All He Surveys: Grant Crossley on Bungaroosh

In his final column of the series, Grant Crossley dishes the dirt, quite literally, on Brighton’s notorious building material, Bungaroosh

“I beg your pardon, Bunga-who?” A common reaction. Bungaroosh is a composite building material made from a mixture of ingredients. Imagine this being a cake mix, perhaps, in this case a Rock Cake – excuse the pun. The recipe generally contains broken pieces of brick and flint, sometimes chalk (known as clunch), timber off-cuts and any other types of solid rubble available at the time, all thrown into one concoction; temporarily braced by timber planks and bound together with lime mortar.

This method of construction was rife in Brighton during the 19th century and often used to build supporting walls; at the time it was cheaper than brick.

More often than not, bungaroosh walls make up the rear and party walls of traditional Brighton town houses, whilst the Regency-style front façade is more often masonry; but, it’s not uncommon to find bungaroosh hidden behind. On the outside, the walls were finished with a lime-based render and occasionally lined-out to imitate stone; whilst a spread of plaster, again lime-based, was applied to the internal surface.

Then, bungaroosh offered a durable and cost-effective way of building; now, it delivers a range of technical hitches.

Too wet, too dry
Bungaroosh’s resistance to water is not fantastic. The mixture is very porous; too wet and some ingredients can dissolve, causing the solid materials to move around. Whilst on the other hand, if it gets too dry, the wall can crumble and even collapse.

Breeding ground for decay
Theoretically, a bungaroosh wall’s best state is a little damp. But when timber is added the permeability of the wall can create the perfect breeding ground for timber decay.

Hard as nails
Once set, bungaroosh is rock-hard. Drilling into the material is often difficult. Bits of wood used to be set into the wall as it was erected to create fixing points. These days, timber grounds are concealed, often rotten and set-out to the building’s original layout.

The need to breathe
Lime-based render lets a bungaroosh wall breathe, allowing inherent moisture to evaporate. Slapping a modern hard-cement-based render onto the surface can seal the wall and trap moisture, which overtime can cause serious damp problems and potentially destroy its structural integrity.

DIY repairs
Repairing a bungaroosh wall is not simple, and definitely not for an amateur. Don’t ignore any problems; consult a local Chartered Surveyor or Structural Engineer to inspect any defects and report upon the best method of repair.

Risky business
So, staying true to its name, the haphazard construction technique was ‘bunged’ full of a mix of readily available ingredients, and every ingredient can cause problems. As a result this cake is not for trifling with. So just remember, you won’t be able to have your cake and eat it, if you chose to ignore its pitfalls!