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Housing from industrial by-products

24 November 2011

Using by-products of mining and manufacturing, a group of South African companies has devised a more cost- and time-efficient way of easing the country's affordable housing backlog.

Cosmo City, a mixed-income settlement in north-west Johannesburg, has been chosen as a launchpad for a pilot project of affordable houses made from mining and manufacturing by-products.

The houses, which cost between R300 000 and R450 000, are built using fine ash from waste products from the coalfields of petrochemicals giant Sasol in Secunda, Mpumalanga province.

The ash is mixed with cement to form a rich foam held together by a polymeric binder, instead of the conventional brick and mortar.

"The entire foamed mixture is encased in a steel frame structure and this comprises a panel that can be used for any fit-for-purpose building application," says Marcel Hunt, a business analyst at Sasol ChemCity.

The walls and roof of the house, which is 85 square metres in size, are made of steel and take about five days to assemble, bringing about significant savings in construction costs and energy use, Hunt explains.

The housing project is sponsored by First National Bank and Sasol, while the technology used is developed by Tower Technologies, a subsidiary of EnviroServ Waste Management.

Technology

Hunt says the bank and chemical company joined forces to pioneer this technology in an attempt to ease the backlog in South Africa's affordable housing market, and to seek accredited alternative technologies to build affordable homes. The affordable housing backlog in the country numbers around 2.5-million.

So far, about seven houses have been built countrywide using this method: three in Cosmo City which have already been sold, and about four in Polokwane in Limpopo province. Hunt says more than 50 orders have already been made and there are about 120 on the waiting list.

This technology is not new, she adds, but for it to flourish a fully dedicated factory would have to be built to manufacture the pre-built panels from waste streams, fly ash, gypsum and the fine ash cement.

Fly ash is a by-product of Sasol's energy production, and gypsum is a by-product of industries such as paper making, fertiliser production and desalination of acid mine water.

"Until a factory can be built for the manufacture of these panels, no form contracts can be put in place," says Hunt.

The managing director of Sasol ChemCity, Bridgitte Backman, adds: "Taking this innovation from idea to market has been particularly rewarding."

Jobs

By supporting the development of this technology, Sasol aims to not only create jobs but also reduce its environmental footprint, says Backman. "A number of entrepreneurs and private institutions are additionally starting to explore the affordable housing space, identifying it as a market that is ripe with potential."

Marius Marais, the chief executive of FNB Housing Finance, says the method was considered because conventional building methods are becoming increasingly expensive, and directly affect the ability of banks and developers to meet the country's need for affordable human settlements.

"Because of this and continued increases in labour costs, we have been compelled to consider alternative technologies that will enable us to deliver affordable quality houses to the emerging middle class," Marais says.

Hunt explains that the steel panels used to make the walls can be used in any housing application. "Various factories can be set up according [to the] acquisition of a licence to manufacture and this can be rolled out nationally."

One factory producing four houses will have the potential to create about 96 permanent jobs.

The technology has provided bondable houses that are 10 to 20 percent cheaper than conventional houses but still deliver on quality and meet all building accreditation criteria of the South African Bureau of Standards (SABS) and the National Home Builders Registration Council, Hunt says.

Cement

Distinguishing factors between this method and conventional building is that this technology uses 25 tons less cement; the houses are thermally superior; they are monolithic; they are similar in look and feel to brick and mortar, with added benefits of quick delivery in building times; and panels equivalent to four 62 square metre houses can be easily transported to site.

Mike Symons, the chief executive of Tower Technologies, says this building system has many superior attributes in that the walls are guaranteed straight, are solid and are incombustible.

"The panels are factory manufactured to ensure consistent quality and render an 80 percent weight saving to conventional building methods, which makes it logistically efficient. The panels are manufactured from waste streams and therefore ensure a low carbon footprint, and have been fully SABS tested and Agrément certified."

He says this building system ensures a cost saving of between 10 and 30 percent compared to conventional building systems, depending on locality. It is also being licensed to prospective manufacturers countrywide.

Factory

Hunt says that because the panels are made in a factory, quality control is easier, adding that the housing structures have passed the same strength tests as conventional brick and mortar, and performed better under SABS testing than brick and mortar.

Rivash Panday, the waste management support team manager at Sasol ChemCity, says plumbing and electrical pipes are fitted into the steel panels and a separate constructor builds the foundation using conventional methods.

"Once the foundation has been laid it takes a day to put up all the panels. On the second day we put up the roof structure, and on the third day we apply the plaster. So in about a month the whole structure is ready, as opposed to the three months one would have to wait for a conventional house."

Panday says that for this technology to fully thrive, funding is needed to establish a factory where all building materials can be manufactured at once.

FNB's Carol Nkosi, who markets and sells the technology, has bought one of the three properties in Cosmo City. She says they are fully ventilated and comfortable.

Since going on to the market, Nkosi says, there has been a stream of requests and applications. Most keen buyers are between the ages of 35 and 45, are mostly second home buyers, and earn between R15 000 and R50 000 a month.

Source: City of Johannesburg