Damp, mould and condensation
Rising dampness is caused by water rising from the ground into the home. The water gets through or around a defective damp proof course (DPC) or passes through the natural brickwork if the property was built without a DPC.
A DPC is a horizontal layer of waterproof material put in the walls of a building just above ground level. It stops moisture rising through the walls. Rising damp will only affect basements and ground floor rooms. It will normally rise no more than 36 inches above ground level (900mm) and usually leaves a 'tide mark' low down on the wall. You may also notice white salts on the affected areas.
Rising damp will be present all year round but is more noticeable in winter. If left untreated it may cause wall plaster to crumble and paper to lift in the affected area.
Check to see that materials such as soil or building materials, have not been left against the outside of walls as this may allow the dampness to go through / around (bridge) the DPC and cause dampness in the wall. Ideally the DPC will be a minimum of 6 inches (150mm) above ground level.
If the dampness has got around the DPC, try removing the materials as this will allow the walls to dry out. If that doesn't work, a damp proofing specialist will need to be brought in to fix the problem. Tenants should ask their landlord to investigate further.
Mould will rarely be seen where there is rising damp (and then only in the early stages). This is because rising dampness carries with it salts that prevent the growth of mould.