12mm tile board + skim plaster (no tiles) in front of Geberit Wall Hung WC Frame?

[Poogle]

Hi folks!

 

So I have a very small shower room, but I'm installing a Geberit 8cm wall hung WC frame in a false stud wall.

 

In order to keep the loss of room width as small as possible, I'm aiming to use 12mm tile backer board (Abacus) tight to the front of the frame, and then skim plaster. Then no tiles — just a two-part epoxy marine paint over the plaster (with a couple of layers of sealant first). The shower area will be fully tiled.

 

The minimum finished depth in front of the Geberit frame is 10mm, according to the installation manual, and Geberit technical support.

 

My question is: Is this enough to support the force of the wall-hung WC pan (and the person sitting on it), at the rear bottom of the WC? I have read that 85% of the weight is taken by the metal mounting studs, and acts straight down; but 15% is a "turning" force on the wall, where the rear bottom of  the WC pushes against the wall.

 

Could that crush the plaster, and the tile backer board behind it? I'm going be sure to have the board tight against the frame; and I'm going to use a hardwearing plaster: ThistlePro DuraFinish.

 

It's the force of the WC pan that concerns me. Plus I don't really want to use HardieBacker board for a number of reasons.

 

Any advice would be very welcome!

Edited September 4, 2018 by Poogle

[nod]

If you build your stud out of 100 mil x 50 studs Set either side of the frame at 400 centre Its also worth fixing 18 mil ply on the bedroom side to make a very strong and ridged wall

 

If you paint the cement board with two coats of SBR It will be ok to skim the following day 

 

 Hope this helps

[PeterW]

The issue with any of the frames is the twist on the frame rather than the crush effect by the pan. Ideally you need to double up the studs either side or as @nod said, ply the wall behind. 

 

Tile backer board tends to be cement based - you will not crush that or the plaster on the front of it as the compressive load is very low in reality.