Wall prep for tiling, sealing and tanking

[mikeozz0420]

Hi All,
Already received from good advice from this site.

Having brand new shower installed over existing fitted bath, will be quite a powerful, pumped shower.
Previously the walls all around the bathroom were half tiled from the floor and then painted upwards to ceiling with what appears to be specific bathroom paint - paint is in good condition, no, cracks.

Existing tiles have been taken off and I am in the process of removing the old tile adhesive from the bare plasterboard.

After receiving good advice on this site I plan to prime and tank around the 2 walls where the bath/shower will be.
Have bought specific kit to do this
About 70cms up from the bath is bare plasterboard, the rest of the wall up to the ceiling is painted plasterboard.

How to do i prime/tank the painted areas around the shower/bath?
Do I just prime/tank as with the bare plasterboard?
Is this ok to do on painted plasterboard?
Think it would be impossible to strip the paint from the plasterboard.

For the rest of the bathroom not exposed to water I plan to just prime the bare plasterboard.
I guess there is no point priming the painted part of the walls?
Do I just clean, scribe with stanley knife, sand and clean again?

I`m just doing the prep work to keep the costs down, someone else is doing the tiling.

Appreciate you may say my tiler should know all of this but with the research I have been doing there are lots of different opinions and I would like to canvass these to see what the general consensus is.

Have had this chap do tiling for me before and no issues with his quality of work but not sure he is familiar with suggested current practices, e.g tanking - lots of tilers seem to think that this isn`t even necessary, lots of anecdotal tales of installs done 20 years ago that are still ok.

Any advice appreciated.

Happy to provide any more detail.

Thanks

Mike

 

[angrypirate]

If the paint is clean and stable, then yes just tank over it.

With regards to priming, the one I use doesn't require a primer before tiling but id check the instructions on yours.

Yes, prime the painted, untanked areas.

I would of course run it past the tiler, as if any of it fails it could be blamed on your prep work.

Tanking/priming doesn't take long at all, and id leave that part to the tiler tbh. Just strip it all back and clean what you need to, then hand it over to the tiler imo

 

[mikeozz0420]

If the paint is clean and stable, then yes just tank over it.

With regards to priming, the one I use doesn't require a primer before tiling but id check the instructions on yours.

Yes, prime the painted, untanked areas.

I would of course run it past the tiler, as if any of it fails it could be blamed on your prep work.

Tanking/priming doesn't take long at all, and id leave that part to the tiler tbh. Just strip it all back and clean what you need to, then hand it over to the tiler imo

Thanks angrypilot
You advice is much appreciated.
Mike