Are there minimum sizes of tiles to be used?
Stoneware tiles and hard natural stone slabs, e.g. granite, must be a minimum size of 200/200/10mm; softer natural stones, for example limestones such as travertine and jurassic limestone require thicker material (from 123mm). Only natural stone slabs that are suitable for outdoor areas and are shape-retaining are suitable. Types of stone that tend towards dishing or curving through swelling on contact with water or respectively adhesive mortar (even on one side) are not suitable.
