THE existing 3 storey building on the site has been re-engineered into a 5 storey structure, using heavy structural steel and precast concrete floors. It was decided that light steel framing would be used for all façade walls, due to its low mass, insulation, speed of construction and the ability to install LSF without impacting on other concurrent building activities.
Castle Properties is the owner / developer, and Capitalgro Property Management the principal agent. iBuild SA was appointed to carry out the wet trades. Having started concrete work in September 2020, it is planned to complete the building by October 2021.
Portland was appointed to supply the precast floor slabs, and Ekcon Engineers and By Design (LSF) as the structural designers. LRJ supplied the hot rolled steelwork, and Futurecon the light steel framing.
The light steel frame walls consist of LSF wall panels, supplied by LSF Co and delivered assembled to the site. Internal lining of the wall panels consists of fire rated gypsum board (15mm thickness). Rockwool insulation (100mm) is installed in the wall cavities to provide thermal and acoustical insulation. It was decided to use Tyvek vapour permeable membrane, with OSB and CaSi board fixed to the external face of the LSF, with profiled 0.53mm pre-painted galvanised sheet (Chromadek) serving as weather resistant and durable external cladding.
The LSF wall frames were manufactured to fit in the openings between floor and soffit – which were measured accurately using a 3-D scanner. The frames were anchored to the floor slabs using chemical anchors, and fixed to the soffits using Rawl bolts.
Standard drywalling is being used for internal walls, to allow for flexibility in floor layout to suit future tenants.
While the building process was underway, it was decided to add a sixth floor to the building! Due to its low mass, structural rigidity and ease of handling, it was decided to use LSF wall panels for the extra floor. LSF roof trusses will be used to support the saw tooth roof structure.
The addition of a floor to the top of the building using LSFB illustrates a huge potential market for developers! There are thousands of buildings where LSF can be used to add a top floor, or two, to create office or residential space.
- Information supplied by J Barnard, Director SA Light Steel Frame Building Association. Tel: 083 468 1410
