1. Look at where the stain is
Experts don't guess: they look at the pattern. How high the stain is, whether it's near a window, whether it grows when it rains and whether it leaves white powder. Those four clues are enough to tell apart the three kinds of damp found in homes.
2. Condensation
Misted-up windows in the morning, marks in high corners and behind furniture, mould in the bathroom. It appears in winter and improves in summer. It is the most common kind and the only one where paint really helps, provided it is breathable, lets vapour out and you air the room every day. We explain it in anti-condensation paint: what it does and what it doesn't and, for the typical bedroom case, in mould in the ceiling corner.
Quick clue: if the stain is high up and near a window or a cold corner, it's condensation.
3. Damp rising from the floor
A dark band low down on the wall, up to 60–120 cm, with white powder (salts) and paint coming off in flakes. It doesn't depend on the weather. Here paint alone is not enough: the rising water has to be stopped first. After that, NeutralySalt Primer for the salts and MATE5000 for the finish (details in salts on the wall).
4. Leak or water ingress
Stains on the ceiling or on the outside wall that appear or grow when it rains. First the water is stopped from outside: repair cracks and joints in walls, Cool Roof Therm if it comes in through the flat roof. Painting indoors before stopping the water is money down the drain. If the water comes in from above, follow how to waterproof a flat roof.
5. What to do in each case
- Condensation or mould: clean, Sellador Total L44 if there was mould and two coats of MATE5000; ventilate. All together in the Condensation Kit.
- Rising from the floor: first the rising water is stopped; then NeutralySalt Primer to hold back the salts and MATE5000 as the finish. There is no kit for salts: we advise you case by case in salts on the wall. If the band is higher than one metre, send us a photo first.
- Leak: stop the water from outside (repair the wall, Cool Roof Therm on flat roofs); once dry, Sellador Total L44 as a primer and MATE5000 indoors. These are the same products as in the Condensation Kit.
- Not sure: send us a photo. It's free.
Guía escrita y revisada por el Equipo Humix Paint con los datos de las fichas técnicas de cada producto. La pintura actúa en la superficie: si el agua sube del suelo o entra de fuera, primero se trata la causa.
