Part of Ward Property Services UK LtdCondensation forms when warm, moisture-laden indoor air meets a surface below its dew point. Everyday living produces a surprising amount of water vapour: cooking, showering, drying laundry indoors and even breathing can add well over ten litres of moisture to a home each day. When ventilation cannot remove that vapour, it condenses on cold windows, external corners, behind furniture and inside wardrobes.
Modern draught-proofing has made this far worse. Replacement windows, loft insulation and sealed chimneys all reduce uncontrolled ventilation without replacing it with controlled ventilation. Our approach is to measure rather than guess — we log temperature and humidity, calculate dew points, test existing extract fans for actual airflow and then specify the minimum intervention that will keep relative humidity in the safe 40–60% band.
Common signs
- ✓ Water running down windows and pooling on sills each morning
- ✓ Black mould in corners, behind wardrobes and around window reveals
- ✓ Damp, musty-smelling clothes in built-in cupboards
- ✓ Cold external corners that feel wet to the touch
- ✓ Problems that appear in October and disappear in spring
Likely causes
- • Insufficient or non-functioning extract ventilation
- • Drying washing on radiators without an extract running
- • Unheated bedrooms and intermittent heating patterns
- • Cold bridging at lintels, reveals and wall-floor junctions
- • Blocked trickle vents and sealed-up airbricks