Floor tiling mistake?

[Cha0s]

I was in Wickes looking for WBP to use as the under floor for the bathroom. They did have any but did have water resistant chipboard.

I have since read that chip (****) board is not a good option for this use case.

The toilet pipe height was set based off this floor height plus tiles, adhesive and some kind of uncoupling membrane.

So, is my only option to pull up the chip and put 18mm ply down? And nowhere seems to sell WBP anymore, is that an outdated term? Am I just looking for marine ply now?

Thanks.

 

[foxhole]

Replace with cement board , far more stable.

 

[Elsa TLC]

I always use a good grade 18mm marine ply

 

[simplesteve]

With ‘Foxhole’ on this one - Cement board all day long on a floor. Hardibacker comes in 6mm and 12mm. Either/both combined with varying the notch size for putting it down gives you any height you need.
There’s no place for ( possible delaminating) ply in a bathroom these days

 

[Cha0s]

so 6mm hardibacker (or similar) ontop of the chipboard?

 

[Cha0s]

I just want to check I'm getting all the layers down that I need. I don't want the toilet to flush uphill

I currently have the dreaded chip. 18mm.
I'm thinking I need to add:
Hardie + adhesive and screws.
Uncoupling membrane+ it's adhesive (or do I not need this with the hardibacker)
Then my tile and adhesive.

Thanks

 

[ree]

OP,
Why not post pics showing the bathroom floor - & the soil pipe you've referred to?
Presumably, you will also have a shower tray, and a Ped or vanity basin?
A rad or UFH?

 

[Cha0s]

@ree indeed that would be helpful.

So.
This is the general layout.
Bath (shower bath) will go where the vac is. Door is being closed up and a new one made directly in front of the soil pipe.
Hot and cold feeds have been brought up in the middle of the bath area since I'll be putting in concealed controls for shower and bath.

Another view of that area.


This was before the flooring was put down and after the plumbers had been to sort the:
Bath and sink waste, toilet soil pipe and re route some heating and hot water that were above floor level where the toilet is going.
The basin and bath waste were not put in to my liking, i.e. there was an uphill section near the towel rail, but i remedied that situation before putting the floor down.

Here is the toilet, its on some scraps of 18mm chipboard to simulate additional floor height in this pic.
And round the back you can see that the soil does line up, and that it does have some play in it since I havent yet made good.
Going for a concealed cistern fyi.

Toilet on scraps of 18mm chip:


View of the toilet area:
The new door is directly behind where this pic was taken.

Soil pipe through the wall:


Hard to see / photo properly but this is the view back from the pipe under the pan.

 

[foxhole]

You can always go higher with toilet pan and use an offset pan adapter which gets you another 10mm or so.

 

[ree]

OP,
Thats a very clean & tidy site, well done.
You seem to have covered most things &, as you are aware, FFL is important for all fixtures & thresholds.
When you box-in the cistern make certain that you have easy access to the supply shut-off, and can easily open up the boxing.
Keep all wet pipes under pressure - when installed constantly flush the WC before closing in.
The window - the bath - the shower and the enclosure: do you have them in hand?
Same with the electrics & extractor?

 

[Cha0s]

Thanks. Much appreciated.
Yeah I'm trying to keep it tidy
At some point I'll figure out some system to be able to open the top of the cistern enclosure.

I haven't got all the things yet.
Window is in. Tiles are standing by.
Bath and shower screen not yet purchased but got all the taps and whatnot.

Regards to the floor.
I think 6mm Hardie as mentioned above. Fixed down with adhesive and screws. No decoupling membrane but top quality BAL flex one. Only need 2 bags to do wall and floor.

Hopefully that works out.

First I have to fit a new door liner and frame up the old doorway to become the shower end of the bath.