Why old houses need to breathe
If your home was built before about 1919, it almost certainly works in a completely different way to a modern house — and getting that wrong is the single most common cause of damp misery in older properties.
No cavity, no plastic, no problem — by design
Modern houses keep water out: a cavity between two leaves of wall, a physical damp-proof course, and impermeable materials form a barrier. Older buildings do the opposite. They're typically built of solid stone or brick laid in lime mortar, finished with lime plaster and breathable paint. They manage moisture rather than block it — absorbing it when it's wet, then letting it evaporate back out when conditions allow. The whole wall is designed to breathe.
How modern "fixes" cause the damage
Problems start when someone treats an old building like a new one. The usual culprits:
- Cement render and pointing — hard, brittle and largely waterproof. It traps moisture behind it, forces it to escape through the stone instead, and accelerates decay.
- Gypsum plaster and plastic (vinyl) paints — seal the inside face, so moisture that should evaporate indoors is trapped in the wall.
- Injected chemical damp-proof courses and tanking — sold as the cure for "rising damp", they interfere with how a solid wall handles ground moisture and rarely address the real cause.
The result is damp that gets worse, salts brought to the surface, blown plaster, rotting skirtings and timber — and often a building whose historic fabric has been quietly wrecked in the process.
What actually works
The right approach is almost always to let the building breathe again: breathable lime-based repairs, removing impermeable coatings, sorting out maintenance (gutters, pointing, ground levels) and improving ventilation. None of it is exotic — but it has to start with a correct diagnosis of why the wall is wet in the first place.
That's exactly where an independent assessment earns its keep. We don't sell render, plaster, injection or tanking — so there's no incentive to recommend the very things that damage these buildings. We diagnose how your building is meant to behave, what's stopping it, and what will genuinely help.