This is rather late, but thought I'd through in my two cents worth. I am a restoration/preservationist/interior decorator/artist...with 17 years in the field. I do all faux finishes, tromp l'oiel, archetectural detailing, etc ...I have seen ceilings in all sorts of disrepair, including many after the loma prieta earthquake in San Francisco/Oakland CA. If the slip coat of your plaster ceiling is falling off, there is a serious problem with the plaster, anything you place over it will have that as its weak link. Those areas need to be taken down to the brown coat and re-slipped. If the plaster is still intact, I would recommend using a "blank stock" or "wall lining" material, use the fiberglass reinforced type, a little more expensive, but very strong. I've used blank stock over plaster ceilings that had to be fastened in place with ceiling buttons, plastered over, blank stocked, and then papered with Bradbury and Bradbury wall paper. If you know Bradbury papers, you know you don't want to ever have to redo them...I used up to 22 different papers in a quilt like design, so the ceiling may never be repaired if damaged. These ceilings with the blank stock over plaster, have not only survived earthquakes, but are stronger than ever before. The blank stock can be painted, textured, wallpapered...whatever. The best of these products I have used came out of Santa Rosa, California and named "for your Bear Walls", sorry, I don't have an address or phone number...call Mark's paints in Alameda..(510) 522-0717....good luck!!!..I just had another thought, at the turn of the century (1900's), decorators often used canvas glued over plaster, then painted or papered..