In one of the rooms in my house the walls are wallpapered. Underneath the wall is rough and porous (see picture).
My plan is to strip the wall paper and eventually paint it, but research seems to suggest that it needs some kind of treatment first. I have read about skimming, and plastering, which while tricky, I'm happy to have a go at, but I have also read about using "alkali resistant wall primer".
What is the best way to tackle this? I am after a decent enough finish, ideally without spending a fortune, and if possible not too tricky.