TILES FOR STEPS
Flat piece of natural stone, obtained by machine cutting or natural split, with a nominal thickness exceeding 12 mm, to constitute both the vertical of a step, and the horizontal section whose width exceeds two times its thickness. The units that make up the riser can reach a minimum nominal thickness of 10 mm, if its stability is guaranteed. The dimensions of a tile for stairs are the length, width and thickness. Dimensions should be reported in this established order.