In the hands of the H.G Matthews master brickmakers there is a kind of alchemy at work.
The humble clay that is harvested from beneath its 650-acre Buckinghamshire premises is transformed into a finished product with unique hues, colours and surface textures. The firm has called the verdant Chesham countryside its home since 1923 and it is here that Jim Matthews – grandson of the eponymous founder Henry George – is continuing a commitment to timeless craftsmanship, combined with a commendable dedication to sustainability.
Adopting more environmentally conscious building practices can take many forms and one way to achieve it can be by returning to some of the trusted methods of our forebears. The outcome is an industry that is more instinctively in harmony with the world around it, and which champions natural and locally sourced materials. One such example is the revival of wood-fired brick kilns, a process which is now unique to H.G Matthews.
“Wood is the only fuel that produces a genuine random glazed pattern on the bricks, and a beautiful patination to a building,” explains Jim Matthews. “A part of our business is supplying brick to heritage projects, and we’re often asked to match Tudor or Georgian era bricks that were themselves manufactured with what has become the lost art of wood firing. The only way we could previously do that was to artificially glaze the bricks. That does the job but has never been completely satisfactory so we decided to go back to a wood fired kiln – and the results are quite striking.”
Given that the technique had died out across the whole of Europe, taking the decision was the easy part – putting it into practice would prove more challenging. “The only people who still worked with wood-fired kilns was the Colonial Williamsburg living-history museum in Virgina, which includes a brickworks on its grounds. We brought some of their experts over to the UK, built a kiln, and the results were truly amazing. In fact, we immediately knew it’s something that was commercially viable.”
“There’s no doubt it’s a high-end product but if you are looking to sensitively conserve and restore an old building that already exhibits wood-fired bricks it really is the only way to do it authentically. It’s not just in the heritage market, either, because we’ve also supplied them for custom new builds, and the finish is superb.”
Carbon cutting It’s not just in wood firing that H. G Matthews is maintaining many of the traditional techniques because the fundamentals of handmade brickmaking have changed little. What the company has introduced is new technologies that are reducing its carbon footprint at every stage.
H.G Matthews is fortunate that it is in command of a significant acreage from which to source its clay, but the site also contains large deposits of loam. In a process known as pugging this material is added to clay at the ratio of 25% of the mix. This very fine sand acts as
a stabiliser, preventing cracking and increasing a brick’s strength. Each brick also contains at least a pint of water, which is collected as rainwater from the brickyards’ roof.
The wet clay is then fed via a conveyor through three sets of rollers, where any flint or stone content is finely crushed. This prevents those stones from expanding when in the kiln and blowing the bricks. The clay is then hand thrown into sanded moulds by the company’s skilled team of brickmakers. It’s a physically demanding process but the reward is a timeless surface texture and a product that will last centuries.
The next stage is the drying room. Historically, brick making was a seasonal activity with good weather required for the outdoor drying of the bricks, which could take more than two weeks. Today, dedicated drying rooms do the job in just a few days. Introduce too much heat too quickly and the bricks will crack, which is why the temperature is slowly taken up to 50˚C. Ultimately, in each room, 16,000 bricks at a time, will have over 8,000 litres of water removed from them over a four-day period, rendering them much harder in the process, and ready for stacking in a kiln.
The drying rooms’ heat exchangers were previously powered by Diesel with H.G Matthews burning 30,000 litres every month just for this process alone. Under pressure from the volatile price of fossil fuels, and with the introduction of the Renewable Heat Incentive, the switch to cheaper and more environmentally friendly biomass boilers became commercially viable.
The eleven biomass boilers on site are fed with approximately 2,000 tonnes of soft wood chip a year whilst the aforementioned wood fired kiln makes use of denser hardwood logs that will deliver a slower and longer burn. Moreover, not content with what is already a very environmentally conscious operation, H.G Matthews is currently working on a prototype carbon capture unit that could remove up to 60% of the CO2 emissions from the process.
The kilns are where the real magic happens, yielding a finish that is unique to H.G Matthews, and the type of clay found in the vicinity. The ‘Scotch kiln’ design goes back to Roman times and, in a process called ‘setting’, it takes up to a week for two people to fill these 
three feet thick oil-fuelled boxes with 60,000 ‘green’ bricks. This is an oxygen rich burn where the 1,000 degrees of temperature can never be entirely evenly distributed and the result is a vivid range of colours, from purples to browns through to reds and oranges, depending on the brick’s position in the kiln.
Natural answer
For Jim, it is the unpredictably of working with this natural material where the real passion lies: “The decline of the local handmade brickworks around the country has been a disaster for the building industry,” he concludes. “We produce a particular type and colour of brick here because of the clay in this area, and you wouldn’t be able to replicate it anywhere else. That’s why, depending on the region, you have such distinct vernaculars amongst old buildings. Thanks to the volume manufacturers everything has been homogenised to a uniform and consistent aesthetic. What we want to do is champion what clay will do naturally. At the same time, we’re making sure that we’re treading with as light a carbon footprint as possible in all of our production processes.”
For further information on H.G Matthews click here
