The advent of light steel frame building in South Africa is one of the most exciting developments in recent times in the steel and building industries.
SASFA, the Southern African Light Steel Frame Building Association, a division of the SAISC, the Southern African Institute for Steel Construction, was officially launched on October 18, 2006 to cater for this new (at least in South Africa) method of building. While it has been used in the US, Europe and Australia for decades, it was only recently introduced to our shores and offers quality, cost efficiency and speed of erection for low-rise residential and non-residential buildings
John Barnard, SASFA director, explains that, “In 2003, the SAISC identified the development of light steel frame building elsewhere in the world and realised that there was the possibility of a lively interest in South Africa. Hennie de Clerq, executive director of the SAISC and I spent two weeks in Australia visiting a number of light steel frame building companies and came back to South Africa with a wealth of knowledge.”
Light steel frame building consists of structural wall frames and roof trusses, manufactured from cold-formed light gauge galvanised steel sections. Exterior cladding can consist of a single skin brick wall or fibre cement board, fixed to the wall frames. Services – electricity and plumbing – are installed in the wall cavity created by the light steel frames, as is the insulation material. Gypsum board, fixed to the light steel frame, is typically used for internal wall cladding and ceilings.
According to Barnard, the reason for the adoption of this building system is the development of design software which is linked to specialised manufacturing equipment which ultimately reduces human error and saves construction time. “The use of the design software to drive the manufacturing equipment has ignited interest in the technology,” he says. “It results in properly designed buildings where factors such as wind speed can be inputted into the system and the structural needs calculated. Value wise, it cuts down on a lot of man hours. With regards to the skills of the contracting team, although it is a very simple way of building, one can make a mess of it quite easily, but when it is installed correctly, it is dimensionally perfectly accurate – everything is square and the walls are vertical,” he says.
“Light steel framing is being used in many applications, from complete structures in the mid to upmarket residential sectors through to emergency housing,” says Brent Harris, managing director of Vela Steel Building Systems. “Lightweight steel trusses are also being used extensively in the low cost sector. Other applications for light steel frame building include external and internal facade cladding for commercial and retail buildings.”
From a roofing perspective, Richard Bailey, general manager at Mitek Industries, says; “There is a fair amount of resistance from domestic clients and builders for steel light gauge trusses instead of timber. If accepted, they often insist on the overhangs being timber. However, money talks and it comes down to a price issue. In this respect, steel trusses were competitive with timber at the beginning of the year, but with steel having increased in price by about 60% this year domestic roofs are cheaper in timber.”
With regard to commercial offices and longer span industrial buildings, Bailey believes that clients and builders are less particular about the material in the roof, and are quite used to hot-rolled steel being used. In that case the price issue is the first one on the table. “If it is cheaper (and light trusses are generally 30 to 40% cheaper than hot-rolled solutions), then we can get in the door as the QS is then happy. We then need to sit with the structural engineer and answer all of his questions about the design, as engineers in general are not yet familiar with light steel trusses. If he gives his blessing, which he generally does if he has had a chance to ask his questions, then the sale happens. If the erection goes smoothly and everyone is happy, then obviously all involved are much easier to convince the next time a roof comes along. Slowly people are becoming more and more aware. The seminars and information sessions that SASFA are holding is giving the steel credibility and making marketing and selling it easier,” he says.
The involvement of architects
When asked whether he believes that architects are aware of the benefits of light steel frame building, Harris answers in the negative. “There are many architects who have only recently become aware of light steel frame building and many who are not aware of it all, let alone its benefits. Our company is in the process of designing three shopping centre expansion projects, and the lightweight nature of the building system enables the clients to expand over existing parking decks without having to extensively increase the support structures. The other major benefits of this building system include the speed of erection and the excellent thermal qualities of the insulated panels,” he says.
