ASK THE EXPERTS QUESTION I’m having issue with glass tile for one our customers. We’re try- ing to determine what’s causing the cracking. I believe it might be due to the thinset shrinking. Is it pos- sible that it may be the tile? ANSWER Yes, it is possible that the glass cracking could be due to thinset shrinkage as it cures, especially if the maximum bond coat thickness of the thinset was exceeded. But looking at the two photos you sent, here are my guesses. In the first photo that includes the glass door and hinge, it appears that the glass may potentially have cracked from: • over-tightening of the screw through the hinge • a minor misalignment of the hole drilled in the glass to accept the screw • weight of the door on the fas- tener at the pressure point if all components of the door installa- tion were not properly aligned or balanced. In the second photo showing the closeup of the grout joint, it is dif- ficult to know what caused these small fractures. The photo is taken too close to see a context of the location in the shower. It appears that the photo was taken very close to the glass and the fractures are fairly small. My guess is the frac- tures may have been in the tile at the time it was installed and they weren’t noticed by the installer. If you need a solid determina- tion of these fractures, a third party consultant that can make an onsite evaluation may be needed. I hope this helps. – Mark Heinlein - CTI #1112, NTCA Training Director, Technical Trainer / Presenter QUESTION We are members of NTCA and would love some technical advice Sponsored by 30 TileLetter | January 2018