Rising damp guide
Rising Damp or Condensation?
Condensation and rising damp can both affect the lower part of a wall, but they behave differently. The most useful clues usually come from where the moisture forms and what else is happening in the room.
Where condensation usually shows first
Condensation forms when humid indoor air meets a cold surface. Window reveals, outside corners, areas behind furniture and poorly heated rooms are common places. Black mould is particularly associated with repeated surface condensation.
How rising damp differs
Rising moisture originates in the wall from below rather than condensing on its surface. Damage to plaster, salts and damp skirting can be more significant clues than surface mould. The wall construction and DPC arrangement also matter.
Why both can occur together
A damp wall is colder than a dry one. That can make condensation easier to form on its surface. Treating ventilation alone may therefore improve mould without resolving the underlying moisture source.
Simple observations before calling anyone
Notice whether mould returns after cleaning, whether the room is heavily used for drying clothes, whether the affected wall is external and cold, and whether there is salt or plaster damage near the floor. These observations help a competent inspector decide where to look first.
Want somebody local to look at it?
If you would rather have the damp investigated in person, you can use our help page to describe the problem and decide what sort of specialist you need.