I live in a house built in 1940. The bathroom is all original, with a walk-in shower, tub, pedestal sink, and commode. It is tiled from floor to ceiling. The only surface not tiled, other than the woodwork, is the ceiling. A couple of months ago I had the ceiling repainted. The contractor sanded the surface, put on a skim coat of plaster, sealed it with BIN, and a coat of paint. After 5 days the ceiling started to alligator and then the paint and skim coat of plaster started peeling off. I waited a couple of months and had the contractor come back and redo the project. This time he power sanded the previous peeling surface, applied a new skim coat of plaster, sealed with BIN and repainted. Five days have elapsed and the ceiling is starting to alligator and peel again. The contractor is at a loss as to what is causing this and is recommending a new ceiling. What could be the problem. I am waiting 36 hours before using the shower. I do not want to replace the ceiling. PLEASE HELP!