To put a walk in shower/wet room upstairs?

[Susieblue18]

Plumber says it’s fine as long as the tiler is good but I’ve heard people having problems. Any advice welcome, thanks

We had an upstairs wet room installed for my mum when she could no longer manage the bath. She did not have a shower cubicle due to mobility/access issues so waterproofing the walls and a waterproof sub floor were required, definitely more than just relying on good tiles.