b'ASK THE EXPERTShow well it will serve as a substrateintoconsiderationsuchfactors for your new tile installation. asthetypeandconditionofthe You(orastructuralengineerexisting waterproofing membrane, orsimilar)mustensurethatthewhether 95% mortar coverage was structurewillbeabletosupportachievedintheoriginalinstalla-theaddedweightofthenewtiletion,etc. Youwilllikelyneedto andbondcoatovertheexistingapplyanewmembranebefore installation. Deflection, live loads,installing your tile. Doing this will deadloads,etc.,arepartoftheencapsulatetheexistingtileand consideration.TCNAHandbook bondcoatbetweentwolayers methods for floor installations listofmembrane.Itisimportantto the Service Rating for the method.determine whether adequate bond Also refer to the Performance Levelcoat existed in the first installation Requirement Guide and Selectionto ensure no pockets of water or Table in the 2019 TCNA Handbookother materials are being trapped (page 43) for more information onbetween the membrane layers.Service Ratings. As with tiling over any substrate, If the tile over tile is to be doneitisnecessarytoensurethesub-inawetarea,youmusttakestratemeetstheflatnessrequire-mentforthesizeof tileyouareinstalling. Iftheexistinginstalla-tiondoesnotmeetthe flatness criteria, it must beflattenedwiththe appropriatematerials Established 1990 first. Yoursettingmate-Jenn rialmanufacturercan Web Development Team Mike J. assist you with the cor-Marketing Teamrectmaterials(possibly includingprimers)and Milton Web DevelopmentCorporate Video Productiontechniquestocorrect Greg Graphic Designer Client Support Telephone On-Hold MessagesPrinted Promotional Gear unflat substrates.Insummary,every-Review Management Search Optimization Paid Search Management thing about the existing Anthony substrateandsubstruc-Corain Audio Team CALL US TODAY!Web Development Team ture must be considered beforetilingoveran BryanSales Team Manager existing tile installation.Mark Heinlein, NTCA Training Director30TileLetter | September 2019'