ASK THE EXPERTS QUESTION I am a homeowner having a glass tile install performed. The tile is a 3” x 12” glass subway tile with a color backing. It is being installed as the backsplash around the stove/oven. My tile contractor said to butt the glass tiles up to each other with no spacing in between – and to butt them up to the quartz countertop – but I was told by the tile store to use a 1/8” spacing. All I am looking for is your technical opinion on the proper way to install the tiles regarding the spacing to give some instruc- tion to my contractor for the install. The tile edges/corners are flat with no bumpers that would cause a spacing when they are butted up to each other. ANSWER We always encourage our members to follow the guidelines set forth in the TCNA Handbook. On page 37 of the Handbook it states “that in no circumstances shall the grout joint be less than a 1/16 of an inch.” One of the reasons listed for a minimum requirement for grout joint size on all tile installations is “thermal expansion.” Glass tile is highly expan- sive. It also explains that the grout joint should be no smaller than three times the variation of the tiles t h e m s e l ve s . That means if a particular group of tiles vary in size 1/16”, the smallest grout joint recommend- ed for that particular group of tiles is 3/16” of an inch. Most glass tile manufacturers have directions for the use of their products. I would encourage you to contact the manufacturer of the glass to get their recom- mended grout joint size. And make sure there is the appropri- ate sealant joint where ever the tile meets differing materials like a countertop or cabinet. I hope this helps. – Robb Roderick, NTCA Technical Trainer QUESTION I plan to have a small bathroom Sponsored by 18 TileLetter | March 2018