I noticed, too late (during install), that the mosaic tile my wife chose for accent in our shower is a different depth than the regular tile we're using. The mosaic tiles are about 1/8-3/16" thinner than the other tiles. I tried using a piece of backer board, but that made the mosaic tiles push past the regular tiles. I wound up trying to build up using thicker glass mortar, but that resulted in less-than-perfect mosaic...so I need to rip this out.
My question is...how should I build this up so I don't need to make a thick mortar base for the mosaic? Should I built it up slowly with layers of mortar? Is there some thinner material I can use to build this up in this (wet) environment?
If the mosaic accent tiles are thinner than the field tiles, I think building up extra thinset behind the accent tiles and carefully pushing them into it so they are flush with the surrounding field tiles is a decent approach.
If the mosaic accent tiles are thicker... I don't have a good solution for that. That is the situation I had in my shower and I just have a bit of a lip that is grouted. The transition is not too bad.