This innovative building material has been developed with the goal of, among other things, minimizing brick waste while supporting green building design.
by Professor Gabriela Medero, Co-founder of Kenoteq and Professor of Geotechnical and Geo-environmental Engineering at Heriot-Watt University
The Importance of Minimizing Brick Waste
Anyone who has been lucky enough to visit Antoni Gaudi’s Casa Mila in Barcelona knows that a love of conscientious design and construction practices are not mutually exclusive.
One of Gaudi’s many design innovations is called trencadís, the use of waste ceramic pieces to create elaborate and stunning mosaics. He understood that just because something had been used before, it didn’t mean it couldn’t be used very effectively again.
Waste is a major problem for the construction industry. In the UK alone, more than a third of waste comes from construction and demolition yet materials continue to be extracted to meet the demand for over 2.6 billion bricks a year. Globally, the construction industry contributes 39% of all CO2 emissions1. It was this troubling trend that ultimately led to the creation of the K-Briq.
Working with a team of engineers, architects, chemists, designers, and geologists, we questioned whether some of this waste could be productively re-used, and this proved to be the catalyst for change.
Simply re-using old bricks is not the answer. Once removed from old structures they need to be cleaned of mortar with hammers and chisels. Reclaimed bricks are used to help renovate historic buildings or for other specialised projects but for mass construction, the process is too costly.
It requires an incredible amount of energy to produce a single brick. In clay brick firing, fossil fuels are burned so kilns can reach temperatures up to 1,300 degrees Celsius. In turn, the process generates both carbon monoxide and sulphur oxides, and the fine dust created during production adds a further layer of pollution to our air.
Concrete bricks are equally damaging, requiring the use of cement, one of the largest contributors of carbon emissions.
Ten years of research and development then followed to examine this challenge in detail, working out of the laboratories of Heriot-Watt University and onsite at a local waste handling facility.
Perhaps our biggest challenge was to develop a material that could offer the same or even better performance than traditional fired clay or concrete bricks. We set out to produce a strong brick that could respond well in extreme weather, such as freeze-thaw cycles, is fire resistant and has excellent insulation properties. We also examined the Building Standard requirements – all without either firing or adding cement.
We started at the end of the lifecycle of construction, examining the landfill created by the industry and exploring how these precious materials could be given a new lease of life.
In 2011, development of the first K-Briqs began. Working with the waste handling facility, concrete, rubble, old bricks, and plasterboard were separated, washed, and crushed down into manageable fractions. These materials were used as feedstock to produce the K-Briq.
Thousands of bricks were tested to fully understand their properties, performance and durability in detail.
The result of all that research and development is a premium-quality brick, the K-Briq, made from over 90% construction and demolition waste. The manufacturing process requires less than a tenth of the energy used during the creation of clay fired bricks and produces only a tenth of the CO2 emissions.
The brick has a high thermal mass, which retains heat in the winter and keeps buildings cool in the warmer summer months, so heat and air conditioning costs and energy requirements are kept to a minimum.
The speed at which the product can be produced is also impressive. Within 24 hours of an order of K-Briqs being placed, they can be manufactured, packaged and ready for delivery.
Completing the circular economy pathway, the bricks are manufactured onsite at a waste handling facility, so transport miles are reduced, and the amount of CO2 used in production is further limited. Trucks can also collect K-Briqs when they drop off the waste material, cutting the number of journeys made.
The K-Briq can also be produced in a range of colours which makes it more attractive for interior designers, architects and builders looking to offer something different without harming the environment and while working to regional planning requirements.
Together with other innovative building materials, such as the use of reclaimed wood, bamboo as a wood alternative, bio-glass, and jute-fibres for insulation, the K-Briq can help the design and construction industries to meet their net zero targets.
At Kenoteq, we are dreaming big. Last year, we were awarded £1 million in funding by Zero Waste Scotland to commercialise production to up to three million bricks per year. Large volumes of bricks will be achieved by the end of 2022. This may be a tiny portion of the market (globally, 1,500 billion bricks are produced every year and laid end-to-end, they would stretch to the moon and back 390 times), but it is a starting point.
Currently, all brick production takes place near clay extraction, as opposed to areas where the bricks are needed most, such as in the South-East of England. We plan to produce K-Briqs as close to the point of construction as possible, in areas of demand for bricks and next to waste recycling centres across the country. In the UK, the industry currently imports 500 million bricks per year to meet national demand. This needs to change urgently.
But creating a revolution in any industry isn’t easy. More support from governments is essential, both globally and here in the UK. Too often, legislation lags far behind innovation, so construction companies need to be better incentivised to adopt sustainable practices and materials.
In design, legislation needs to make the integration of environmentally sustainable practices and materials as fundamental as fire prevention measures. Until they are enshrined in law, green building practices remain at the whim of the developer or designer. Fortunately, a growing number of developers, architects and interior designers are embracing sustainable alternatives in an effort to curb climate change.
For our part, projects are in progress and there are several companies and organisations planning to use our bricks, with a number of large projects in the pipeline. Of course, developing greener bricks is just one way to build towards more sustainable construction and design industries but, as everybody knows, you can’t build anything without laying the first brick.
The K-Briq is just one part of the puzzle but I’d like to think that Gaudi would approve.
1 Report from the World Green Building Council: The building and construction sector can reach net zero carbon emissions by 2050