When considering the carbon footprint of construction materials, we often focus on concrete and steel—the two largest emitters. However, another commonly used product also merits attention. Brick is a ubiquitous building module produced in significant quantities worldwide. A recent estimate of the annual global production of bricks by California-based Global Industry Analysts is approximately 1.5 trillion units (not including concrete bricks); another study by the École Polytechnique Fédérale de Lausanne in Switzerland approximates the output at 2.2 billion metric tons. According to EPFL researchers Karen Scrivener and Hisham Hafez, worldwide fired clay-brick production contributes 0.48 kg CO2eq per kg, or 1.1 Gt CO2eq, total emissions, each year. (Total global energy-related CO2 emissions were 36.8 Gt in 2022.)
As seen in other material industries, brick has become a focus for experimentation. Several manufacturers have developed building modules that replace fired clay with substitute materials requiring less embodied energy. A common surrogate is plastic that has been repurposed from waste streams and is either incorporated alone or in combination with other materials. Many of the entrepreneurs pursuing such an inventive approach are based in South Asia and Africa—territories with rich histories of brickmaking but which, due to highly fragmented and unregulated industries, contribute significant quantities of pollution. For example, the U.S. EPA estimates that brick kilns in India are responsible for two-thirds of the nation’s industrial black-carbon emissions. These same regions also struggle with the burgeoning presence of polymer waste, hence the practical solution to divert plastic debris into creating alternative bricks.
According to media platform The Better India, India is the second-largest brick maker globally, and its brickmaking industry utilizes significant quantities of coal for processing. Concerned about the resulting pollution, Gujarat-based inventor Manish Kothari devised a new type of brick composed of waste plastic and foundry dust (sand used in metal casting foundries). Kothari’s company Rhino Machines produces the so-called Rhino Brick from 100% repurposed materials without water. The bricks are 25% lighter and 2.5 times more robust than the standard clay variety. Due to popular demand for its product, the company plans to establish new manufacturing plants at different foundry locations to expedite brick production and mitigate transportation energy.
Kolkata-based entrepreneur Abhishek Banerjee had a similar idea. A high school field trip to a West Bengal brick kiln left a lasting impression on him. Banerjee was struck by the unsafe working conditions he witnessed there and was appalled to learn about the heavy environmental impact of the coal-fired process at such kilns. While pursuing a construction engineering degree at Jadavpur University, Banerjee had the notion of using waste plastic—25,000 metric tons of which is reportedly produced daily in India—to make new bricks. The result is PlastiQube, interlocking construction modules made entirely from discarded plastic. Produced by Qube—the company Banerjee founded with his classmates Agnimitra Sengupta, Ankan Podder, and Utsav Bhattacharyya—the bricks are half the weight of traditional bricks and require no mortar due to their interlinking design. The modules are “plastic agnostic,” meaning that any plastic may be used—thus eliminating sorting time and effort—and require only 30% of the embodied energy of standard bricks. For his invention, Banerjee was recognized as regional finalist for the United Nations Young Champion of the Earth award and (along with his Qube cofounders) a Forbes “30 Under 30” Social Entrepreneur for Asia.
As in India, many African countries struggle with polluting brick industries and plastic refuse. Nairobi, Kenya-based Gjenge Makers manufactures paving bricks, tiles, and even utility hole covers from discarded polymers. Inventor and activist Nzambi Matee left a job in the petroleum industry, the source of oil-based plastics, with the idea to course-correct a growing problem. “Here in Nairobi, we generate about 500 metric tons of plastic waste every single day, and only a fraction of that is recycled,” Matee says in a United Nations video (she was also recognized as a Young Champion of the Earth). Gjenge Makers receives much of its scrap for free from industries eager to offload their plastic waste. The manufacturer then shreds the material and mixes it with sand, cooks it at high heat, and pours it into various molds for different products. The resulting pavers are reportedly half the weight and between two and seven times stronger than standard concrete versions.
Ghana-based manufacturer Nelplast Eco developed its line of recycled plastic bricks and pavers to alleviate the country’s housing shortage as well as its pollution problem. With a deficit of 1.8 million homes, overcrowding in informal settlements consisting of makeshift shelters is a growing crisis in Ghana. In Ashaiman, where Nelplast Eco is based, garbage collection services are also inadequate. Half of the solid waste—nearly a quarter of which is plastic—goes uncollected there. This refuse clogs city drains and waterways, exacerbating flooding. (Nelplast Eco founder Nelson Boateng was inspired to launch his company after nearly perishing in a 2010 flood.) Nelplast Eco purchases the plastic feedstock for its building modules from informal waste pickers, most of whom are women, providing them with a consistent income. Like PlastiQube, the manufacturer’s bricks have an interlocking design, thus requiring no mortar. According to the company’s submission to the MIT Climate Adaptation & Low-Carbon Housing Challenge, the residential structures built with its bricks are not only less carbon-intensive but also 40% less expensive than the average Ghanaian home.
As plastic waste becomes a more viable ingredient for building, the material faces increasing scrutiny. For example, a method to incorporate discarded plastic in the asphalt mix of new road construction in India has received mixed responses. Given the significant extent of new roadways under construction, offsetting a portion of the raw materials with waste plastic can deliver substantial environmental benefits. According to one estimate, every kilometer of single-lane road offsets one metric ton of plastic waste, which also extends the road’s life. However, concerns about the potential dispersion of microplastics and the inclusion of environmentally harmful polymer additives necessitate more study. That said, this general strategy’s many benefits—reducing waste, offsetting virgin construction materials, decreasing emissions, and providing sustainable employment—demand further attention. Perhaps most significantly, we should all take inspiration from the creative innovation being led by Global South entrepreneurs with a planetary perspective. As Nzambi Matee argues, “Plastic waste is not just a Kenya problem, but it’s a worldwide problem.”
The views and conclusions from this author are not necessarily those of ARCHITECT magazine or of The American Institute of Architects.
Read more: The latest from columnist Blaine Brownell, FAIA, includes looks at a homewares line made from recycled footwear, immersive art exhibitions, and material technologies that improve air quality.