That is why you don't let builders install your tile.
I have been in the tile business for over 50 years and have seen some **** jobs done by those who have have uttered the words " I use to do tile". Apparently not good enough to make a living at it!
The home I now live in (W NC USA) was renovated about 6-7 years ago by the previous owners. A quite a lot of work was done to the home, New roof, heat pump,enlarged deck and converted sun room.
New kitchen cabinets backsplash tile (glass) two baths tiled and the entire main floor tiled, no wood anywhere.
I have since ripped out the glass back splash tile, and the Corian counter tops and replaced them with quartz counter tops and a light grey 3"x6" tile.
On to my latest project, about two weeks ago my termite guy came to do the yearly inspection, and when he came up from the crawl space he told me I had a leak from the master bath as there was water in the crawl space.
Over all the job looked good as far as the joints were uniform and grouted properly. My wife was happy at the prospect of new tile as she did not really like what was there.
I started the rip out a few days ago and found the cause of the leak when the builder installed the PVC pan liner when he came to the threshold he just cut it and folded it over the curb. There was no liner going up the walls at each end of the curb!.
He also did not do any water proofing on the bench seat, or the recess, I think he was also trying to conserve on screws as some backer boards only had a screw at each edge (three feet apart) some were 1 1/4" and some were 1 5/8". None of the joints of the backer were taped or filled with thin set. One other thing, he used a 1/8" v notch trowel and most of the tile came off the backer with nothing sticking on them!
I will get some pictures and post them, later on today