Moisture is the most expensive word in property. It ruins finishes, feeds mould, corrodes structure — and it is invisible on a sunny viewing afternoon.
The four ways water gets in
1 · Rising damp
Ground moisture climbing the masonry where the horizontal barrier has failed or never existed — common in older buildings. The tell: tide marks and blistering paint in a band above the skirting, worst at the bottom, fading with height.
2 · Condensation
Warm indoor air meeting a cold surface — the corner of an outside wall, the reveal of a poorly insulated window. Where the surface stays below the dew point, water films form daily, and mould follows. This is the most common source of black mould in bedrooms and behind wardrobes.
3 · Water ingress
Rain or leaking services finding a path: a failed roof connection, a cracked balcony seal, a corroded riser. Damage often appears far from the entry point — water travels along beams and behind finishes before it surfaces.
4 · Trapped repair moisture
The quiet one. After a leak or flood, walls need weeks of controlled drying before they are sealed and refinished. Skip that, and the renovation locks the water inside — where it migrates to the one surface nobody repainted. A freshly renovated room next to a peeling one is not a coincidence; it is a story. We documented exactly this case →
What to notice at a viewing
- A musty smell that the open windows are working hard against.
- Fresh paint on one wall — or one room — of an otherwise tired flat.
- Tide marks, blistering or peeling paint above skirting boards.
- Black spotting in corners, window reveals, behind furniture pushed against outside walls.
- Dehumidifiers, air fresheners, or furniture arranged to hide wall bases.
What we do about it
Every suspect surface gets measured — capacitive mapping across the area, pin readings at depth, air humidity and surface temperature for the dew-point calculation, thermal imaging where the pattern needs tracing. The report gives you the readings, the probable cause, the remediation route and the cost estimate — the difference between «there is some damp» and a number you can negotiate with.
The Swiss angle
In Stockwerkeigentum, moisture through the envelope — roof, façade, common risers — is usually a matter for the community of owners, paid from the Erneuerungsfonds. Which means one damp patch in your future bedroom can be a question about the entire building’s finances. We read the minutes and the fund statement as part of every survey, because the wall and the paperwork have to tell the same story.