call them back that should be under guarantee!! i never use ply for bath panels i use wedi/marmox type boards.waterproof and wont warp ideal for these situationsHelp please: the tiles are beginning to come off my bath panel, which was installed as a new bathroom a year ago. The grout started to crack after a only a couple of months. The tiler insists that he used flexible adhesive and that it is due to movement of the bath panel. Is he correct? What can be done to avoid this happening? Would be grateful for any advice. Thanks.