• To secure good contact between tiles and ribs of latex-Portland cement mortar, tiles must be pushed and slid into the mortar using NTCA recommendations for bedding tiles. Backbuttering tiles with a thin, flat coat of latex-Portland cement mor- tar helps develop a better bond to the tile. • On large format tile, a box screed has proven to be an excellent means of controlling the amount of mortar applied to the back side of large tiles. Latex-Portland cement mortar applied to the substrate should be troweled out evenly in one direc- tion – not swirled – with notched trowels. Ribbed mortar on only one surface helps reduce voids and air pockets. This method also produces a smoother, more even surface than conventional backbuttering, which often leaves tiles with excessive lippage. • Successful installations of large porcelain and glass-bodied tiles require the use of a manufac- turer’s recommended latex-Port- land cement mortar that meets or exceeds ANSI specifications. Use latex-Portland cement mortars that are more flexible, in addition to having superior bonding capabil- ity. Latex-Portland cement mortars bond large porcelain tiles and tiles containing glass in the body, bet- ter than more conventional mor- tars. Mortar flexibility helps bridge stresses created between substrates and large, unforgiving tiles, reduc- ing possibility of tiles shearing off. Check with manufacturer for exact products recommended. • Press or slide tiles into position using NTCA recommendations for bedding tiles. Check to see that uni- form contact is being achieved at corners, edges, and the back of the tiles by pulling tile up for examina- tion. Beating-in only of larger tiles generally is not effective. Average contact area shall not be less than 80% except on exterior or wet area installations (see TCNA Handbook for wet area definition) where con- tact area shall be 95% when not LARGE FORMAT TILE ––––––––––––––––––––––––––––––––––––––––––––––––– Fiandre recently introduced the U.S.- made West Loop, named for the emerging Chicago neighborhood and resembling textured industrial concrete. It features high color variance including 35 shading patterns, with metal undertones. In four colors in 24” x 48”, 24” x 24”, 12” x 24”, 8” x 48”, 12” x 12” mosaic and 4” x 12” diamond. www.granitifiandre.com 84 TileLetter | May 2017