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Most countries face a massive move of people away from rural areas to urban areas; the majority of people worldwide currently live in urban areas. Thus a crucial planning imperative is to investigate how urban growth can be made more effective, especially regarding poverty alleviation, and how new forms of urban growth can be developed cost effectively.
The CSIR is researching solutions, through a pilot project, to some of the problems typically experienced with subsidy housing. The pilot project stems from a Department of Science and Technology (DST) contract where the CSIR will assist in evaluating the efficacy of alternative technologies to scale-up poverty-reducing measures and improve the sustainability of two housing projects, namely Kleinmond in the Western Cape and Mdantsane in the Eastern Cape.
"If we look at self-sufficiency of housing development in the two areas, it must aim to include socio-economical, environmental, technological and ecological issues," explains Llewellyn van Wyk, CSIR architect active in the construction area. "To achieve this, certain basic research questions must be answered, such as what the thresholds/tipping points are of the approach (income, rainfall, wind speed, number of solar hours, number of units, size of land, access to jobs); and what technology is available to extend and maximise these thresholds."
To assist research into innovative technologies in general, and their performance-enhancing capabilities in particular, the CSIR has built two pilot houses on its test site in Pretoria to investigate technology options.
In recommending technologies to the DST, a fundamental component of the CSIR's research is addressing anticipated energy and water shortages facing the country. Certain technologies that are known to offer other benefits, such as job creation, are also being targeted. Similarly, the potential of the specific geographic conditions of the sites and the surrounding areas - for example local soils - must be investigated to see whether it could add value to the development. The location of the sites and the connections of these to existing and adjoining sites - such as public open space systems - must also be explored to ensure that these connections are maximised.
"For our development proposal to serve as a model, it must not burden the financial sustainability of local authorities. One of the ways this can be done is to reduce the dependence of the development on municipal services," comments Van Wyk. "You could, for example, use a range of technologies such as wind generators in conjunction with solar collectors. The introduction and implementation of sustainable urban drainage systems can also be considered together with a range of water treatment technologies."
Scaling up approaches
The preferred means of scaling up the pilots is through local, provincial and national level involvement - using the pilots for demonstrators that can be managed and expanded by governments.
Three types of packages can serve as possible scaling-up options. Type I follows rigorous monitoring of technology, quantifying the outcomes of these and establishing proof of concept.
Based on the experience gained in the type I approach, the cluster approach - or type II approach - will focus on scaling up the integrated, community-based strategies for achieving sustainable communities around type I approach projects. The type II approach is also proof of concept but at a scale of 10 times higher. Aims of type II include the understanding of technology interventions that need to be provided at a district level (e.g. transport infrastructure, electricity generation and distribution, rainwater harvesting, sustainable urban drainage systems), and thus benefit from economies of scale.
Type III will replicate and scale-up successful integrated, community-level interventions to achieve sustainable communities beyond the immediate vicinity of types I and II.
Kleinmond and Mdantsane housing developments
The Kleinmond housing development comprises 585 housing units. The additional capital budget value is R18,5 million. The Mdantsane housing project is for 2 005 housing units, with an additional capital budget value of R16 million.
"We propose that type I is used for these two developments, not pursuing radical technologies but rather value-addition through proven fringe technologies incorporated in the current design and construction of subsidy houses," says Van Wyk.
The following technologies and best practices will be evaluated for implementation in the housing projects:
- Use of local materials: The geotechnical report indicates that the local soils are suitable for use in the construction of the roads within the housing project, thus saving the need for in situ material to be carted away, and new material to be imported from borrow pits.
- Road widths and surfaces: The CSIR is suggesting that trafficable road widths be reduced to 3,5 m for service roads and 5,5 m for feeder roads. The difference between the road reserve and the road surface will be compacted and used for parking purposes.
- Urban drainage: The CSIR recommends that storm water be collected and made available as a water resource. As associated problems could include contamination caused by faeces and other wastes, it may be that storm water from above the site is diverted and collected. The implementation of reed beds for soiled water treatment will also be investigated.
- Energy: Small-scale wind generators, solar hot water heaters, low-energy fittings and gas cooking units could be included in the development. The combination of reduced internal energy demand due to improved thermal insulation and low-energy fittings, coupled to energy generation of solar and windmills, offers an opportunity to reduce the frequency of outages within the community while reducing energy costs to the occupants.
- Housing construction: Investigations focus on the three main components of housing construction, namely sub-structure (foundations, foundation walls, and foundation slab), super-structure (walls, windows, doors up to wall-plate level), and roof structure (trusses, purlins, roof sheets, gable walls). Each component is evaluated to minimise construction material and time, while improving construction quality and indoor comfort.
- Manufactured construction technology: As many of the construction elements as possible should be constructed on a modular basis and assembled on site as prefabricated elements. These include prewired electrical wiring looms, preplumbed water and drainage runs, roofs and infill panels.
To undertake this research, a standard low-cost housing unit has been built, together with a suburban variation of the same house plan. This is being done to establish two benchmarks, namely typical performance values of a current low-cost housing unit, and typical performance values for an equivalent suburban house using conventional housing technologies. The research seeks to determine whether technology interventions can be developed and introduced to improve the performance of the low-cost house to that of the conventional house without substantially increasing construction cost.
"Our two pilot houses will be monitored for performance of technologies and best practices for a minimum period of 12 months. We are already encouraged by the lessons obtained in the construction phase, even though we have been busy for only five months. We are also greatly encouraged by the interest shown by our industry partners, many of whom are participating with the CSIR in investigating new technologies in situ. Once the concept is replicated in the Kleinmond and Mdantsane housing developments, we hope to engage with the DST and other partners regarding a 10-year scaling-up effort across South Africa," Van Wyk concludes.
Enquiries: CSIR Communication
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