Brian Joseph Lenehan
Hello... It is the lining paper that keeps slightly dodgy plaster together so its fine to paper over but just put a watered down coat of emulsion on the paper first this will show up any loose paper such bubbles or loose edges. Stick down the loose edges, cut out any bubbles and fill the holes. when the filler is dry sand it smooth, then you are ready to paper. A decorating job is only as good as the preparation you put in to it. Thank you B J Lenehan