Is that damp patch caused by condensation or rising damp?
They are completely different problems, but they can sometimes look surprisingly similar.
Condensation comes from moisture already in the indoor air and usually forms when warm, humid air meets a cold surface. Rising damp, on the other hand, involves moisture moving upwards from the ground through porous materials such as brick and mortar.
In this video, I explain the clues that can help you tell them apart, including:
where the damp appears
black mould around windows and cold corners
damaged plaster and salt deposits near floor level
the effect of cold weather, cooking, showering and drying clothes
why a dehumidifier may help condensation but will not stop genuine rising damp
other possible causes of low-level damp, including leaks, high ground levels, defective render and rain penetration
The important point is not to diagnose damp purely from appearance. Try to establish where the moisture is actually coming from.
For more practical information about diagnosing damp and other property problems, visit:
https://www.problemhomes.co.uk

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