What Causes Condensation?
Published: 2026-03-12 • Written by Parkside Construction
Condensation handles the majority of damp issues in modern UK properties, especially inside tenanted flat conversions. Unlike rising damp, condensation is entirely airborne.
Relative Humidity and Dew Points
Moisture is suspended in air as gas (vapor). Hot air holds far more moisture than cold air. If hot, moisture-saturated air (e.g. from hot baths, boiling kettles, cooking, drying clothes) meets a cold structural point (like uninsulated brick bay window corners, steel beams, or single glazing), its temperature drops rapidly. Cold air can't hold the gas, and it suddenly turns into liquid water. This temperature is called the Dew Point.
How to prevent it?
Eliminate moisture at its source by keeping relative humidity levels below 60%. Swap simple bathroom axial fans for continuous-running continuous extraction extractors (dMEV), clear window trickle vents to let the rooms breathe, and maintain consistent low background heating.