The walls of my shower are being tiled, and we have two types of tile. The main one is about 10mm thick, then every so often there is a strip of a smaller mosaic tile about 7mm thick. Am I being unreasonable in expecting them all to be fixed such that their surfaces are flush, i.e. the adhesive behind the thinner tiles would be built up by an extra 3mm or so? It seems so obvious that I didn't mention it specifically to the tiler but I wonder if this is the accepted way of doing things. Apart from anything else I'm interested to see how he will grout between the 2 differing levels.