What's the difference between rising damp and condensation?

These are the two damp problems most often confused with each other, and the confusion is expensive: their treatments have nothing in common.

Rising damp

Groundwater drawn up through walls by capillary action. It only affects ground-floor walls, rarely rises above 1 metre, and leaves tide marks and salt deposits. It's consistent year-round (though it can look worse in winter) and is a building-fabric problem: the damp proof course is missing, failed, or bridged.

Condensation

Moisture that starts in the air (from cooking, showering, drying laundry, even breathing) and condenses when warm humid air meets a cold surface. It appears at any height, favours cold spots (external corners, window reveals, behind wardrobes on outside walls), gets dramatically worse in winter, and is the number-one cause of black mould. It's a lifestyle-and-building interaction problem: ventilation, heating patterns, and insulation all play a part.

Why the distinction matters

Injecting a chemical DPC into a wall that's suffering condensation achieves nothing. The mould returns and the money is gone. Equally, fitting extractor fans won't stop genuine rising damp. A proper survey uses moisture profiling (measuring how moisture varies with depth and height in the wall) to separate the two with evidence rather than guesswork. Condensation and mould issues also carry legal weight for landlords under Awaab's Law, where the right diagnosis and documentation matter as much as the fix.