Limestone flooring is available in various finishes, from smooth to a rough natural stone look. Since limestone is relatively soft, prevent edges from chipping by separating the limestone tiles with a grout line. Prepare concrete sub-floors by removing all debris and paint overspray and then leveling the floor with a self-leveling compound. Install a layer of concrete backer-board over wood sub-floors to prevent sagging and moisture encroachment. Choose tiles sized to fit against the longest wall so that the cut tiles at each end are at least half the width of a finished tile.

Instructions as follows:

Firstly, measure the midpoint of the longest opposite walls with a steel measuring tape. Stretch a chalk line across these points. Lift the string about 1 foot and then let go to snap a chalk line across the center of the floor. Mark the center point on the skirting board with a grease pencil as a guide for your first tile.

Secondly, follow the manufacturer's instructions and mix a small plastic tubful of polymer modified thinsets mortar. Spread a layer of thinset mortar across the floor with a notched trowel. Hold the trowel at a 30 degree angle. Spread the mortar in semicircular arcs while maintaining contact with the surface by scraping the teeth of the trowel against the floor.

Thirdly, place 1/4-inch spacers between the first row of tiles and the wall to maintain an expansion gap.

Fourthly, position the left corner of the first limestone flooring tile against the mark on the center of the wall. Press the tile into the thinset with a slight rocking motion. Tap the tile down with a rubber dead-blow hammer while holding a spirit level on the surface. Adjust until the bubble is centered in both directions across the tile.