UCT MSc student builds sustainable home from soil and recycled waste

Matimba Mabonda standing in front of the house he built with soil and recycled waste. A master’s student at theUniversity of Cape Townhas completed a three-bedroom house constructed largely from soil and recycled waste, positioning the project as a practical response to South Africa’s housing and waste challenges. Matimba Mabonda, who holds a degree in chemical engineering and is currently completing his MSc, led the pilot build in Ennerdale, Johannesburg.

The house was constructed using natural soil combined with plastic and glass waste, resulting in a fully functional home designed to deliver comfort and energy efficiency while reducing environmental impact. South Africa generates an estimated 122 million tonnes of solid waste each year. Mabonda’s project aims to demonstrate how some of that waste can be repurposed into durable housing materials.

After graduating, Mabonda partnered with his father, Ben Mabonda, a contractor with decades of experience and hundreds of completed builds, to turn the concept into reality. “Sustainable building has always been an area of interest for me, and after graduating with my degree it made sense to venture into how to make it work and that’s what I did,” he said. Mabonda’s drive is rooted in his upbringing.

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He grew up in a shack in Grasmere, Ennerdale, where he witnessed the effects of South Africa’s housing shortage first-hand. “I always wanted to improve things for my family. We also have a massive housing crisis in South Africa.

So, I thought if I could contribute to solving this crisis while keeping sustainability top of mind and changing circumstances for my family and others out there, that would be great and make me so happy,” he said. The initial plan was to use “lolabricks” — blocks made from plastic and industrial waste without cement or water. However, the high cost of industrial machinery required for large-scale production proved a major hurdle.

Mabonda then shifted focus to earth-build technologies, which use raw soil as a primary construction material. Preparing soil for construction requires testing and analysis to determine the correct composition for structural integrity. According to Mabonda, soil composition varies by location and the size of the structure, meaning builders must blend different soil types to achieve optimal results.

For the pilot house, the team incorporated plastic waste into the soil mix while maintaining the structure’s strength and stability throughout construction. “More than 90% of our walls were made from earth materials, as well as plastic waste. Our house is comfortable. It’s warm in winter and cool in summer – making it the ultimate living space and there’s no need for expensive air conditioners either,” he said.

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