......painted walls.......

[ShaunCorbs]

The only thing I can approve of is:
Removing paint,
Overboarding with mechanical fixings.
Let the other tiler take the risk. 😀

Yep that's what I've suggested either new plasterboard or marmox over the top

 

[david mccullough]

the problem with tiling over paint is, how well that the paint is sticking to the wall, a lot of painters don,t prime the walls with watered down paint so the paint then "flash dries" and as the skim sucks the water out of the paint too quickly, and the paint is only sitting on the wall, when i started tiling 30 years ago there was no problem tiling over paint, but then paint was diferent then and tiles were 6"x6" or 10"x6" less than half the weight, so to answer you question get paint off.