Can I use Kerdi over plaster in the shower?

[Selene]

Hi All,

I just started a sort of remodel of one of our bathrooms in our 1946 house. I have 3 questions.

The first: We pulled up the linoleum to find some very dated pink floor tile. All the tiles and grout lines seem to be very much intact. I have tried to think of a color scheme so we could keep the pink, but honestly I don't want pink tile. Can I tile over this or would we need to remove the tile first? At this point, I am trying to get the bathroom functioning again with minimal deconstruction.

Question 2: The previous owners had put up a plastic bath surround on the 3 walls of the shower/bathtub, but the glue job was not very good and the panels were seperating allowing water behind the surround. So we have taken that down and the walls behind actually seem to be fine except for a bit of mold that we are killing off with bleach. The walls are plaster with I think a coat of paint. I would like to tile the walls now and wish I had known about Kerdi when I tiled our other shower last summer. So can I use Kerdi against the plaster? I don't want to start tearing out walls and I don't think there would be enough lip in the shower if I put cement board over the plaster. Worst case scenerio is we go back to another form of plastic shower surround, I guess, but tile would be so nice.

Also, the bathroom shares a wall with the living room which has a lot of nice plaster work. I am paranoid that any kind of construction work in the bathroom may lead to cracks in the livingroom. Any thoughts there?

Thanks for your help.

[John Bridge]

Hi Selene, Welcome aboard. Very pretty name, by the way.

Question one: What the heck is wrong with pink?

Yes, you can tile over it, and that is what's recommended. There is a very good mortar bed underneath the pink tiles that you would not want to disturb.

Is there paint on the plaster? If so, You'll be installing the Kerdi over paint. You'll have to know the paint won't let loose down the road. Otherwise, yes, you can intall Kerdi over plaster.

[Selene]

Thanks so much! You have made my day. It sounds like I can move forward and do everything I had wanted to.

The paint on the plaster seems to be very much a part of the wall, so that should be ok... I think. And as for pink...well I like certain variations of it. But in this case, it is just a very unpleasant shade. It happens to be the same color as the shower we demolished and re-tiled (actually because of a leak rather than because of the color) last summer as well as the toilet we removed. Someone liked pink back in the day. I am thinking it was around the 1950's.

Thanks again.

Selene