Can you plaster over old wallpaper?

[Edinburghnewbie]

We have moved a door and where the new plasterboard meets the original wall - which is covered in several layers of wallpaper. Can I plaster over the seam to make a smooth finish or do I have to wall paper strip the whole wall?

Thanks for any advice!

 

[misterhelpful]

Although sometimes possible, it is very time consuming and fiddly to patch up this kind of alteration and achieve an acceptable result. The fact that you have several layers of wallpaper makes it a lot more difficult. One layer of wallpaper can be stripped back to the edge of a full length, the plaster patched, and then new paper applied to complete the job, but, with several layers, you will never get a patch to be unnoticeable.
Even getting the area patched will involve a lot of effort so the best thing to do is strip the whole wall and get it all skimmed. This will allow the plasterer to apply scrim over the joints, making them less likely to crack in the future. You will also be guaranteed a perfectly flat wall (providing the plasterer is good), with no evidence of a doorway having ever been there.