Penetrating damp vs rising damp vs condensation

Why it matters which one you have

All three cause damp patches and mould, but the solutions are completely different. Treat the wrong one and you waste money while the problem continues. Here's how to tell them apart.

Condensation

Condensation is by far the most common. It's moisture from indoor air (showering, cooking, breathing) settling on cold surfaces — windows, external walls, corners. Clues: worse in winter, appears on cold surfaces and in poorly ventilated rooms, often with black mould. Fixed by ventilation and humidity control.

Rising damp

Rising damp is ground moisture climbing up through walls at the base. Clues: a tide-mark up to about a metre high, blown plaster, salt deposits, affects ground-floor and basement walls. Fixed by a damp-proof course and re-plastering — not ventilation.

Penetrating damp

Penetrating damp is water getting in from outside through the building fabric — a cracked render, faulty gutter, leaking roof or defective seal. Clues: a localised patch that worsens after rain, often higher up or mid-wall, sometimes with staining. Fixed by repairing the external defect.

Getting the diagnosis right

Because the fixes differ so much, correct diagnosis is everything. A professional mould inspection uses moisture readings and the pattern of damage to identify which type you have and what's needed — so you fix it once. professional mould removal and re-plastering follow where the structure is affected.

Not sure which damp you've got? book a €75 inspection for a proper diagnosis, or call +357 96 738151.