I have no technical know-how whatsoever, but when you pick up this thread yourself you will find other "pebble shower floor" threads on the right. Pick them up and read them -- you may get insight into other people's experiences. I'm so sorry you're having this problem, and I think your friend must feel dreadful, too.

If tiles are falling out right after the job was done then the job wasn't done correctly. The good news is that if they are coming out so easily he should be able to remove them all without damaging the pan. Then the entire job needs to be done over using a better adhesive. I would go to the company to see what they recommend to use for this stone.

Thank you for your responses. I'm going to ask him to take them out and contact the manufacturer.

I should note that these are the super small pebbles not the standard size.

Installer error, not manufacturing error. Sorry to say to your friend.

Yes...this is sad. Hopefully there will not be any issues with the friendship. I'm wondering if your friend was trying to say, without admitting lack of knowledge, that he didn't know how to do this. By him 'not recommending' this type of floor, I wonder if he was trying to say, "I can't do it. You will need a full-paid tile setter for this".

I wish he would have put his foot down and said, "If this is what you want, I will have to bring in someone else. It will cost you much more than you have budgeted." If he had made a statement like that, would you have chosen another shower floor?

I can't help but wonder if the product you chose is the real issue. You said they are very small pebbles which obviously means that there is very little surface area on the bottoms of the pebbles for the thinset adhesive to grab onto. If the pebbles vary in size you may also have some that end up barely even reaching the thinset because the installer would have been forced to use a thinner than normal layer of thinset to avoid too much adhesive squeezing up between the stones. I strongly suspect that it is not an ideal product to use because of the overly small size of the pebbles, and the very real challenges that they would present.

In this scenario and judging from afar, it is far from certain that the installer played a greater role than a poor product choice.

Thank you for all of the responses. We have decided to take the floor out and go with a different shower tile floor. Also, no problems with the friendship. I honestly don't think he knew how to install it either, but he did everything else beautifully and I'm happy.

Most of the information I read said to use sanded grout with the stones and he said he didn't use sanded grout because the spaces between the stones were so tiny that it wouldn't fit between the cracks.

I was second guessing my stone choice anyway because I've read a lot about mold problems with them and I'm allergic to mold.

Sounds like a good plan. Really the grout should not be what one relies on to hold the stones. That is the job of the thinset adhesive that the stones are set into. With pebbles the grout does play a bigger role than normal, but still it's not likely that the type of grout is the source of your failure.

I’m going through a similar issue now and researching such problems. My contractor, also a good friend has determined it is actually an inferior product issue, and another tile store agrees. The type of adhesive that was holding the rocks onto the mesh was absorbing water around the drain where it most pools, allowing for saturation and causing large chunks of grout to pop out. Getting a new floor now. Just bummed that we also chose a river rock stripe around the eyeline of the shower.

@Trohen that does not really sound like a plausible explanation for loose grout. Given the amount of adhesive on typical mesh sheets ( not very much really), and given the fact that when the sheets are installed the whole mesh and lower portions of the stones are embedded into thinset ( not grout). The expanding adhesive theory would mean that it is breaking apart the cured thinset followed by grout. At that point I suspect you would be losing stones also.
More likely problems... some stones were not properly embedded in thinset, and they move even slightly as they are walked on...in turn, the grout will crack and fail. If the base was not properly built...same issue. If grout was too wet...too dry... or worked with for too long or stones were not clean before grouting....
Water should not be pooling anywhere, ever, ... particularly at the drain. How was waterproofing done? If you have a saturated shower base ( very hard to tell by visual inspection) you will probably face issues with mold in the future because the shower base is unable to dry between shower use.

Thanks for your feedback Kivi! Whatever the cause, I’m getting a new shower floor out of it. I’d probably never suggest river rock to other people, and can’t wait to see the new choice finished.

They make a thin set/grout combo material that is fantastic for mosaic tiles, and rock floors, it is thin set and grout all in one, available in colors as well!!!

We have an issue with sliced pebble shower floor. How did you resolve this? Thanks!