ᐅ Is the surface ready for new wallpaper?

So, we want to renovate the kids’ room and have already started removing the old wallpaper. Since it was quite old, there were multiple layers of wallpaper, and while pulling it off, some of the plaster or whatever you want to call it also came off.

Now the question is whether we should remove everything and then wallpaper, or if we need to apply something beforehand.

You can’t really leave it like this because there are a few millimeters (inches) of difference in the surface, so I think everything needs to be removed. But the substrate is kind of sandy—should we apply a primer first, or what is the usual procedure? I don’t want to replaster it now... this isn’t supposed to be a big project, "really"... I’ve attached a picture to show what it looks like.

Can nobody help me?
The room was actually supposed to be finished by Christmas 😀

Hello, remote diagnosis is difficult, especially since the picture doesn’t provide much information. I would recommend smoothing out the plaster joints over a wide area, letting it dry, and possibly sanding it. Then, prime everything. You might also consider filling the entire wall. If the plaster is too sandy to apply filler directly, prime it first.
Regards, Thommi

Hello Bunny!
Well, in my opinion, the project should really get underway now, otherwise you might face an unpleasant surprise later on, where you’ll think, “I wish I had done it this way…”
I would remove all the wallpaper first, then probably loose plaster and gypsum.
After that, any unevenness and missing plaster layers should be filled with a skim coat and allowed to dry.
Then reapply wallpaper and you’re done.
Best regards 😉

Okay, I did it this way: after stripping the wallpaper, I knocked off all loose material, then cleaned and plastered the surface with bonding plaster. Now it should be ready for wallpapering.

Hello!
Looks like you’ve already been busy 🙂)
In principle, you could now take the next step and start wallpapering the walls.
A tip on the side: especially treat the newly plastered surfaces with a primer. You could also use a very diluted wallpaper paste for this; this method is also possible.
The advantage is that the different surfaces will then absorb moisture better and more evenly.
Best regards 😉