According to the Tile Council of North America (TCNA), any tile or stone format that is 15 inches or larger on either side or weighs more than 20-30 pounds is considered large format. Large format slabs require specialized tile mortar with polymers and additives that support the weight of the slab, minimizing sag and slump. The use of self-leveling underlayments and leveling systems is highly encouraged to minimize lippage in this critical installation.
