I have been helping some friends prepare a room for painting..dampish wallpaper came off really easily suggesting damp, flaky paint underneath, there has been a suggestion to paint the wall with pva to stop the flaking before repainting..I have sanded all flaky paint off and personally feel that after letting it dry thoroughly, lining paper would be the best bet..any suggestions..I'm training as a painter decorator and dont want to make a big mistake!!??