Bathroom Wall. Plaster vs Plasterboard

[melkor]

Hello, I'll soon be doing a small bathroom install for my mother in law.

Currently in the process of doing my research and I have a query for the walls. The room is on the ground floor. Two walls are external and the other two are brick walls. All have a base coat, a skim of plaster and were tiled bottom to top well over 10 years ago. Some photos are below.

I haven't stripped off all the tiles as yet just those around the new window install but if walls are sound, is it advisable to just reskim and then tile or to install plasteboard. I'm particularly interested in the shower/bath tub area, as I have read an aqua/concrete based board is recommended but have been unable to find its merits against plaster. The bath tub will be nestled in against 3 of the 4 walls.

Any guidance is much appreciated.

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[23vc]

If existing plaster is sound, you can tank it above the bath and within the shower. google shower waterproofing kits.
Hacking off completely and replacing with cement board is theoretically even better, but if you’re tanking anyway then the substrate shouldn’t ever get wet even if the tiles fail.

 

[23vc]

but have been unable to find its merits against plaster

It doesn’t disintegrate if it repeatedly gets wet, but see above

 

[melkor]

Thanks for your help. Once the tiles are totally off and I can assess the wall quality fully I'll likely reskim if all is well. For the tiling I will be refering to this comprehensive thread.

 

[Gerrydelasel]

FYI you can tile on top of tiles.