WC shower tiling and tanking concerns

[masamune]

I am having a small WC with a shower done on the ground floor.

The shower is enclosed from part of the staircase projecting into the room above. Paneledwith fire plasterboard. Left/right and bottom are all ply and the back is just the external wall that will be plastered, with a small window.

In my main bathroom a few years back, they glued a breathable black membrane for tanking on all walls (masonry exterior walls) and then glued the tiles on top of that. This has all been good so far with no issues or leaks.

I talked to the guy preping and tiling the WC about it and he says there won't be a need for tanking/membrane. That will be an extra cost in the work quoted. He is going to use Bal SBR bond primer and Bal flex adhesive. I presume some waterproof grout etc.

This is now a concern, to my understanding I thought it was a matter of course to use tanking when doing a shower or wetroom. At least I would do this for the peace of mind, in case water could potentially leak through the grout and behind the tiles going down to the joists. The house is 1930s with suspended floors.

Urgent advice is most welcome!

 

[Charliesw4]

Hi

It would be beneficial to have a tanking system installed in the wet area, whether a membrane type or paintable type. Mapei and ardex do very reasonably priced kits.

Is there a shower tray?

Charlie

 

[masamune]

Hi

It would be beneficial to have a tanking system installed in the wet area, whether a membrane type or paintable type. Mapei and ardex do very reasonably priced kits.

Is there a shower tray?

Charlie

Good to know that I'm not being unreasonable, thanks for the recommendations.

Yes, there will be a stone resin shower tray to save on floor tiling. Tiles will be finished on top of the tray edges, so that the edges are sealed.

Any potential issues with the above setup?

 

[Charliesw4]

A paintable tanking system is the easiest way forward and only nessesary in the shower area. Mapei kit is around £60 and readily available at screwfix etc.

I definitely wouldn't recommend Tiling directly to ply, I would use either tanked plasterboard or a tile backer board on the walls and (once deflection free) overboard the floor with 6mm Hardiebacker, glued and screwed at 200 centres.

Charlie