Rising damp occurs when ground water travels up in a capillary action through porous building materials such as sandstone, brick and mortar, much the same way that oil travels upwards through the wick of a lamp.The height of the rise is typically around 1 meter high and very rarely rises above 1.5m.
Rising damp can generally be identified by a characteristic "tide mark" on the lower section of affected walls or bubbling/flaking paint.
Penetrating damp is typically caused by water leaking through the building structure.
Water penetration is through horizontal and vertical movement rather than by travelling upwards like rising damp.
Penetrating damp often shows up through damp patches on walls, ceilings or floors, which may darken when it rains.