Rising Damp Explained:

Moisture bypasses the Damp Proof Course (DPC) and rises up into the walls to create rising damp. Builders will place Damp Proof Course (DPC) horizontally into the wall to specifically stop damp entering into the wall and failure of the Damp Proof Course (DPC) will result in Rising damp. Bricks and plaster suck up moisture just like a sponge and will assist in creating serious rising damp problems. The diagram below illustrates how moisture bypasses the Damp Proof Course (DPC) and results in rising damp.