Bailey agrees. “Some are aware, many more are not. A lot of excitement has been generated about light steel in the last 18 months and that is helping. Architects though are more open to the concept than engineers, believe me,” he says. Barnard believes that there is still a lot of work to be done to bring the building method to the attention of architects, but with the draughting of a building code which is already at the SABS stage, he believes that steps are being taken in the right direction. “There are no constraints on the architect,” he says. “It is not a prefab system – you design your spaces exactly as you want – light steel frame building doesn’t preclude anything. The interest from architects is certainly apparent from the attendance of courses as half of the attendees tend to be either engineers or architects.” What about curves? Barnard laughs, “That is a question we get a lot from architects. And the answer is yes.”
“There are no restrictions to light steel frame buildings,” he continues. “We tend to only talk about low rise buildings of one or two storeys, but you can go higher. It is a bit more complicated and more engineering needs to be done, but we recently heard of an 11 storey building that was completed in China. The quality is inherent in the materials – the boards are SABS approved and the steel used is the correct strength.”
Adoption by the general public
“Timber is still number one for domestic roof truss use and bricks are still number one for walls,” says Bailey of the South African public’s choice materials. “But there are a number of individuals who are open to the idea of steel and clad walls and steel roofs, yet much marketing and convincing still needs to be done,” he says. Harris concurs with this assessment; “Building with brick is still a firm favourite as it is well entrenched in our society. However, more and more people are becoming aware of alternative building systems and their benefits. Government is also spending a lot of time and effort on investigating alternative building systems to meet their housing demand, and this is filtering through into the townships as well. Over the next few years I believe that light steel frame building will become one of the preferred forms of construction.”
This is good news, and it seems that contractors are also catching on. John Barnard explains; “I asked one of the first builders that did a light steel frame extension how he would summarise the experience, and he said, “Well, everything fits.” And that sums it up nicely for me.”
The environmental slant
“Someone referred to the constant barrage of environmental issues as a ‘greenwash’ of information,” says Barnard, “But in terms of the embodied energy of building materials, light steel frame building has advantages compared to other building methods. That is not to mention logistics and recyclability as most of the materials can and are being reused.”
Light steel frame building is sustainable for a number of reasons according to Harris. “Firstly, the insulation in the wall cavities improves the thermal efficiencies in the structure immensely. Secondly, lightweight steel structures can be built on elevated platforms, minimising the impact on the surrounding vegetation and an entire house can be transported in a flat-pack format on the back of a single truck, thereby minimising the impact on the roads and surrounding environment caused by heavy laden trucks belching out exhaust fumes. All of these factors should be taken into consideration when looking at the “green building” elements and carbon footprint,” he says. Bailey also points out that it is a greener alternative as the insulation properties can be adjusted depending on the insulation material used in cladding and inside the walls. “This costs more initially but saves heating and cooling costs later,” he notes.
With a number of light steel frame buildings in development, including a number of colleges and community type buildings, although residential is still the biggest market according to SASFA, the interest in this form of building is definitely on the rise. “SASFA’s main aim is to ensure quality, the one deficiency of the building industry at the moment,” explains Barnard. And introducing a new method of building to the country has its advantages. “It’s a new industry in South Africa so we can start off without any bad habits,” Barnard concludes.
* SASFA – 011-726-6111 or HYPERLINK “http://www.sasfa.co.za” www.sasfa.co.za
* Gyproc – 0860-27-28-29or HYPERLINK “http://www.gyproc.co.za” www.gyproc.co.za
* Mitek Industries – 011-237-8700 or HYPERLINK “http://www.mii.com/southafrica” www.mii.com/southafrica
* Vela Steel Building Systems – 011-397-8742 or HYPERLINK “http://www.velasbs.co.za” \t “_blank” www.velasbs.co.za
Lightsteel1.jpg: One of the completed homes at Arlington Estate, near Broadacres. This is a steel frame home with a loft room – the strength and design of the steel frame roofing system allows for 20% more volume (than traditional wooden roof trusses) that can be comfortably utilised for living space in the roof. Pic courtesy Gyproc
Lightsteel2.jpg: The roofing system of the multi-purpose hall at the Swaziland School for the Deaf. The span is 17,5m and the roof covering will be IBR sheeting. Pic courtesy Mitek Industries
Lightsteel3-6.jpg: A house in Pretoria North which shocases the versatility of light steel frame building.