Tiling over painted wall

[lefty32]

I am going to tile a lower portion of the walls in my bathroom. (The walkin shower and tub already have tile.) The walls have a "knockdown" texture to them and are painted. (The texture is kind of like orange peel but not as pronounced.)

1. Must I get all the paint off the walls or just rough them up pretty good? The paint is tight.
2. If I must get all the paint off the wall, what is procedure?
3. What is the best thinset for this application?
4. My bathroom has good ventilation. Is drywall good enough for the backing?

Thanks for your help. This forum was very helpful for me when I rebuilt my walkin shower using Schluter. Despite nothing was square and plum it turned out good. (It pleased my wife). I added a big bench and two niches, thanks to the assistance of the forum.


Lefty

[kevjob]

rough it up for adhesion

versabond is good

non wet area correct?

[lefty32]

Correct, non wet area. All my wet areas, walkin shower and tub, have tile.
This is just the remainder of the bathroom walls, lower portion only, about 40 inches up from the tiled floor.

Lefty

[Trask]

I have another way of looking at this having dealt with it twice now on showers I was kerdi'n ( the drywall guys mudded and painted the enclosure)
It seems to me the paint in most cases helps the thinset bond..especially latex. If you rough it up you get into a bunch of exposed gypsum mud and thinset and gypsum tend not to work as well together. I think I would key thinset into the painted texture with the flat side of the trowel...let it cure as a bondcoat if possible, (that will help take some of the variation out if it's a bit too textured) and then tile. I've done this with kerdi and tested spots on the wall. I know your bond is only as good as the paint, but in my case it bonded very well.

Just a thought.

[Davy]

A high gloss paint may act different but I tested a piece of tile using Versabond over flat latex paint and it made a hole in the sheetrock the next day when I pryed it off.

[koihito]

Unless your paint starts peeling, I wouldn't be concerned.