The role of the South African precast concrete industry continues to gain in scope and significance, a fact for which there is ample evidence in this year’s CMA Awards for Excellence competition. In this precursor to the awards, Leading Architecture showcases some of the favourites for top honours.
Whatever the application, the 12th CMA Awards for Excellence competition bristles with innovative endeavor, demonstrating the local precast concrete industry’s dedication to providing better more eco-friendly building solutions at quality levels which in most instances rival international standards.
In paging through the 2008 Awards for Excellence entry book, one is immediately struck by a diversity of product and application, evidence that all sectors of South Africa’s multi-faceted demographic mix are benefiting from the substantial investment that goes into finding new applications for and improved performance of precast concrete.
Take concrete roof tiles for affordable housing as an example. One of the projects entered in this year’s competition was an economic housing development, the Olievenhoutbosch Ministerial Housing Project on the R55 north of Sandton. When completed at the end of 2008, some 1 410 000 Marley Double Roman Plus concrete tiles in a variety of through-colours will have been used to roof close on 3 000 housing units.
CMA director, John Cairns, says a mere four years ago the use of concrete tiles as the default roofing material for economic housing would have been considered a pipe dream, whereas today projects such as Olievenhoutbosch are the norm. “As a result of research conducted by the CMA and our members into alternative types of roof truss systems, concrete roof tiles have become the most cost-effective roofing material on roofs built with trusses. Moreover, they offer other advantages such as excellent aesthetics, low maintenance and good insulation properties.
Cairns says another competition entry, this one falling under the Innovative Concrete Products/Applications category, demonstrates conclusively that precast concrete’s footprint is indeed on the expansion trail. “It concerns the use of precast hollow-core slabs in building the wall and roof of a water reservoir. Before this project only reservoir roofs had been built with precast slab technology locally. Situated in the Free State town of Lindley, the circular wall took only three days to erect using slabs manufactured by CMA member, Stabilan, and the entire project only seven weeks to complete. Traditional shuttering would have required four 1.2m lift sections, each of which would have taken +- seven days to erect. As a first of its kind, the project involved a learning curve for all participants. Future reservoir projects using precast slab technology on the walls, columns, beams and roofs will be much quicker,” he says.
This year has also witnessed the frontiers of the traditional usage of precast hollow-core slabs being widened. Bridgeview, a five-storey high density apartment block in Braamfontein, Johannesburg, has become South Africa’s tallest structure built using precast hollow-core concrete floor panels. Two cranes were used to hoist a total of 5 848m² of 150mm slabs, manufactured by Echo Prestress, into position. A balcony over-hang effect was achieved with cantilever steel beams to create the illusion that the slab is free-hanging. Cairns says Bridgeview’s success will act as catalyst for further such development which could be as high as six or even seven-storeys.
Precast concrete seating has been specified on most of the stadiums being built for 2010 and some of these were entered into this year’s competition by Concrete Units and Infraset. And in another soccer stadium entry, the Moses Mabhida Soccer Stadium, precast concrete façade columns manufactured by Group Five were used to great effect.
Cma1.jpg: The Skemerzicht Group Housing Scheme in the Western Cape where 32 duplex houses were built with an external skin of Western Granite Chardonnay Rockface bricks. The architect chose the brick because it is maintenance-free, has a natural light colour and has no comebacks on colour variation.
Cma2.jpg: The Plot, a spacious five-bedroomed home in Jeffrey’s Bay, is a fine example of how concrete stock bricks are making inroads into the up-market residential construction sector. Some 400 000 concrete stock bricks were supplied by Concor Technicrete for the construction of the house.
Cma3.jpg: The construction of Forest Glen, a 64-unit townhouse complex in Paradise Valley near Pinetown, KwaZulu-Natal, on a steeply sloping site presented an unusual set of challenges for the contractors, CBD Building Projects. The houses were not based on conventional wall-above-wall designs and the rooms above the ground floor units differed in size and layout. The problem was solved with architectural benefits by using 200mm thick prestressed concrete floor panels manufactured by Echo Prestress in Durban.
Cma4.jpg: Kingston Place, Marina Martinique, Jeffrey’s Bay, where Neat Contech’s Econodek 600 plank and block suspended flooring system was used in the construction of 12 three-storey apartment blocks. A total of 2 580m² of the Econodek system was used on this 12 block development, and the longest span was 5,090m. As the walls were 220mm thick the erection of the slabs was both quick and easy.
Cma5.jpg: House Cooper in Kyalami, Gauteng where Smartstone’s Katze Cladding was used to create various feature walls. The random natural stone appearance of the cladding provides a good contrast with the straight modern lines of the house.
Cma6.jpg: This 600m fence at the Ligbron Academy of Technology at Ermelo shows off Concor Technicrete’s palisade concrete fencing to good effect. A tan pigment provides a cheerful appearance which has been achieved without any reduction in strength. Each two metre palisade has eight palings instead of the previous nine and the weight of the concrete beam cross-sections has been reduced.
Cma7.jpg: Infraset’s Terraceblok was chosen for the retaining wall at this Barli style cluster house development in Bedforview Johannesburg. The developer was looking for a very specific look and Infraset was asked to identify which block should be used. The double terrace lends aesthetic appeal to the property.
Cma8.jpg: The Kanonberg Lifestyle Estate where this set of retaining walls skilfully breaks up the embankment behind and to the sides of the house. Terraforce L11 and L12 were used by retaining wall contractor, Decorton, to construct the walls. The terraces are linked to each other by a 4X4 multi-step block system, also manufactured by Terraforce, which creates effective access and seating opportunities. Once the walls were completed a lush informal Moroccan-styled garden was created by Gardening Adventures.
Cma9.jpg: The Corners, an apartment complex in Ferndale, Johannesburg, where Bosun Brick’s Rio Rocoso Interlocker paver in multi-blend was used to pave the parking and other communal areas.
Cma10.jpg: Concor Technicrete’s Concor Trojan pavers were chosen for their natural, earthy appearance in the paving of this driveway and parking area of a house situated in the new Uitsig Landgoed development near Nelspruit.
Cma11.jpg: Marley Roofing’s Modern Terracotta tile is an important feature in this up-market cluster home development, Tezula, situated in Fourways, Gauteng. The roof pitch shows the character and beauty of the tile to its fullest advantage without compromising the overall appearance of the development.
Cma12.jpg: This prestigious residence, located in a new up-market housing development in Rustenburg required a finish that matched the rural surroundings. Concor Technicrete’s Concor Bold Double Roman roof tiles were the ideal choice, their rich antique tone enhancing the architecture of the house.