SA Affordable Housing May - June 2019 // Issue: 76 | Page 28

FEATURES
they would not have been able to do had they used
traditional building methods.
With its installed insulation, LSF buildings are more
energy-efficient than heavy masonry buildings. A research
project carried out by the Council for Scientific and
Industrial Research (CSIR) for SASFA, indicated that an LSF
building will require less than half the energy needed to
heat and cool an uninsulated masonry residential building.
“The use of LSF allows for energy conservation on two
levels. The energy used in the manufacture of the actual
building materials – the embodied energy – is considerably
less than the amount consumed by traditional building
materials. Secondly, the operational energy used in heating
and cooling the building over its lifespan is also
considerably less.
An LSF building is dimensionally far more accurate than
masonry building or concrete construction. This saves time
and cost when installing pre-made components such as
kitchen cupboards and wardrobes. "With light steel framing,
one can work to a tolerance of less than +5 mm,"
says Barnard.
With a comparatively new building technique such as
LSF, training contractors is essential. To this end, SASFA
presents a five-day training course in light steel frame
building. The course is split into two sections:
• Steel frame materials, components and erection
• Internal lining, external cladding and insulation
The course is growing in popularity (the most recent one
being fully subscribed), as an increasing number of building
contractors, developers, architects and engineers wish to be
more knowledgeable about LSF construction.
"It has indeed been exciting to see – and hear about – the
progress that the cold formed steel industry has made since
SASFA's inception. Some of these highlights include the
development of the light steel building code, the
introduction of cold formed steel into building façades, the
acceptance of the benefits of light steel framed homes and
the growing number of light steel frame projects being
completed," says SA Institute of Steel Construction CEO
Paolo Trinchero.
"In addition, SASFA’s ongoing education programme for
the construction industry and allied sectors is proving to be
very effective in growing the awareness of the features and
benefits of light steel framing, and providing the skills
required to efficiently build using LSF."
"Whereas initially, LSF construction was only used for
smaller building projects in South Africa, it is now being
used for the complete spectrum of construction projects,"
continues Trinchero. A milestone achievement for light steel
frame construction in South Africa occurred when the
building technique was used to supply and install a
lightweight steel façade wall and parapet structure at the
Mall of Africa in Midrand.
"This is one of the largest single phase shopping mall
building projects ever undertaken in South Africa and
certainly the largest and most prominent LSF project to date
in this country," Trinchero comments.
ACCEPTING DIFFERENT SOLUTIONS
As with most alternative building solutions, there is still
resistance from developers and home owners to anything
except brick and mortar. Changes in mindset take time.
South Africa, historically, has a double brick wall mentality,
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MAY - JUNE 2019
A three-storey accommodation block built by SANDF in Durban.
which will change only gradually once the benefits of the
alternative building systems are realised and experienced.
“As SASFA, we have had feedback from a number of brick
builders after using light steel frame building, in which they
claim that they never want to go back to brick and mortar.
Light steel frame building is fast, clean, produces less
rubble, less rework and is accurate. Quality control largely
happens in the factory where the LSF is manufactured,”
Barnard comments.
He continues, “I once accompanied an American
colleague visiting South Africa to look at light steel frame
projects in Waterfall Estate, Midrand. We drove past a brick
and mortar building site, and she asked me to stop. She
could not believe that we are using double leaf brick walls!
They of course [Americans] have a history of frame building
– steel or timber. Once the requirements of SANS 10400 XA
(energy efficiency) are enforced, we predict that there will
be a greater move to light steel frame building locally.”
STRUCTURAL STRENGTH
AND MULTI-STOREY APPLICATION
LSF is manufactured using high-strength galvanised steel
sheet – with a yield strength of 550MPa compared with
355MPa for ‘normal’ structural steel. That means
thinner gauge G550 material can be used for the same
load-bearing capacity.
LSF structures are actually designed to resist design
forces, unlike masonry buildings which rely on the mass
of the bricks or blocks and empirical rules to resist
horizontal forces.
Load-bearing LSFB has been used for up to three-storey
buildings in South Africa. It is also used in conjunction with
welded ‘heavy’ steel structures, or reinforced concrete
frames for taller buildings. For example, the external
cladding of the 12-storey Assupol building in Pretoria.
In the US, LSF building is used in up to nine-storey
buildings – the LSF sections of the lower storeys are made
using thicker gauge material; and the studs are spaced
closer than our standard 600mm to carry the increased
dead, live and wind loads. Bracing the building is of course
also more complex than in the lower rise structures.
"The growth and popularity of LSF construction in South
Africa is a phenomenon that needs to be both welcomed
and embraced. It is a highly efficient building and
construction technique, which will provide South Africa
with a more affordable means of constructing both our
residential and commercial properties in the future,"
concludes Trinchero.
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