Part tile part plaster…

[G and J]

Our new build will have three bathrooms, each with a mixture of fully tiled walls, plastered walls, and part tiled part plastered walls.

 

The very highly recommended chap doing our plastering has advised us not to try plaster on tile backer boards.  
 

So how do we do the part and part walls.   We are using some big tiles (1200mm x 600mm) so plasterboard, we are reliably informed, isn’t strong enough.  So do we have a split wall - plasterboard on the top half and tile backer on the bottom?  If so is the join best placed under the top edge of the tiles?  How do we ensure that the levels work?

 

Any other suggestions?  We can’t be the first people to do this!

[Russell griffiths]

The cement faced foam core boards can be skimmed, but you use a specific primer. 
definitely not pva. 

[Nickfromwales]

2 hours ago, G and J said:

so plasterboard, we are reliably informed, isn’t strong enough

Hmmmmmmm.

 

So, here's the facts  

 

Stud walls for bathrooms should be at 400mm cc, not 600mm. The weight per m2 is the concern, but if your tiles are that big then......so what? It's still exactly the same kg/m2 as you putting 100x100mm tiles on. If the tiles you bought are 30kg/m2, then so will tiles 25mm x 25mm be. It's physics.

 

Where you apply the math is the board and the way its fixed, so you'd be going for 12.5mm MR PB (if I was doing it) and then screwing it to studs at 400mm cc, and having a screw into the PB at every 100mm max cc. Then you could patio slab the damn walls. If you have studs at 600mm cc then you (or I) would then be installing horizontal noggins to create 400mm cc horizontally. This would give you boxes of 600mm x 400mm which you'd then divide the installed weight of your BFO tiles, per that exact amount of area.

 

You've not been reliably informed.

 

I've been sticking BFO tiles to bathroom walls for 3 decades, and not one's fallen off....yet. I've always used plasterboard, and always gone bat-shit crazy on studs and screwing the MR PB to them. Then I tank the shit out of everything, to the point people think I need help, and the results speak for themselves.

 

No need for fancy XPS boards, cement or tile backer boards, all just stuff introduced so it can be sold to folk to turn a profit.

 

"No".