I've just finished an internal extension to a bathroom by shifting a stud wall. I've finished the wall on the bathroom side with waterproof 10mm tile backing board. Very easy to work with, and all set, ready for tiling.
However, I've had a tiling rethink, and no longer want to tile to the ceiling. This would leave the tile backing board, which will need finishing with a smooth surface. I don't want to go to the bother of a plasterer.
What would be a suitable material to use? Something thinner than the tiles - say less than 10mm.
Or is it going to the best/easiest to cut away the non-tiled sections and use some water resistant plasterboard? This would involve wasting some of the tile backing board, but hey.