Quick question, so the job I am on right now with the boss had new ceramic tile laid on top of an old ceramic tile floor that was very stable. Anyways the HO about a week latter had a basement waterproofing company come in to do some work. The next couple of days latter the floor where they had been walking starts to show cracked grout lines and tile starts to feel louse when you walk on it. So we start to cut the grout and remove the lose tile. When we did this it looks like the thin-set was fine because it covered the whole back of the tile. My question is could the tile become lose just because of all that weight on the tile and the constant movement and weight put on it or was our thin-set tile install at fault?