Have you got a bathroom ceiling like this? The local authority put this down the “Condensation caused by lifestyle” but the tenants had their windows open day and night. The nasty looking mould is Alternaria which can stimulate asthma in a child. Not surprisingly the tenants had taken their child to hospital twice with asthma problems. Fortunately, they called DAMP DETECTIVES who located the source of the damp to a point outside the flat and the tenants were moved. If you have any doubts about mould or damp call DAMP DETECTIVES who will always find the source of the problem