tiling on wood

i have an exposed edge on my shower cubicle stud wall its is part aquapanel part timber and part plaster board
I intend to cover this with a slate mosaic (3cm square) can i tile straight on this (using single part flexible bal) or should i skim it first?

What type of timber is it,ply?studding timber?
Prime it with acrylic primer then tank or if possible board over with 6mm backer.

err - its outside the shower area - its the edge of one of the stud walls that makes up the cubicle. I cannot clad it in any way otherwise it will hinder access to the bath. I therefore intend to finish it with decorative mosaic - it will never get wet (EVER!)

the wood is "studding timber"

if you can try and imagine a cross section of the stud wall you have tile edge then plasterboard edge then stud timber then aquapanel edge then tile edge. The whole thing is about 8cm thick and 2.1m high.

wish i could explain things better

lymmranger said:

err - its outside the shower area - its the edge of one of the stud walls that makes up the cubicle. I cannot clad it in any way otherwise it will hinder access to the bath. I therefore intend to finish it with decorative mosaic - it will never get wet (EVER!)

Click to expand...

Wanna bet; even though it’s outside the wet area, it will still absorb moisture, expand & there go your tiles. By skim I assume you mean plaster? Don’t, it’ll fall off.

You could try sealing it with a WP1 but that’s going to work out a very expensive strip of tiles. Epoxy based adhesive & grout would be waterproof but, again, that makes for a rather expensive strip of tiles.

A waterproof SBR sealer might help but I wouldn’t like to guarantee it over any length of time.

oh wonderful!

.......this bathroom is turning into a nightmare - it would have been cheaper to rip it all out and start again.
This all started with a "simple" replacement of a cracked shower tray, with all the other items remaining unchanged. Trouble is they put the tray in first and built the rest of the bathroom round it - hence the new stud wall. Previously the offending edge was just tiled onto the wood and this was still sound when dismantled.
However the forum generally frowns on the practice of tiling on wood hence my question. I may just have to risk it