Rising damp is a condition where moisture from the ground moves upward through the walls of a building. This occurs when the damp-proof course, a barrier designed to prevent moisture from rising, is damaged or absent. As a result, water can travel through porous materials like brick and mortar, leading to damp patches on walls. The presence of rising damp can cause various issues, including mold growth, peeling paint, and structural damage. It is often identified by a musty smell and visible stains on walls. Addressing rising damp typically involves repairing the damp-proof course and improving drainage around the property.