Living With & Understanding Bungaroosh Q&A with Neil England of Heritage Building Advisors (HBA)

Neil kindly agreed to talk about bungaroosh at Kind last month as part of our ongoing monthly discovery events. We have created this Q&A for those unable to attend and to help raise awareness of this historic building material. We feel that it is a perfect example of low-impact, local vernacular construction.

Let us know what you think!

Q: What prompted you (Neil) to create a downloadable pamphlet on Bungaroosh to host a talk about it?

Bungaroosh is a historic shutter formed wall system, popular in the pre and post Regency period, that has been much maligned and misunderstood in recent decades. The negative press has gotten so bad that insuring a Bungaroosh building has often become challenging. The pamphlet and talk.  People are only starting to re-learn and understand its unique qualities again. The pamphlet and talk were designed to help people understand the basics of materials and how to work with it. A well-maintained bungaroosh wall can provide residents with a healthy internal living space and ensure the long-term health of a building.

Q: What is Bungaroosh made up of and how do you spell it?

Bungaroosh was a series of mixed interlocking elements, principally lime, busted gravel, coarse sands with nodular field (and some) beach flints and brick fragments or snaps as part coursing, with other to-hand rubble added. The combination forms rough mortar or a large lump form of lime concrete.  A unique characteristic is that the elements used, like flint nodes and chippings, were predominantly angular. This meant that they interlocked easily, and the material quickly bound together.

For years, I spelt it with the "U", Bungaroush, but the double "O" seems to be prevalent these days. Many have speculated, but the name's origins are lost in the fullness of time, so I could not tell you.

Q: Why was this material so popular in and around the Brighton region?

It was popular because it was cheap and effective! Bear in mind, structure cost was the biggest deciding factor when building in the Regency era and probably still is today. Compared to bricks, which were taxed, Bungaroosh was an inexpensive alternative that made use of the unwanted elements like the field flints, broken and half-baked waste bricks. Additionally, the elements needed to create bungaroosh were close by and prevalent in the fields and South Downs around Sussex. Labour was also cheap, that meant that the labour needed to break up flints to create the small angular chippings for the mix, was inexpensive.

As said. Not only was it cheap and easily available, Bungaroosh was also an easy material to work with. You didn't need to be a brain surgeon. You just need to understand the repetitive nature of it.

Q: In your opinion, what are the benefits of the presence of Bungaroush in your property?

As long as you do not abuse it, Bungaroosh's unique qualities can look after the occupants' health and the longevity of the building. It has a proven track record. As a material, it is probably 70% of all the listed buildings in the country down below London. These buildings have been standing for well over two hundred years. Bungaroosh is a multi-solution material providing load-bearing, moisture-regulating, and thermal benefits.

Structurally, it has no master, is appropriately built in the day with the correct amount of limes, and is the perfect material to build up to four or five floors. The fact is that it is a supporting mechanism, a product that keeps out the damp. It works exceptionally well. It's highly absorbent, but it gives, it absorbs only to about a depth of 25 to 30 mil. That's the max I've ever found. And gives it back out quite quickly, proving it can do so. Where it fails is when they put cement skins over it.

Moisture. It's very good with moisture. Oh yes, it's so good that it can carry on absorbing moisture. I mean, forget the idea of needing to damp-proof it. Bungaroosh will take on the water and absorb it to a point where it becomes a saturated mass but will not collapse. It holds the moisture until the humidity levels decline, allowing it to release it. Bungaroosh helps regulate and maintain a healthy internal environment by acting as a moisture sink, balancing seasonal extremes.

Bungaroosh will act similarly to thermally regulate the internal temperature by providing thermal mass. Because it is full of air holes at a cellular level, they do not usually have a solid core. So, their ability to reflect heat allows them to retain still air, acting as a heat reflector. As a bonus is also an excellent sound reducer.

So unlike modern materials bungaroosh will constantly react with the environment.

Q: Bungaroosh has received a lot of negative press in recent decades; what impact has it had on properties built with it?

Securing insurance for listed buildings with bungaroosh can be a challenge. Unfortunately, due to the misperceptions it has garnered, many believe that bungaroosh is prone to collapse. What's often overlooked is that these very buildings depend on bungaroosh as their sturdy foundation. The instances of bungaroosh failures are primarily a result of poor maintenance and misguided repairs using non-breathable materials such as cement and plasticised paints. 

The negative press was started by people who didn't understand it, and to a gradual extent, they still don't. They can't get their head around it because it's not made of one brick on top of another! If you don't understand something, you ridicule it! For example, until we recently changed it, the bungaroosh post on Wikipedia was scathing, joking that a well-aimed fire hose would destroy most of Brighton. I felt passionate about it, especially since some clients have said they needed to remove the bungaroosh walls. This shocked me completely and has moved me to where we are today.

We've successfully removed those statements from Wikipedia and replaced them with information based on my fifty-odd years of experience in heritage building conservation and restoration.

Q: Do you think it's a material that could be used in the present?

Very interesting question.

I was asked that particular question at the talk. The gentleman said

“I've got five houses I want to build, using bungaroosh. It's a fantastic product. It looks amazing”.

I said, you can't, it is not cost effective. The field flints are no longer available in large quantities. The fields are now tilled and turned regularly and are free of flints now.

Also, you can't make it effectively, even with machinery, without the flint chippings and the bricks that we use these days, they are not half bake bricks soft, amenable, bendable. They're very hard, you have to literally take a hammer and smash them in half to make up a wall like that. So, the soft/hard interlocking nature of these walls is such that you will need somebody who's well trained in the art of doing it. Also, slow build speeds would not be tolerated I believe. 

Q: Finally, there is the present issue of insurance. We've received feedback from owners of listed buildings who have said they find it difficult to insure their buildings because of the presence of Bungaroosh.

You're much better off going for rounded flint coursing. That's quite a regular thing. There are companies set up to do that for you because beach flints are much more easily available.

The situation in play is I hope going to change now that we have changed the wording at Wikipedia and our talks and free pamphlet. HBA holds full methodology/materials specifications for repairs to maintain/restore. Any insurance company or owner/managing agents can get in touch with us for the in-depth papers to fully clarify. 

Q: What should you do next if you have any concerns or worries about the state of a Bungaroosh wall in your property?

It's crucial to consult an IHBC registered surveyor who can provide professional advice tailored to your building's needs. When it comes to bungaroosh, the rule of thumb is: if it's not broken, don't fix it. And if it is broken, avoid using modern materials for repairs. Always preserve any fallen material, add some lime to it, and have a skilled tradesman handle the restoration if possible.

Even in this era of passive housing, increased U-values and air tightness regulations that always require retrofitting with breathable, preferably lime-based materials and solutions.

A well-maintained bungaroosh wall will look after the health of the occupants and the health of the property. Don't deny its ability to look after you! Its here to stay for at least the next 2-300 years or so. Proof?  look to 1000 year old Sussex churches.