tanking a wetroom

[-=HaZ=-]

I'm doing a bathroom at home soon and have done alot of research regarding tanking the room..... The only thing iv not found is with regards to if I have to water proof the full room or just the section where the shower is
The room I'm doing is 21m².... That's walls and floor..... The shower area itself is 1.5m² flooring area then walls


Would I need to tank the full room top to bottom? Or just the area where my shower is going


Thanks

 

[Chalker]

Just tanking the shower area will be fine. Go 150mm past the shower area.

 

[tanker]

tank as much of the floor as possible, i have seen water track over 4m under tiles in a wet room installation.
cheers