We recently bought a house and a small guest room has a vaulted ceiling that was wallpapered probably 20-30 years ago. Since then, it has been painted white. Now the seams are starting to sag & the ceiling is looking old. What are some good fixes for this? Should I try tearing down the wallpaper? Plaster over the wallpaper & paint? I don't know what to do! I basically just want a simple, smooth, clean looking, white ceiling.