The Cement Trap: Why Brighton's Historic Homes Are Being Destroyed by Well-Meaning Repairs

# The Cement Trap: Why Brighton's Historic Homes Are Being Destroyed by Well-Meaning Repairs

Walk down any street in Brighton's conservation areas and you'll see them: Georgian townhouses with hairline cracks spider-webbing across their facades, Victorian terraces showing signs of damp creeping up from the foundations, beautiful period properties looking distinctly unwell. Most homeowners don't realise their repair attempts may be making things worse. The culprit? A well-intentioned but fundamentally flawed decision to patch bungaroosh walls with modern cement—a mistake that's becoming disturbingly common across the city.

The Bungaroosh Problem Nobody Talks About

Bungaroosh is Brighton's secret. This curious building material—a humble mix of lime, flint, pebbles, brick fragments and rubble—has held the city's Georgian and Victorian properties together for up to 300 years. When treated properly, bungaroosh walls are resilient, flexible, and remarkably durable. But bungaroosh has never been fashionable, and it's never been well understood by the modern building trade. Most general contractors see it as something to be "improved" with contemporary materials, which is precisely where the trouble begins.

The fundamental incompatibility between cement-based repairs and bungaroosh construction represents one of the most persistent and damaging mistakes in Brighton's heritage building sector. When a homeowner notices cracks forming or dampness appearing, their instinct is to call a local builder. That builder, trained in modern construction standards, reaches for cement mortar or concrete-based patches. The logic seems sound: cement is stronger, more waterproof, more durable. Except on bungaroosh, it's none of these things. It's a recipe for accelerating decay.

Why Cement Is the Enemy of Bungaroosh

The problem lies in a single, critical property: breathability. Bungaroosh walls were built to breathe. The lime mortar that binds the material together is inherently porous. Moisture can move through it freely, evaporating away rather than accumulating inside the wall structure. This is not a weakness—it's the genius of traditional building. It allows the wall to regulate its own moisture content and remain stable across centuries of Brighton's damp, salty coastal climate.

When a patch of cement damage to bungaroosh is introduced into this delicate system, something catastrophic happens. Cement is impermeable. It acts like a plastic membrane, blocking the natural flow of moisture. Moisture that would normally evaporate becomes trapped. It pools behind the cement patch, saturating the surrounding lime mortar and the bungaroosh itself. The result is rising damp, internal dampness, salt crystallisation, and accelerated decay—not just at the patch site, but spreading outward into previously sound material. The wall begins to bulge. The plaster blows. The structural integrity degrades. What started as a small crack has become a genuine problem.

The irony, of which most homeowners are unaware, is that their well-meaning repair has transformed a minor cosmetic issue into a structural concern. One contractor's decision to use cement mortar can trigger decades of moisture-related problems that ripple through the building, affecting plaster, creating damp conditions indoors, and ultimately weakening the entire facade.

A Tale of Two Repairs: What Happens When You Get It Right

Consider two terraced houses on a typical Brighton street, both built in the 1840s with bungaroosh walls. Both developed similar cracks in their external walls around 2018. Both homeowners were concerned and wanted the problem fixed quickly.

The first property's owner found a general building contractor through a local recommendation. The contractor assessed the cracks—entirely normal movement in a 180-year-old building—and advised patching with modern cement mortar. The job was completed in two days at a reasonable cost. For a few months, the wall looked repaired. By 2020, hairline cracks had reappeared. By 2022, dampness was visible on the interior plaster. The homeowner noticed soft, crumbling plaster near skirting boards, and a persistent smell of damp in the bedroom. Further investigation revealed that moisture had migrated behind the cement patch, saturating an area now five times larger than the original crack. The cost to properly remedy this damage—removing the failed cement, carefully rebuilding with lime mortar, treating the now-compromised bungaroosh, and replastering internally—ran to several thousand pounds.

The second property's owner consulted a specialist in bungaroosh repairs before deciding on a fix. Rather than patching, the specialist carefully removed the failed mortar and assessed the underlying material. The cracks, they explained, were superficial—natural settlement in a historic building. Rather than seal them with cement (which would trap moisture), the specialist applied a breathable lime render to the affected area. This allowed the wall to continue its natural moisture regulation while providing weather protection. Ten years later, that wall remains stable, crack-free, and dry. The homeowner has experienced no damp-related issues. The cost was marginally higher than the cement option, but the outcome speaks for itself.

These aren't hypothetical scenarios. They're the pattern that repeats across Brighton, week after week, as homeowners make decisions based on incomplete information.

The Right Way: Lime Render and Lime Plaster Solutions

The solution to bungaroosh damage isn't complicated—it requires returning to the principles that worked for three centuries. Breathable lime render uses traditional lime-based formulations that match the original material. These renders allow moisture to move through them freely while providing excellent weather protection. They're flexible enough to accommodate the natural movement of historic buildings without cracking. They're compatible with the underlying bungaroosh and won't trigger the cascade of dampness that cement causes.

Internally, lime plaster serves the same function. Historic properties that have been patched with modern gypsum plaster often develop damp problems for the same reason: the plaster traps moisture rather than allowing it to evaporate. Replacing gypsum with traditional lime plaster restores the wall's ability to regulate its environment naturally.

The expertise required to do this properly isn't widespread. It requires understanding not just the materials, but the principles behind them. It means resisting the temptation to "improve" on traditional methods with modern alternatives. It requires patience—lime takes longer to cure than cement, and results aren't instant. But it delivers longevity that modern materials simply cannot match.

Get in Touch

If you own a Georgian, Victorian, or Edwardian property in Brighton & Hove and are concerned about cracks, damp, or the condition of your bungaroosh walls, expert advice is available. Safe-Bricks Limited specialises in bungaroosh repairs and breathable lime render solutions specifically designed for Brighton's heritage properties. Contact them at info@safe-bricks.com or call 07459 174 692 for a consultation. Their team can assess whether your property has fallen victim to the cement trap—and more importantly, how to fix it properly.