Both painted and bare plaster allows for the installation of tile.
Tile over plaster walls.
Scrub the wall tiles with diluted degreasing cleaner and a nylon scrub brush.
Adhesive grout and tile 20kg max weight onto plaster.
Or flatten walls with a latex modified skim coat product.
You may tile over existing tile painted or unpainted drywall plaster and textured walls.
Don t use paint glue pva wall paper paste only use the primer recommended by the adhesive manufacturer of your chosen tile adhesive.
Add a diverter and shower line in the wall.
However tiling over tile can add quite a bit of thickness so make sure your wall can handle the weight.
You would have to remove the plaster and replace it not with drywall run from a contractor who says that.
Mold does not grow on cement.
If plaster is any way compromised you should tear out to studs and start over.
Mix degreasing cleaner with water in a bucket using a dilution recommended by the cleaner manufacturer.
That is true you cannot tile over plaster if that s your plan.
Testing the wall for durability.
Loose paint must be scraped.
Also now it s been plastered you will be restricting yourself to a tile with a max weight of about 16 kg m2.
Bring plumbing to code.
Not all plaster wall surfaces will support the tile properly.
This was back in the 80 s.
The problem otherwise is that grout is porous and any slight crack will cause moisture and mold on any other surface.
I have repaired tile jobs that were over 20 years old that the tile was applied directly to regular sheetrock and plaster walls.
If you re not sure if you have lead paint test kits are available.
You should not tile over wallpaper glossy surfaces lead paint or plywood.
Then rinse the wall with a water dampened.
It used to be very common to put tile up on whatever the wall was and seal the the tile.
Follow manufacturer instructions to a tee.
Cover with cement board tape off.