erties such as extended open time, flow to achieve coverage, and curing parameters appropriate to the application – as well as a requirement for suitable mortar identification through consulta- tion with the tile and setting mate- rial manufacturer – are specified in the standard. Trowels: Only Euro-trowel, Flow- Ridge trowel, and Superior notch trowel can facilitate ridge collapse without the need to press and slide the tile. The group agreed to stan- dardize the use of such trowels. Embedding procedures: For floors, physically walking on the surface in the following pattern produces the greatest supporting mortar coverage: 1) walk down the centerline of the tile; 2) take small shuffling steps left and right from center to push air toward the edges. This standardized procedure is listed in ANSI A108.19 for embed- ding tile panels/slabs on floors. For walls, a vibration tool and weight- ed beat-in paddle are specified in order to achieve optimal coverage. For walls and floors, a vibra- tional tool used at the perimeter achieved full coverage on the edge, critical for overall durabil- ity in flooring applications, and also facilitated full encapsula- tion of lippage control systems. For these reasons, edge coverage achieved through vibration is a provision of ANSI A108.19. The standard minimum required cov- erage is 80% for walls and 85% for floors. Additionally, maximum void size was established as 2 square inches (1290 square mm). TECH TALK –––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Increased coverage is shown on the left, achieved with the use of a vibrating sander. Trowels that facilitate ridge collapse with- out the need for pressing and sliding are preferred. 4 64 TileLetter | April 2018