If you're looking for which paint to choose for a damp wall, read Anti-damp paint: what it really is and how to choose.
Breathable isn't the same as waterproof
In construction, calling a paint breathable describes its ability to let water vapour pass through. It doesn't mean the wall breathes like a living thing, or that the product automatically makes existing damp disappear. Nor does it mean letting rainwater through freely: liquid water and vapour move by different mechanisms.
The physics of diffusion
Vapour moves by diffusion when there's a difference in vapour pressure between the two sides of a material. The rate depends on both the gradient and the properties and thickness of the layers. The Whole Building Design Guide explains that different coatings have very different permeances; that's why it matters to look at the whole wall build-up, not just the paint label.
Pared Seca
Breathable, damp-resistant and anti-condensation. It lets water vapour out of the surface instead of trapping it.2 L DoyPack · 12 colours · 10–12 m²/L per coat
How to interpret the risk of trapped moisture
If a substrate holds water and is covered with a low-permeability system, its ability to dry towards that face can be reduced. In old walls with salts, Historic England documents damage when crystallisation happens behind relatively impermeable coatings. However, increasing permeability doesn't on its own fix a continuous source of water: the cause has to be removed first.
What to check before painting
Check whether the surface is mineral or synthetic, whether there's flaking, dark stains, efflorescence or active damp, and whether previous coats are well bonded. A spot sample and a professional assessment can be useful when the wall's make-up is unknown. Drying conditions, ventilation and compatibility between primer and paint matter as much as the formulation of the finish.
Practical application at Humix Paint
The documentation for Pared Seca states that it lets water vapour escape from the wall instead of trapping it. MATE5000 AntiHumedad is also described as breathable and anti-condensation, for interior use only. Both are finishing paints, not systems to stop water rising from the ground. For rising damp and water ingress, work on the source and drying must come before painting.
Key idea
The useful question isn't just “is it breathable?” but “is it compatible with this surface and the way it gets wet and dries?”. That difference avoids confusing a property of the coating with a diagnosis of the damp.
Technical and scientific sources
- Whole Building Design Guide, Moisture Management
- Historic England, Masonry Buildings (2025)
- National Park Service, Common Problems with Brick Masonry
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.
