiffness and moisture-resistance to the floor. Cement board doesn’t stop moisture from passing through it—it’s not a vapor or moisture barrier—but it won’t be damaged by moisture as wood is. Cement board also is engineered to bond very well with thin-set mortar adhesive, which you will use to install your marble tile.
To install cement board, spread thin-set adhesive over the wood subfloor, using a 1/4-inch notched trowel. Lay the cement board sheets into the thin-set and fasten them to the subflooring with 1 1/4-inch cement board screws. Leave about 1/8 inch of space at all seams and where the cement board meets the walls.
Apply cement board joint tape (a special alkali-resistant mesh tape) over the seams between the cement board panels, then cover the tape with a thin layer of thin-set, using a 6-inch drywall knife. Make sure the seams are smooth and flat and flush with the panel faces.
Marble tiles are thick, so laying the tiles over the top of the existing floor is rarely practical. Installing marble tile usually requires demolition and removal of the existing floor covering.
Because marble is heavy, your subfloor should be extremely sturdy. This may require some structural work to reinforce the joists supporting the subfloor before installing tiles.
Create Reference Lines
Your installation will look best if the tiles radiate outward from the center of the room, rather than starting abruptly from one of the walls. In order to achieve this symmetrical effect, you need to create reference lines on the surface of the cement board underlayment.
Find the center of two opposing walls and use a chalk line to mark a path between them, dividing the room in half.
Then, measure to the center of that line, and use a T-square to draw a perpendicular line at the mark, using a pencil. Snap a chalk line across the floor using the pencil line as a guide, dividing the floor into four equal quadrants.
Check your layout by test-fitting full tiles along both reference lines from wall to wall. If the last row of tiles against any of the walls is less than a few inches wide, adjust your chalk line grid as needed so that the tiles along the walls are an acceptable width, based on your preference. This usually means that a tile, rather than a grout line, will be at the very center of the floor, but there’s really no drawback to this.
