Yeah...what that other guy said! You wrote that it's "clear glass tile with a white backing". Is the white backing an epoxy coating? Or is the white backing a mesh that the tiles are glued to? One thing to be careful of with glass is the thinset. If you leave ridges in the thinset, you might get uneven bedding of the tile and you;ll see the thinset ridges through the clear glass tile. I'll apply the thinset (white thinset, not gray) to the walls using the notched edge of the trowel, that will get you a measured amount of thinset on the walls. Then I use the flat side of the trowel to knock the ridges down so the thinset is smooth. Then set your tile in that. You want 100% coverage on the backs of the clear glass tiles. Regarding white versus gray thinset, gray can muddy the color of the clear glass tile. A slight tangent, but a lot of times with clear glass tile I've colored the white thinset with pigments for added effect. Mongo

This is what I did in my kitchen and it came out perfectly (the tile guys had better close their eyes now). I went to the craft store and bought some 1/8" thick balsa wood strips and I drew lines on my wall where I wanted the glass tile stripe to be. I then tacked up the balsa wood to mask the stripe. I used drywall compound to build up the 1/8" thick stripe because it was my backsplash and wasn't going to get wet but if I were doing this in a bathroom I'd use thinset. Basically I used a flat putty knife to fill the space between the two pieces of balsa and when I was done and it was dry I had the perfect "platform" to lay the glass tile on. I did it this way because I knew I did not have the practice, skill, or the "touch" to build up thinset on the fly under the glass tile. I do have pictures of my method somewhere if you need them, I'd have to dig them up but I can do that. I was REALLY pleased with how it came out - the thinner glass tile when set is perfectly flush with the thicker field tile.

Soonermagic, Kerdi is the perfect choice for a steam shower. No if's and's or but's. Here's the deal as best as I can describe on the forum...what follows is not a perfect description, but generalities: Unmodified thinset cures via a chemical reaction. Essentially, it does not need air to cure and harden. The chemical reaction consumes water in the cure. Put a dollop of unmodifed thinset in a zip lock bag and it will still cure and harden. Add a latex modifier to the thinset for lightly modified thinset? You still have the "no air required" chemical cure for the thinset, but the latex modifier needs exposure to free air to dry. No air, it'll remain slightly soft. Highly modified thinsets need even more exposure to free air so the additional latex modified portion of the thinset can fully dry. Put a dollop of highly modified in a ziplock bag and it may not fully harden, even after several days. What is Kerdi? A polyethylene sheet membrane. Air can't pass through it. Air can't pass through glass tile either. So a modified thinset will take longer to cure and harden when sammiched between Kerdi and glass than would an unmodified thinset. Small glass mosaic tiles like yours have a lot of grout joints, the modified thinset can "air dry" through those joints. It may take longer than glass over cement board (air can pass through cement board), but will usually eventually dry. This is why Kerdi recommends using non-modified thinset in a lot of their installation documents. It depends on what you're tiling, the size of the tile, etc, but in general Kerdi recommends non-modified, or "dry set" thinset. Glass tile, being smooth, needs something that will grab and hold it. That's why most glass manufacturer's will recommend a modified thinset to adhere glass, as the modified has better bonding properties and has a bit more flex to it, meaning it's bond is not as brittle as a dry set bond. Therein lays the conflict. I've installed a lot of glass over Kerdi. You just need to know what you're doing before you attempt it. It takes a bit of reconciliation between the tile installation instructions and the Kerdi instructions, with a bit of common sense thrown in. Tilers need to better educate themselves before attacking installations like yours. Tile products have evolved over the years, and continuing education is the difference between a true professional and someone who just shows up to work with his lunch pail. I'm not necessarily knocking your installer, but your GC and tiler should have been on top of this long before the first batch of thinset was mixed. Best, Mongo

Here is a link to google, how that backsplash should have been installed. There are some u tube videos too. I watched one video, where they used grout, between the countertop and the backsplash, and grout should not be used there. Caulking shud be done between backsplash and countertop. My backsplash is also caulked in all the corners, rather than grouted. Once you watch these videos and read these articles, you will see that your thinset was put on improperly, and thats why your tiles are falling off. Please read carefully. https://www.google.com/search?source=hp&ei=uI4VW7HdLszKjwTtrqSoAw&q=how+to+install+glass+subway+tile+backsplash&oq=How+to+install+glass+subway+tile+&gs_l=psy-ab.1.0.0l3j0i22i30k1l3.3755.12143.0.14244.41.29.3.9.9.0.173.3348.9j20.29.0....0...1c.1.64.psy-ab..0.41.3556...0i131k1j33i22i29i30k1.0.70wb9L5GlO8