Lightweight steel housing catches on in South Africa

24th November 2006

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, says John Barnard, director of Southern Africa Light Steel Frame Building Association (Sasfa), a newly-formed division of the Southern African Institute of Steel Construction (SAISC).

“While this method of building has been used in the US, Europe and Australia for decades, it was only recently introduced in this country. It offers quality, cost-efficiency and fast-track erection for low-rise residential and nonresidential buildings,” says Barnard.

SAISC executive director Hennie de Clercq says that the technology of light steel-frame building could make a palpable difference to the delivery of houses in South Africa.

He says that when the mindset of saving money in the short term changes and a more intelligent long- term view of overall energy saving over the life of a building is adopted, the many advantages of this technology will be embraced by the industry.

“A long-term view of overall energy expenditure, whether this is the natural entropy of material on the one hand or heating and maintenance costs on the other, is more commonplace in places like the US, Europe and the East.

“There, investors, especially in housing, have learnt that trying to cut corners on the initial investment is sometimes the most expensive option in the long term. With lightweight steel-frame construction, the long-term financial benefits are incomparable,” he says.

Light steel-frame building consists of structural wall frames and roof trusses manufactured from cold-formed thin-gauge galvanised steel sections.

Exterior cladding can consist of a single-skin brick wall or fibre cement board fixed to these wall frames.

Services like electricity and plumbing are all 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 to provide a perfect finish for internal wall cladding and ceilings.

“The key to the success and rapid growth of light steel-frame building worldwide lies in a seamless interface between the computer-based design and the computer-controlled manufacturing facilities,” says Barnard.

He adds that sophisticated software design programs have been developed to carry out the structural design of each element required for a building and to electronically convey the dimensional specifications to the roll-forming facility.

Barnard reports that there are sev- eral advantages of light steel-frame building compared with conventional building in terms of quality, cost, durability and speed. Some of these include:

• The quality complies with the design requirements of the National Building Regulations.

• Each structure is signed off by a structural engineer.

• Only quality-certified materials are used.

• Frames are assembled under controlled factory conditions.

• In the case of poor foundation conditions, steel-framed buildings can accommodate significant movement without cracking.

• The steel frame dictates a high degree of accuracy of building dimensions, with the result that everything fits as planned.

• Time saving can be as much as 30% when compared with conventional building.

• Structures are lightweight. A steel- framed wall, clad with fibre cement/plaster board, offers a mass saving of 90% compared with a double-skin brick wall.

• Approximately an extra 4% floor space is obtained owing to reduced thickness of external walls.

• Services are installed in the wall cavities without the necessity for chasing the walls.

Quality assurance

“All these advantages combine to reduce wastage, lower logistical costs and reduce time of construction.

“So while the materials in themselves may not be less expensive than brick and mortar, there are savings to be made in the construction process and, of course, the quality of the entire structure ends up significantly better than a conventional one,” says Barnard. He adds that Sasfa will play a major role in ensuring that quality standards are maintained in the light-weight steel-frame building industry and that all legal constraints to this revolutionary building method are challenged in the proper manner.

“The benefits of this method are significant for the delivery of houses and other low-rise structures in the country and we will do all we can to promote the local industry, both internally and for export, while helping to ensure an ethical approach to business in the industry,” he concludes.