It might be hard to tell from pic, but between the first and second rows, the tile have begun to lift as if there is an air pocket under it. It sounds hollow under that area versus the rest of the shower area. Also in this area, the grout is wearing and could potentially allow water intrusion.
I called this out as an area of concern. The owner is telling the buyer that its nothing. Is my reasoning sound for it being a potential issue underneath the tile?? Is there any other testing that I could have done beside visual and the hollow sound of the tile itself?
You made your report sounds hollow , Hope you recommended repair .
No longer your concern ,move on say nothing do not get into an argument or discussion.
Worst that can happen is a few tiles pop off…easily fixed. No issue with water intrusion. The water goes right thru that grout and into the pan liner for drainage.
Once a piece of tile gets a little loose it will start to build calcium beneath it and cause it to lift further. The standard test for a shower pan is to elevate the water level to approximately 1 inch and let it stand I then use a moisture meter and IR to detect leaks
I have a large amount of homes in my area built in the 70"s all with tile shower stalls. I have a set routine for checking pans for leaks. I take digital’s of all sides of the stall that are exposed along with IR images of the same walls and they all go into my reports even the ones that don’t leaks. If there are no leaks my images are CYA for future reference.
BTW the average cost of shower pan replacement in my area is $1500.00 to $2000.00 and I have never had to pay for a leaking shower pan. :D:D