Advice/clarification needed on preparing walls prior to tiling. - Tile Advice

[Donna1971]

Hi everyone, I need some clarification on wall prep before I begin tiling. I have tiled three rooms before over the years, but didn’t realise how much of a Pandora’s box tiling the bathroom would be! I have been looking on this forum for answers for a couple of weeks, there are lots of very informative posts, but as some replies are different I thought it best I do my own post.
The bathroom hasn’t ever been changed since we moved in 30 years ago, except for me painting the tiles. I have removed all the tiles from the wall, most come off with no problems at all, some seem to have been stuck with industrial strength cement, and I damaged the plasterboard ( by the bath) Removing the tiles has revealed painted walls, and some sort of wooden box ( hiding pipes)which seems to be glossed. I was going to replace the damaged plasterboard with a hardiebacker board, but it seems very heavy and I had visions of it with the tile weight damaging the stud wall!
I want to know have I got to remove just the paint, or the paint and the thin plaster skim that is on the plasterboard before I can prime? And should I just replace the damaged plasterboard with a waterproof one or go with the hardiebacker? The tiles are 60x30cm 6mm thick porcelain tiles.
Sorry for the long post, thank you for taking the time to read through. I have taken photos, hope they are okay.

 

[Waluigi]

Depending on tile weights, if it was me then I’d rip every single bit of plasterboard off the walls and re fix new plasterboard. Tank the plasterboard in the wet areas or use a waterproof board like Wedi, Marmox, Orbry etc.

It’s probably two days labour and under £100 materials to have perfect walls. A little more for your tanking, tile backer board.

I’d also use the opportunity to get the walls 100% flat and Plumb.

 

[Donna1971]

Thank you for your reply. Whatever I do, it always ends up being a bigger job than I want it to be, lol! I was hoping that I could salvage something with the other walls! I’ve only ever put one piece of plasterboard up years ago in the front room, that was years ago, and I had help then. Would I have to skim the walls before I tiled if using the waterproof board?( still paranoid about the weight of the hardiebacker)

 

[White Room]

No need to skim the walls if using waterproof boards.

 

[Waluigi]

Which tile size and material are you going for?

 

[Donna1971]

The tiles are porcelain, 60x30 cm and are 6mm thick.