Stone Floor Installation
- 1). Prepare the floor for installation by removing the existing floor covering. If the surface is wood, install concrete backer unit (CBU) board on top of the wood before installing the stone. Remove all molding and doors. Sweep and vacuum your floor.
- 2). Start the installation in the center of the room and work out toward the walls. Divide your work area into quadrants by measuring to the center of each wall and snapping a chalk line between the center points of each wall. Lay a row of loose stone and spacers for grout in every direction, beginning at the center-most point of the room. If there are cuts measuring less than 1/2-inch next to the walls, move your center point toward the walls by 1/2 inch and re-snap your chalk lines. Divide each quadrant into smaller, 2-by-3-foot sections with additional chalk lines.
- 3). Mix thin-set mortar according to the directions on the bag. Use a notched trowel to spread a thin layer of the mortar across the surface of one of the quadrants. Do not cover your chalk lines. If you are using stone tiles larger than 16 inches, cover the backs of the tiles with mortar as well.
- 4). Set the stone into the mortar. Add spacers, working quickly to lay the stone down before the mortar develops a skin on the surface. Once all the tiles in a quadrant are laid, tap each stone tile lightly with a rubber mallet. Check that all tiles and spacers are even by laying a level across the surface and adjusting where necessary. Repeat Steps 3 and 4 until the entire floor is covered in stone. Prepare a new batch of mortar in a bucket every 30 minutes throughout the process.
- 5). Allow the mortar to set and cure according to the manufacturer's directions, which will usually be 48 to 72 hours. After the mortar has set completely, grout the joints between the tiles. Remove all spacers across the floor. Sweep or vacuum the floor to remove debris. Sand down any high spots in the mortar between the tiles. Mix the grout according to the manufacturer's instructions, mixing only what you think you can use in 30 minutes. Wear rubber gloves while installing grout.
- 6). Start in one corner of the room and spread grout across the face of the stone. Force the grout into each joint with a squeegee. Scrape away excess grout from the face of the stone. Discard grout when it becomes stiff (usually after 30 minutes). Leave any movement joints un-grouted, as you will need to fill them with caulk later.
- 7). Allow grout to set for 20 minutes. Gently wipe away grout from the face of all stone with a large sponge and bucket of clean, warm water. Replace water as it gets dirty. Let the floor cure for 72 hours, taking care not to walk on it or put any furniture on it during that time. Seal the floor, if desired, particularly if the room is a bathroom or other area that you expect to get wet.
