Rising damp is moisture that comes from the ground and gradually rises through porous materials (stone, brick, concrete blocks). It most often appears at the base of walls, both indoors and outdoors, with marks that follow the bottom of the masonry rather than isolated patches.

Typical signs include: continuous tide marks near skirting boards, crumbling plaster, blistering paint, peeling finishes, deteriorating mortar joints, and sometimes whitish deposits (salts/minerals often called “efflorescence” or “salt deposits”). The wall may look “heavy” or saturated and show regular marks up to a limited height, usually developing slowly over time.

This page aims to help you identify the key indicators of rising damp and avoid confusing it with other forms of moisture. For example, water ingress is often more localized (a concentrated stain), while condensation tends to appear on the surface, especially in colder or poorly ventilated areas.

You will also find the essential concepts to understand the phenomenon: capillary action, wall porosity, salt migration, and the visible effects on plaster finishes. Finally, the page outlines the main families of solutions used when moisture is linked to rising damp, including non-invasive wall drying approaches and polarity inversion moisture control devices.