I almost never recommend painting wallpaper, so I am writing this for all those people who absolutely need to paint wallpaper. If there is no way around painting wallpaper, it must be painted following proper processes or you can have massive failures with wallpaper bubbling or pealing off the walls.
Wallpaper Painting Process:
- Cover and protect all trim and floors with masking materials and drop cloths
- Cut out any loose wallpaper
- Use an oil based primer to paint over wallpaper. (This can be very smelly, but this oil base primer is what prevents the water base top coat from bubbling the wallpaper.)
- Once the primer is dry, patch all wallpaper seams and imperfections on the surface.
- Re-prime all the patched areas
- Caulk the wallpaper edges to the trim and ceiling
- Apply two coats of quality finish paint
Whenever possible try to remove wallpaper before painting. Painted wallpaper can de-laminate over the years and become a problem. This wallpaper painting process should only be used when all attempts to remove wallpaper have failed.