We had a new roof done about 7 years ago. There was a damp patch in our small back bedroom which totall dried up after the new roof. We then had the ceiling repaired and the wall and both replastered. We re decorated and it has been fine and dry till we had the walls skimmed to decorate about two weeks ago. There is now a small part of the plaster about 12" wide and 6" high at the top of the wall and onto the ceiling which hasn't dried out fully. The decorator came this morning and said it was a bit too damp to paint so he left. The wall outside is rendered but is dry. What advice can you give me. If it is damp should I get a builder in or ask the plasterers advice. Should I try a de humidifier? HELP!!!