Hi, i need to hang new batrhoom tiles above my bath to create a tiled shower area. I've replaced a load of blown plaster, but the rest of the wall still has old paint on, much of which is flaky. I've scraped off the loose bits, but do i need to remove it all? I will be tanking the wall anyway. Read more: https://www.diynot.com/diy/threads/tiling-over-old-flaky-paint.591614/#ixzz7TAoFWTyT
Best to remove as much paint as possible, as your adhesive bond will only will be as strong as the paint it's stuck to. Any paint that is well adhered can probably be left, but scoring the area will improve adhesion.