Tile size is a question of walls, that being are they flat or are curves, dents and general construction going to cause problems in the finished wall.
- large tiles fitted on un-flat walls cause problems with corners sticking out and catching the light from overhead spotlights.
solutions: repair walls to be flat and strong enough for the given wall size, if not then the impact of the finished tiling will be adversely affected.
2. dents in walls will de-strengthen the wall in general and this will cause problems later on with unwanted cracks and walls that have unreasonable amounts of movement.
solutions: tough one, but in general the wall skin needs to be replaced to regain the integrity of the overall wall.
3. general construction of the wall with regard to the weight of the tiling installed needs to be taken into consideration at the design stage. For example, there is a limit to how much weight a plasterboard wall can actually hold without rejecting the tile and haveing the tile fall.
solutions: in the case of a plasterboard wall there are alternatives that give greater density and thus give a firmer hold on bigger tiles. The type of adhesive also comes into play at this stage and of course, preparation with liquid sealers also adds to the final choice of size and weight of an installation.