QUOTE(1tanmee @ Aug 3 2018, 07:27 PM)
Nothing major, I suspect? Placed my hands on the tiles, does not seem to be wet - this should rule out plumbing issues
QUOTE(slimey @ Aug 3 2018, 08:15 PM)
if plumbing issue you will see water coming out of the grout or the other side of the wall have paint peeling or "bubbling" of the paint.
My house came with 5' tiles and I wanted to add 3 more rows above in bathroom. The contractor chipped the wall a bit only and barely called it holes and the chips were quite far apart, even more than a tile size away at random. They did not even bother about the paint. However, now it is already 10 years and the tiles are all still intact.
I guess it is because now the tile are no more attached with cement but special mortar with adhesive. A section of floor tiling was also layered with another tile to create tile high elevation so that the water will not flow to
dry section (name I called). the floor tile was just attached to the top of existing tile and they are still fine after 10 years
So, I guess your contractor was not doing good job or using wrong material or did not know about new material.