Light steel frame components can be used as a direct replacement for structural walls as either fully load-bearing structures with external facades or as secondary components in load-bearing frames. These frames are formed from galvanised steel plate up to 4mm gauge as studs at a maximum of 600mm centres.
LSF walls can also be used in volumetric modular construction as either primary components to form the box structure or as walls within a bed-stead type frame. [Refer to Section ‘Components for Modular Construction’ later in this guide for more detail
All wall types are lined internally to provide fire and acoustic performance and externally to accommodate facades and provide racking as required. LSF manufacturers and lining board providers have fully tested loadbearing walls to BS EN 1365-1.
Walls forming full load-bearing structures Load-bearing structures are designed and installed to relevant codes and standards, to create full structures to which facades are then applied. LSF
frames and components are combined to form external, separating and internal walls. Lift shafts and stairwell walls can also be formed along with those required to form shafts and risers.
Separating walls can be formed as either a single or twin leaf frame depending on the level of acoustic performance required. Walls are formed using vertical studs at a size and centres determined by the structural engineer. Bracing may be required to ensure the structural integrity of the walls which can be in the form as either steel profiles within the stud zone, cross bracing on the face of the wall or by racking boards.
Infill and oversail walls
Walls are used to replace a blockwork skin in steel or concrete frame host structures. This results in reduced load on the primary frame, whilst being robust enough to accommodate the external cladding. For infill walls components are typically fixed between the host structure main frame, whereas in oversail the components are fixed on the outside face of the frame.
Components are supplied to form a structural stud facade system commonly used in two main methods – Infill and Oversail. C-shaped studs and U-shaped tracks are designed on a project specific basis to form the inner leaf of an external facade.
Both systems are constructed on-site and as load-bearing structures are designed and installed to relevant codes and standards. Sections are supplied to site as individual components and fully assembled in-situ. Components can be supplied in final required lengths or standard lengths cut to suit on-site.
Infill
Components are typically supported at the slab edge between the host structure formed in either hot-rolled steel or concrete. This allows insulation and external finishes to be installed outside the main structural frame. The system is suitable for both low and high-rise construction.
It should be noted that deflection allowance is required at each floor level.
Oversail
Components are fitted outside the line of the structural frame using support cleats at each floor level with connections designed to allow slab deflection. It is particularly suited to situations where cladding materials are sensitive to differing movement of the main frame.
It should be noted that adequate base support must be provided to accommodate vertical loading.
Facades to LSF walls
LSF walls used in the applications noted can accommodate the following cladding types:
• Masonry*
• Brickslip systems
• Insulated render
• Metal rainscreen cladding
• Terracotta rainscreen cladding
• Timber rainscreen cladding
NOTE: LSF will not generally be designed to accommodate loads, other than lateral restraint for the masonry skin.
Walls are fixed down to the substructure and interconnected to form the structure with either screws or bolts.
Floors in load bearing systems can be formed as either a platform structure where the floor sits on top of the wall, or as a balloon structure where the floor is fixed to the side of the wall with or without using zed hangers.
Steps and staggers can be accommodated within the wall layouts to meet the architectural requirements and to suit the topography of the site.
Image credit: Sigmat
