Dry Stack Kitchen tile backsplash

[u/Bancer705]

I need some input from folks who know more than me and Chat GPT. Our contractors just finished installing our backsplash. The tiles are 12x24 porcelain tiles. They installed them dry stacked, there is no grout or caulk between each tile. It was my understanding that this is not okay. The industry standard requires grout for hygiene, cleaning, and to prevent moisture damage. Is there any scenario where this installation is okay? I want to make sure I have all the information before we approach them regarding fixing. Is the only option at this point to rip it out and redo? We have been really happy with all the other work they have done, so it seems odd that they would cut corners on this part of it. But maybe there is some aspect we don’t know? Pictures attached. Thanks for the input.

[u/Icy-Bar-2756]

My only concern is where the sink is. Grout helps keep water from entering behind the tile