We're tiling a new ensuite shower area which was plastered 2 months ago, using ceramic tiles with waterproof adhesive. The adhesive sticks well to the tiles, but our problem is very poor adhesion to wall. After 2 days, can easily be lifted off by hand, with no adhesive left on the wall.
The plaster finish is pink and very smooth, but not dusty. The wall has not been sized.
Is it possible that wrong finish plaster has been used, or maybe an additve put in the plaster mix to cause the problem?
I've tried roughing up the surface with course glasspaper and cleaning off, but then still same poor adhesion.