Can anyone tell me why I can't use adhesive then grout tile on a painted, panelled wall. I have just the area above the tub/shower unit, going to the ceiing(59"x24"). No water spray or contact to create problems, just want an updated look without tearing out walls and putting up the cement back board.
CBU is a stable surface when subjected to temperature changes and moisture, which important for ceramic tile. You certainly wouldn't be the first person to tile over "whatever is there", and it might work, but you also might have tiles falling off the wall a year from now. I would spend a little extra time and money and do the job right.