when he cleans the grout away on the final washing, make sure no divots (spots lower than the pebbles) are made. water will sit in those shallow divots and slowly discolor the grout over time. not as big an issue w/those flat pebbles. i had the natural pebble rocks and made the mistake of creating a divot, even though I tried to wipe evenly.
if you place a level on the tile floor, you should not have any low spots between grout/pebble.
this is an example of a beautiful sliced pebble floor. can you see any grid lines? nope. look around the drain. you should not have large grout spaces. he will have to hand place the rocks one by one and possibly cut them to make it properly fit around the drain.show your tile guy this shot. ask if he can do it like this w/no visible grid marks,
like they did on this onethey also grouted in the joints between floor/wall. that's a bit NO.
tell him ahead of time you won't pay if you can see grid marks. make sure you get it in writing. just search the horror stories of bad tile jobs w/pebble tile on here and you'll see what I mean.
also, verify the waterproofing system to be used and if he's doing the floor before the walls. You can get a cleaner looking edge finish if he brings the tile down on top of the pebble floor. (no grout in the joints. 100% silicone caulk to match your grout color). I know,,,a lot of info. just trying to save you woes.
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