Gjenge Makers is a pioneering Kenyan startup dedicated to addressing plastic waste and providing sustainable building solutions. Founded by Nzambi Matee, a materials engineer, Gjenge Makers transforms discarded plastic into durable, eco-friendly construction materials. This innovative approach not only tackles the growing problem of plastic waste but also offers a sustainable alternative to traditional building materials.

The Inspiration and Founding
Nzambi Matee founded Gjenge Makers in 2017. She was driven by a passion for environmental sustainability and a desire to address plastic waste in Kenya. Frustrated by the lack of viable waste management solutions, Matee leveraged her engineering background to create a practical solution. Her goal was to convert plastic waste, often seen as a nuisance, into something valuable and beneficial for communities.
The Process
Gjenge Makers employs a sophisticated yet practical process to transform plastic waste into durable sustainable building materials. This process involves several key steps, each using specific technologies and techniques to ensure the final product is strong, versatile, and environmentally friendly.
Collection and Sorting
The process begins with collecting plastic waste from households, businesses, and recycling centers. Gjenge Makers collaborates with waste management companies and local communities to gather a diverse range of plastic types, including high-density polyethylene (HDPE), low-density polyethylene (LDPE), and polypropylene (PP). Once collected, workers sort the plastic waste based on type, color, and quality. Sorting is crucial because different plastics have different melting points and properties, which affect the quality and consistency of the final product. Manual sorting is often complemented by automated systems that use optical sensors to identify and separate plastics more efficiently.
Cleaning and Shredding
After sorting, workers thoroughly clean the plastic waste to remove contaminants such as dirt, labels, and other residues. This step ensures that the final product is free from impurities that could weaken the materials or affect its aesthetic quality for sustainable building construction. Workers then feed the cleaned plastic into a shredder, which cuts it into small, uniform pieces. Shredding increases the surface area of the plastic, making it easier to melt and mix with other materials. This step is essential for creating a homogenous mixture that ensures the strength and durability of the final product.
Mixing and Heating
The shredded plastic pieces are mixed with sand in precise proportions. Sand is chosen for its availability, affordability, and excellent binding properties. Workers carefully control the ratio of plastic to sand to balance flexibility and strength in the final product. They then heat the plastic-sand mixture to the appropriate temperature to melt the plastic. This heating process takes place in a specialized machine known as an extruder or a thermal mixer. The extruder applies consistent heat and pressure to the mixture, ensuring that the plastic melts uniformly and thoroughly coats the sand particles. This process creates a composite material with enhanced mechanical properties.
Molding and Compression
Once the plastic-sand mixture is adequately melted and mixed, workers transfer it to molds that shape the material into bricks or paving blocks. The molds produce uniform shapes and sizes, ensuring that the final products meet specific standards for construction use. Workers then subject the filled molds to high pressure using a hydraulic press. This compression step is critical as it removes air pockets, compacts the material, and increases its density. The high pressure also enhances the bonding between the plastic and sand particles, resulting in a product that is significantly stronger than conventional concrete bricks.
Cooling and Curing
After compression, workers allow the molded bricks or blocks to cool and cure. Cooling solidifies the plastic, locking the sand particles in place and forming a rigid structure. The curing process, which can take several hours, further strengthens the material by allowing any residual stresses to dissipate. During curing, workers keep the bricks in controlled conditions to prevent rapid temperature changes that could cause cracking or warping. Once fully cured, the bricks are ready for quality inspection and testing.
Quality Control and Testing
Gjenge Makers conducts rigorous quality control tests to ensure that each batch of bricks meets the required standards for strength, durability, and safety. These tests include compression testing, flexural strength testing, water absorption testing, and thermal testing. By passing these tests, the bricks gain certification for use in construction projects, guaranteeing their reliability and longevity.
Impact and Benefits
Environmental Impact
Gjenge Makers addresses the critical issue of plastic pollution by diverting plastic waste from landfills and the environment. By transforming this waste into valuable building materials, the company helps reduce the environmental burden and promotes a circular economy.
Economic Opportunities
The startup creates employment opportunities for local communities, particularly for waste collectors and workers involved in the manufacturing process. By supporting the local economy, Gjenge Makers contributes to community development and poverty alleviation.
Affordable Housing
With the high cost of building materials being a significant barrier to affordable housing in Kenya, Gjenge Makers provides a cost-effective alternative. Their bricks are not only cheaper than traditional materials but also offer superior strength and durability, making housing more accessible to low-income families.
Recognition and Future Goals
Gjenge Makers has received widespread recognition for its innovative approach and significant impact. In 2020, Nzambi Matee won the Young Champions of the Earth prize from the United Nations Environment Programme (UNEP), highlighting her contributions to sustainability and innovation.
Looking ahead, Gjenge Makers aims to scale its operations and expand its reach within Kenya and beyond. The company plans to increase production capacity, develop new products, and explore partnerships with governmental and non-governmental organizations to promote sustainable construction practices.
Conclusion
Gjenge Makers exemplifies the power of innovation and entrepreneurship in addressing environmental challenges. By transforming plastic waste into durable building materials, the startup not only reduces pollution but also provides affordable housing solutions and economic opportunities for local communities. Gjenge Makers stands as a testament to the potential of upcycling and sustainable practices in creating a better, more sustainable future.