Wet room advice and questions

[Flintstone]

There was some debate about the correct way to do it on here a while ago, but yes with what you are doing, tank on top of the slc as per photo. Once it’s fully dry ofcourse

 

[Garreth]

Thanks for your advice Localtiler. I am apprehensive about applying the tanking on top of the slc I'm thinking that the heat from the matting will warm and damage the tanking solution. As I say I was always under the impression that it should go tanking, then heat mat, then screed, then tiles.

if I do it that way then I will have to make a dam on the line of the shower tray to stop the slc flowing onto the shower tray. I am worried this will then make a step and different levels in the floor which I will struggle to keep the floor levels the same.

the next question I have is I have to replace the current chipboard floorboards as the current ones are rotten. They are 22mm currently but I'm planning to use thinner 18mm ones and then insulation boards to make the level up and insulate the floor.

The question is should I use waterproof plywood for the floor or would normal chipboard be ok/ sensible to use? in theory they shouldn't get wet as the waterproof insulation and tanking is forming a waterproof barrier