Is it normal practice to fit a shower bar type thermostat to the tiles but sticking with mastik. I know there are special nrackets available but out builder reckons sticking it is normal. The reason I ask is that our thermostat has come loose and the plumber has just returned to stick it up again. I caught sight of the pipes inside the wall and they are not screwed down at all. He reckoned that this was the standard thing to do. Also the thermostat drips like mad when switched off. The plumber reckoned the "cartridge" could be changed but it would probably go again. His suggestion was to change the whole thermostat for around £100 - the shower is less than 3 years old !!!!