I want to remodel my ugly bathroom and need help. I own an American foursquare built in 1906. The bathroom walls are plaster on lathe; the previous owner put wallpaper on the upper half, and the lower half has what I believe are thin plastic tiles that were painted-over. I peeled a portion of the wallpaper, and uncovered another coating (paper?) which is glossy and is separating from the plaster. Do I need to remove this coating to get to the bare walls? I want to put ceramic tile over the entire length of the wall in the shower area, but I want to leave the wall intact. What do I need to do to the wall to prepare it for tiling? Do I have to remove the plastic tiles? What is the best product to use? I plan on putting up wainscoting over the plastic tiles on the other areas of the bathroom. Can I do this without removing the plastic tiles?