Wet Room - Subfloor? Walls?

[Synforge]

Hi guys,

I've read around so much on this and there seems to be a lot of opinions on this, some pictures to start off with:

IMG_20180717_210848252

• Synforge
• 17 Jul 2018

IMG_20180717_210916166

• Synforge
• 17 Jul 2018

IMG_20180717_210925680

• Synforge
• 17 Jul 2018

I'm now in the process of figuring out what to do with the walls and shower tray/floor.

I'm wanting to put in a shower tray former, however the surrounding subfloor is P5 chipboard and I'm wondering whether I should take this out and put something else in that is a little more water resistant? (More of it has to come up anyway to put the waste in, and since it's glued it definitely needs replacing).

Additionally I don't know what to use for the walls with various people saying a waterproof board like Wedi is the best option, while others promote something like Hardibacker.

So what would you do in my situation?

 

[John D v2.0]

I'd use plywood for the floor as it's less affected by water. For the walls I'd use cement board with the joints filled but I'm not sure the differences with wedi. If it's a wet room you really have to tape and seal the joints well, also fix everything well to avoid movement.