I've been tiling the kitchen walls and the tiles used on the main walls are quite thick. The ones for the splash back behind the cooker are mosaic tiles - where you get quite a few glass one on one sheet - trouble is they are much thiner that the wall tiles that will be at the side of them.
Since the difference is about 5mm is it acceptable to stick 3mm MDF on the wall and tile directly on to that. I was thinking about building it out with adhesive but i will not get a nice flat finish.
3mm is the thinest sheet material that i can find and no plywood.
Cheers for any help or advice.