South African light-steel frame (LSF) construction company Futurecon completed the construction of a R7-million 454 m2 facility in Tshwane for optometric service provider Spectacle Warehouse last month.
Project architect Base Architects & Associates MD Darren Ogden explains that the only bricks used in the project were to build an access ramp for people with disabilities. The structure of the building is made with LSF and is insulated with cavitybatt glass wool wall insulation. The external enverlope is made using oriented strand boards (OSB), an engineered wood board. On top of the OSB is moisture membrane Tyvek, with a final finish of plaster mesh and render, fibre-cement handy planks or chromadek sheeting.
Futurecon director Mitchell Walker points out that, because plaster is the hardest part of the company’s building system, it has had to find innovative ways to prevent cracks from occurring.
“On top of the projection plaster and wire mesh solution, we applied a base coat and final render, providing multiple layers of plaster. Previously, we would just plaster directly onto the fibre-cement board, which was too rigid, causing it to crack,” he explains.
Spectacle Warehouse’s new building also has a 30 000 ℓ rainwater harvesting and water reticulation system, which will significantly lower the building’s demand for municipal water. In addition, one of the façades of the building has been fitted with solar-strengthened glass windows, which will improve the thermal properties of the building, thereby reducing demand for air conditioning.
The 161 m3 concrete base on which the building is situated will be used for parking. The building is constructed on a 400 m2 concrete slab 3 m off the ground.
The project took a total of six months to complete, with the concrete deck and columns taking two months and the building erection the remaining four months, requiring only 12 skilled workers to complete.
Meanwhile, Ogden points out that using LSF to construct buildings has many benefits over traditional brick-and-mortar-type buildings.
“The largest cost on a construction site is time. LSF structures are about nine times lighter, are erected significantly faster, generate less waste and have significantly better sound- and heat-insulating properties, compared with traditional brick-and-mortar buildings,” he asserts.
All steel is cut to size before being delivered to site, limiting human error when cutting and sizing material, as well as reducing the amount of waste generated on site. The walls come in a flat-pack bundle with joints, studs and noggins, which are all numbered. This allows for the walls to be erected in a predetermined sequence, significantly reducing the number of tools needed on site, as everything is prefabricated.
Because of LSF being so lightweight, Ogden highlights that building designs can be pushed further than when using traditional, heavier materials, adding that the benefits and adoption of LSF in other parts of the world, such as the US and Australia, show that this is the future of construction.