What Goes Under a Crushed Limestone Tile Floor?

General Information

• Crushed limestone in tile form is a composite material with a fortification of polymeric resin. It often looks like ceramic tile, but is much more durable and won't chip like ceramic tile. A variety of subfloors can be used in conjunction with crushed limestone. It also requires a special adhesive to get it to stick to the subfloor.

Concrete

• Concrete can be used as a subfloor, assuming it meets the criteria, including a clean surface devoid of any sealants, adhesive residue and paint. The floor should also be cleaned before installation. Any gaps larger than one-eighth inch should be filled before installing crushed limestone tiles.

Wood

• Wood floors can provide a subflooring below crushed limestone tiles. Leave 18 inches of air space below the wood subfloors. The wood must be in good condition and solid. The subfloor should be at least 1 inch thick. An underlayment can be added to the wood floors to provide for the necessary thickness. Any gaps greater than 1/32 of an inch should be filled with a patching compound.

Cement Backer Board

• Cement backer board can be used to provide a subflooring for crushed limestone tiles if you have an existing tile or vinyl flooring. Use 3/4-inch thick cement backer board. Apply thin-set mortar to the existing flooring and spread it around with a trowel. Cover an area large enough for one sheet of backer board. Drill screws every 8 to 10 inches into the backer board until they are below the surface of the backer board.

Underlayment System

• An underlayment system can be used to create a floating installation. This material can be used if you have an inadequate flooring, such as a wood floor that has rough patches or a concrete floor with paint or residue. Roll out the sheet of underlayment and leave 1/4-inch around the room's perimeter. Tape multiple sheets together at the seams.

Adhesive

• Purchase adhesive from the manufacturer where you bought the crushed limestone tiles. Spread the adhesive with a trowel onto the subfloor. It will change color to a clear color as it becomes tacky. This will indicate it is time to install the tile.

Grout

• You can install the tile with or without grout lines. Without the grout lines, install one tile at a time with each tile being flush against the previous tile. If you choose to add grout lines to replicate a traditional tile installation, add spacers between each tile. After all of the tiles are laid, rub grout over the entire flooring. Do not use mortar under the tiles.