Sign of damp
Peeling and bubbling paint
Small blisters or large soft bubbles in the paint, sometimes with water or white powder inside. Around them the paint flakes, curls at the edges or peels away in sheets, often exposing putty that has turned soft and chalky.
What it might mean in a flat
Blisters, flaking and lifting paint film.
Paint does not usually fail on a dry wall. Bubbles in a fixed spot, and especially ones that return after repainting, point to water reaching that spot from somewhere. Where the bubbling sits tells you a lot: low on the wall suggests rising damp or a floor-level leak, near a tap or a mixer suggests a concealed pipe, and near the ceiling of an outer wall suggests rain entry.
Common causes
- Moisture behind the plaster pushing out through the paint film as it tries to evaporate
- Salts crystallising under the paint and lifting it from behind
- A leaking concealed pipe or bathroom floor on the other side of the wall or on the floor above
- Rainwater entering through cracks in the external plaster or around a window frame
- Paint or putty applied over plaster that had not dried out after an earlier leak
What an inspection checks
How we confirm it.
- Meter readings across the bubbled area and in a grid around it to find where the damp is strongest, compared with the dry reference wall
- Thermal scan of the whole wall, because damp often extends well beyond the visible bubbles, with every cool patch then checked with the meter
- What sits on the other side of the wall or above it: a bathroom, a kitchen sink, a shaft, an external face or a terrace
- Whether the paint looks recent, and whether there are signs of patch repairs in the same spot
When to worry
Signals that it's active.
- Bubbles hold water or reappear in the same place after repainting
- The damp area on the thermal image and meter is much larger than the visible peeling
- Peeling is next to a concealed pipe line, a bathroom wall or a sink, and readings are high
Where it usually comes from
Questions buyers ask
The flat was just painted and looks perfect. Can you still find old damp?
Often yes. Fresh paint hides the stain but not the water. A meter and a thermal camera can show a wet area behind new paint. If the wall has fully dried, there may be nothing to measure, and the report says so.
Will a waterproof paint stop the bubbling?
A coating on the inside face does not stop water coming from a pipe, the floor above or the outside. It can trap moisture and make the bubbling worse. The source needs to be fixed first.
How long should I wait to repaint after a leak is fixed?
Until the wall has dried, which can take weeks to months depending on the wall and the season. A re-scan compares readings against the original ones so you can see whether the wall is drying before you spend on paint.
Not ready to book? Walk the flat with our 10-minute self-check and get a snag list to take to the seller.
Start the Damp CheckFind the damp before you pay for it.
Book a moisture and thermal inspection. Report on WhatsApp within 24 hours.