Damp patches on bedroom chimney breast PDF Print Email
Q I have damp patches appearing on the chimney breast in my bedroom. These are towards the ceiling and occur in times of high humidity and rain. However during an excessively heavy downpour in summer (3" in 3 hours) no damp patches. The chimney has had "everything" done do it externally: repointed, all new flashings, capped and many treatments of waterproof sealant. All the tiles and felt around the chimney have been replaced. Internally there is an air brick for ventilation. At a loss to know what to fix next?
A It sounds very much like the problem is being caused by hygroscopic salt contamination as a result of a previous leak. Have a look at Informative Articles 2, 3 and in particular Article 14  titled 'What price a correct diagnosis' on this site. It will probably sound very familiar and should help explain what is happening.

 
Contact Peter: Email - info@dampdecay.co.uk - Telephone: 015242 71794