A pioneering solution with a vital role to play in solving South Africa’s housing crisis
Using a blend of discarded builder’s rubble and readily available soils, Compressed Earth Blocks are stronger, greener and far cheaper than conventional materials.
When it comes to sustainable, affordable, environmentally friendly building materials, the Compressed Earth Block (CEB) certainly has winning credentials. Made from a blend comprising 30% discarded builder’s rubble and readily available clay-bearing soils, they are three-and-a-half times stronger than concrete blocks, significantly cheaper, ten times more thermally efficient and unskilled people can be trained to lay them in just one hour.
Given the high demand for new homes across South Africa, you might have expected CEBs to be in equally high demand throughout the national construction sector. “Not yet, but they should be,” comments Chris Whyte from USE-IT, a KwaZulu-Natal-based non-profit organisation that has implemented a modular system capable of manufacturing enough CEBs in a day to build two 50m2 houses.
“Earth has been used as a building material for centuries. But these days, people are wedded to the idea that new houses must be constructed from conventional building materials such as steel, concrete and wood. The problem is that there is no country anywhere in Africa that can afford enough of these conventional materials to fill the housing gap. Financially and environmentally, they are simply too expensive.”
By contrast, USE-IT’s green, innovative and proven manufacturing system combines clay-bearing soil and waste builder’s rubble from landfill sites to form CEBs that are robust, durable, environmentally efficient and 95% recycled.
Says Chris: “Our blocks are made with locally available materials and our equipment is mobile to make use of the materials on site. There is no need to plaster our walls and we use the smallest possible amount of cement [5%] to stabilise the blocks. We do not need to fire the blocks and they cure in just seven days, ready to build. The process of building does not use a cement brickforce between the blocks, but rather a thin soil-slurry that is cheaper, quicker to use and bonds more strongly than cement. This allows us to train people within an hour to lay CEBs, eliminating the need for qualified wet-work artisans. There is no waiting for cement to dry between blocks because the slurry sets in under four minutes. In short, CEBs are greener, stronger and 16% cheaper than conventional equivalents,” explains Chris.
CEBs have now secured approval from the South African Bureau of Standards (SABS) as well as the National Homebuilder Registration Council (NHBRC) and Construction Industry Development Board (cidb), proving that the system is viable, certified and legal under the laws of South Africa. The system has also been proven. USE-IT has built more than ten demonstration structures in KwaZulu-Natal and is currently building its first demo unit for eThekwini Municipality. Given the challenges associated with getting alternative building materials through the bureaucratic process and low-cost housing tender system, this marks an important step forward. Meanwhile, the feedback on CEB houses built in the private sector has been very positive.
As Chris concludes: “We have proved that our system works and it works well. CEB technology has been used successfully in numerous countries worldwide. It has a vital role to play in meeting the demand for sustainable, affordable, environmentally friendly housing among South Africa’s low-income communities.”