Because of its transparency, hardness, and slick surfaces, glass tile demands different materials, tools, and techniques from ordinary ceramic. Here's what you need to know, from tiling contractor Joe Ferrante, a veteran of many TOH projects.
Tools: For clean, straight cuts, use a diamond wet-saw blade. Nippers with carbide jaws can nibble curves in tile edges. When working with glass, always wear safety goggles.
Materials: The best thinset adhesives for glass tile have two parts: a white powder and a latex liquid additive, such as Laticrete's 317 thinset and 333 additive. Mixed together without water, these two components bond tightly to the glass and provide a uniform substrate. For grout, use an unsanded product fortified with polymers.
Technique: The day before tiling, prep the wall with the thinset mix applied with a straight-edged trowel. This layer hides the cement backer board underneath and ensures a good bond. The next day, trowel on a fresh, smooth layer of thinset about 1/8 inch thick. Then, before setting each tile, "back butter" it with a smooth layer of thinset about the same thickness. "Back buttering is king," says Ferrante. "It makes a superior bond and eliminates bubbles between the tile and the thinset."As you stick the tile to the wall, twist it slightly so any trapped air can escape. Wait four or five days for the thinset to cure before applying grout. Then, after grouting, wait another 36 hours before applying a sealer—only to the grout lines—with a pinstriping brush. "You don't need sealer on glass," Ferrante says.
TIP: To drill a hole through glass tile, use a diamond-tip tile bit. Before starting, press the chucked bit against the mark and twist by hand until you hear its tip scrape against the glass. That will keep it from wandering when you start the drill.
