Heritage Building Restoration and Conservation Specialists
Damp In Walls
Restore Breathability
Why Damp Persists
Most older buildings were designed to breathe. Moisture enters through rain, ground and everyday living — and then naturally evaporates away through lime mortar, plaster and timber.
The problems begin when modern materials interrupt that process. Cement, gypsum plaster, injected damp proof courses and waterproof coatings trap moisture instead of managing it.
Typical Damp Signs
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Peeling or blown plaster
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White salts on the wall
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Damp patches that never dry
- Decaying skirting boards
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Mould in corners
From £300
The Solution
At Longnor Heritage, we restore the building so it can deal with moisture properly, often solving the issue more simply and far more permanently.
What we avoid, and why
We avoid chemical injection damp-proof courses, and we avoid tanking solid walls in cementitious render.
Both are sold as permanent, and both are permanent in the most literal sense. Once a wall has been drilled and injected, or coated in waterproof render, you cannot inspect it, you cannot test whether it worked, and you cannot easily undo it. If the diagnosis was wrong, and in a solid-walled building it very often was, because these buildings have no damp proof course and were never built to need one, you have added an irreversible intervention to a problem it was never going to solve.
They also tie the building to a single system. The guarantee is worth exactly as long as the company issuing it stays in business, and the repair to a failed tanking system is another tanking system.
A breathable wall has none of those properties. It can be inspected. It can be repaired in patches. And it can be put right by anyone who understands lime, for as long as there is limestone.
Victorian Terrace
The Situation
Victorian terrace with tide marks, blown plaster, and failed skirtings. A damp-proof course had already been installed with no effect.
What We Found
The wall had been sealed with cement render and gypsum plaster. Moisture was trapped, not rising.
What We Did
Removed cement render, reinstated lime plaster, lowered ground levels. No chemical treatments.
The Result
Wall dried naturally and stabilised.
Key Point
Most “rising damp” is actually trapped moisture.
Georgian Home
The Situation
Georgian property with damp patches appearing after heavy rain on an exposed wall.
What We Found
Cement pointing was trapping moisture in the brickwork. Water could get in, but not out.
What We Did
Carefully removed cement pointing and repointed in lime mortar. No sealants used.
The Result
Wall still gets wet in bad weather but now dries properly without affecting the interior.
Key Point
Breathability matters more than waterproofing.
Edwardian House
The Situation
Edwardian house with black mould around windows, corners, and behind furniture.
What We Found
Condensation caused by poor ventilation after upgrades like draught-proofing and secondary glazing.
What We Did
Improved ventilation with trickle vents and extract fans. Advised on airflow and steady heating.
The Result
Mould stopped returning within weeks.
Key Point
Not all damp is in the walls—often it’s in the air.