O
Old Mod
If there is movement and bounce is the builder at fault for not preparing it correctly. Or is the tiller at fault for tilling over something that was not prepared correctly?
Who sourced the tiler?
If Builder then half each, cos I’ll expect he will have been pressured by Builder to ‘just get it down’
If it was you, the tiler should have known better. But then any tiler who lays thin tile that way is not a tiler who’s up to speed with modern practices or techniques and may not even be a tiler at all.
I specialise in thin tile and I spent half my time last year putting bad installs right.
For thin tile to survive the distance it has to be installed correctly, and that isn’t.