Construction waste is being repurposed into eco-friendly building blocks for low-cost Reconstruction and Development Programme (RDP) housing through a Department of Science, Technology and Innovation (DSTI) initiative.

Last month, research institute the Council for Scientific and Industrial Research (CSIR), in partnership with nonprofit organisation Use-It Waste Beneficiation and building solutions company Key Bricks, unveiled a prototype house built with the blocks.

The site visit provided “behind-the-scenes” insights into Key Bricks’ operations, material mix ratios, structure design and the equipment used to produce the interlocking block.

Use-It and Key Bricks shared their journey on the steps they took in their operations and their close collaboration with the CSIR to test and refine product ideas and adopt circular economy principles.

The green block comprises 70% recycled waste content, including crushed waste glass and construction and demolition waste, making the block itself 100% recyclable.

Additionally, the design of the interlocking block enables “easy” building construction and, if needed, the structure can be deconstructed and reused at another location.

The block is designed to interlock like LEGO blocks, requiring no cement between layers. Each block features internal hollows which, when stacked, create channels for installation of electrical and water pipes, reducing the need to cut grooves and ensuring that the blocks remain intact.

The DSTI Socioeconomic Innovation Partnerships deputy director-general Dr Mmboneni Muofhe and CSIR Hosted Programmes executive manager Bongani Memela presided over the ribbon-cutting ceremony for the newly built demonstration house. CSIR project manager Aubrey Muswema, Use-it MD Belinda Putterill and Key Bricks CEO Matt Oliver also attended.

The CSIR noted that the blocks resulted from the need to find markets for waste glass and building rubble in KwaZulu-Natal (KZN).

“It’s not viable to transport waste glass from KZN to Gauteng for recycling, the margins on this are just too slim, resulting in a lot of this waste remaining uncollected and impacting the environment,” said Putterill. “We need to find ways to use glass locally in KZN.”

Moreover, cities, towns and villages across the country are also plagued with the illegal dumping of building rubble in open spaces. As these blocks use construction and demolition waste, they can help to reduce dumping, in addition to reducing the need for conventional virgin materials.

Muswema explained that building with the innovative block is cost-effective, saves construction time and requires minimal labour and building experience.

Local businesses and value chains can also benefit from the potential to generate additional revenue streams.

Further, the blocks also have the potential to accelerate social relief efforts by addressing the country’s housing backlog.