In a modest workshop in Nairobi filled with metal pipes, gears, and improvised machinery, Nzambi Matee has built one of Africa’s most practical responses to plastic waste.
The 29-year-old Kenyan engineer, inventor, and entrepreneur is the founder of Gjenge Makers, a company that converts discarded plastic into durable paving bricks that are stronger than conventional concrete. What began as a small experiment has grown into a working production model that is steadily attracting attention across the construction and environmental sectors.
Each day, Gjenge Makers produces around 1,500 plastic pavers, supplying schools, homeowners, and developers looking for materials that are both affordable and long-lasting. The bricks are made by combining recycled plastics such as high-density polyethene, low-density polyethene, and polypropylene with sand, then heating and compressing the mixture into solid blocks.
The result is a product that is not only up to seven times stronger than concrete but also lighter and more flexible, reducing breakage and extending its lifespan. The pavers have a melting point of over 350 degrees Celsius and are fully certified by the Kenyan Bureau of Standards, giving them credibility in a market that is often cautious about alternative building materials.
The journey of Nzambi Matee into this space was shaped by both technical training and lived experience. With a background in material science and engineering, and having worked in Kenya’s oil industry, she became increasingly aware of the scale of plastic waste in Nairobi. The sight of plastic bags and bottles scattered across streets pushed her to explore how the material could be repurposed rather than discarded.
“Plastic is a material that is misused and misunderstood. The potential is enormous, but its afterlife can be disastrous,” Nzambi Matee said. “It is absurd that we still have this problem of providing decent shelter, a basic human need.”
The early stages of the project were far from straightforward. In 2017, Matee left her job as a data analyst and set up a small lab in her mother’s backyard, where she began experimenting with different combinations of plastic and sand. The process involved repeated trial and error to determine which types of plastic bonded effectively and how to achieve the right ratios for strength and durability.
Her work drew mixed reactions at the time. Neighbours complained about the noise from her machines, forcing her to negotiate for time to refine her product. That period of persistence proved critical in developing the prototype machine that now underpins Gjenge Makers’ production process.
Further refinement came through exposure to global research environments. After securing a scholarship to attend a social entrepreneurship programme in the United States, Nzambi Matee used facilities at the University of Colorado Boulder to test and improve her material compositions. This helped standardise the production process and strengthen the quality of the final product.
Today, the company operates at the intersection of environmental management and construction, giving a second life to plastic waste that would otherwise end up in landfills or pollute urban spaces. The model also supports local recycling networks, creating demand for waste collection and contributing to income generation at the community level.
Globally, the scale of plastic consumption remains high, with one million plastic bottles purchased every minute and up to five trillion single-use plastic bags used annually. Within this context, Matee’s work reflects a broader shift toward practical, locally driven solutions that address environmental challenges while meeting everyday needs.
The efforts of Nzambi Matee were recognised in 2020 when she was named a United Nations Young Champion of the Earth, an award that supports emerging environmental leaders with funding and mentorship. The recognition placed her among a growing group of innovators using technology and design to rethink how materials are used and reused.
As demand for affordable construction materials continues to rise across African cities, innovations like what Nzambi Matee is doing through her company Gjenge Makers are beginning to shape alternative pathways for building. Matee’s work demonstrates that solutions to complex challenges can emerge from small, locally grounded experiments, provided they are backed by technical rigour and persistence.