We don’t recommend it if you want the best possible result. Old wallpaper can loosen when new adhesive is applied, causing the new wallpaper to lift or bubble. It can also be difficult to achieve a smooth, even finish.
For a flawless result, we advise removing the old wallpaper first and applying the new one on a clean, flat, and smooth wall. This ensures your new wallpaper adheres perfectly and looks its best.