Can anyone please help. Had a new bathroom fitted and the tiles are bulging in the shower tray back wall. Can anyone tell me why? They were not bulging when fitted but weeks later they are. Also now noticed that the grout lines in the bathroom are uneven. Some are 2mm apart and some are at least a centimetre apart. I am worried that water is getting behind the wall tiles. How can I confirm my suspicions before this becomes a bigger issue?