I have damp in my bedroom wall adjacent to external chimney breast ( there may be more behind the adjacent fitted wardrobe). It is much more obvious when it rains hard onto that side of the house. The outside of the house (1930s) is cement rendered. I have had a man look at the roof and guttering but he can see no problem. Can you advise on potential causes and the nature of the tradesman I need to get to come and take a look
