You can't plaster over paper. Some plasterers might but I would not do that. Your options are get paper of as hard as it may be, or re-board all walls, which will cost a lot of money. You won't be able to chip plaster off plasterboards, it will damage them so you will then have to re-board the walls. This might not be what you wanted to here but that's your options, hope this helps you thanks. Dan

Hello there. Do not plaster over your wallpaper as the plaster will crack and fall off. You will have to get the wallpaper off or let a plasterer look at it or a painter look at your job to see what he can do with it. Many thanks.
E Mckeown

Is the house skimmed or just tape and jointed? Tape and jointed meaning the joints in the plasterboard are filled only meaning that the wallpaper would be directly on to the plasterboard. if it is skimmed a steamer should do the trick as the steam penetrates the paper but not the skim making it force the paper off, if tape and jointed you are better trying to do it with a damp cloth/sponge but it will be a nightmare to remove, I wouldn't ever recommend plastering on to wallpaper as no matter how u prepare it you are still plastering on to a false background so when the paper decides to come loose the skim will fall off, hope this helps. Scott.

Sounds to me as if there is no lining paper on there, after all you have done it should have come of, so yes I would get a Plasterer round to give you a price and they will advise you on what to do anyway

no sorry the paper needs to be removed for effective plastering to take place