b'? By William A. White, CTI #878TECH TALK To waterproof or not to waterproof, that is the questionNTCA State AmbassadorOR, WA, ID, MT AKARDEX Engineered CementsTile&Stone Team LeaderItalktomanypeoplewhoare notclearonwhenandwhere tousewaterproofi ngundertile installations.Themostsurpris-ingthingIcomeacrossisthose who think that tile, grout, mortar and backer board are waterproof. Unfortunately,therearemany failed installations due to the lack ofwaterproofi ngandimproper waterproofi ng,soletslookat whentoconsiderusingwater-proofi ng under tile.A good place to start is the Tile Council of North America (TCNA) Handbook,whichaddresses waterproofi nginseveralplaces. There are specifi c sections such as the Membrane Selection Guide andtheWetAreaGuidelines thatdiscussmembraneusage. TheMembraneSelectionGuide outlines several different types of The TCNA Handbook for Ceramic, Glass, waterproofi ng, from non-metallic,and Stone Tile Installation highlights the building designers responsibility to know lead, copper, CPE and PVC. Therehow each tile installation will be used and are also the ANSI A118.10 trowel- maintained, to avoid under-designing an applied sheet or liquid waterproofarea for the amount of water it will be exposed to. Courtesy of the Tile Council of membranes commonly familiar toNorth America, Inc. (TCNA).74 TileLetter | December 2019'