SFS Infill Walling System
An SFS infill wall is a non-load-bearing wall of cold-formed steel studs and tracks, fixed between the floors of a concrete or steel primary frame. It supports cladding, sheathing and finishes — not the building’s structural load — and is widely used on mid- and high-rise projects for its light weight and fast, dry installation.
By Boyan Stanilov, Managing Director, BAS Frames · Last reviewed July 2026
Lightweight Steel Frame Infill Systems
Our Lightweight Steel Frame Infill Systems deliver fast, efficient weatherproofing solutions—achieving up to 50% quicker enclosure than traditional building methods, helping you meet tight project deadlines and reduce overall construction time.
Precision, Flexibility, and Structural Integration
Designed to seamlessly integrate with both concrete and structural steel frameworks, our infill system uses precision-cut studs assembled through a stick-build method, enabling rapid installation and swift weather-tightness. The system’s flexibility accommodates structural movement and varying degrees of deflection, ensuring durability and stability throughout the building’s lifecycle.
Cost-Effective Solutions for Mid-Rise Buildings
Paired with a broad range of sheathing boards, our infill solutions are suitable for mid-rise buildings up to and beyond 18 metres in height. This lightweight steel approach not only accelerates build progress but also offers significant cost savings—making it the smart choice for modern developments seeking quality, speed, and efficiency.
Common Applications of SFS Infill Systems
SFS Infill Systems are widely used across many building types due to their lightweight strength, precision, and speed of installation. They are commonly applied in apartment buildings, retail units, hotels, blocks of flats, leisure centres, schools, and a wide range of commercial steel frame buildings. As the construction industry increasingly adopts faster and more efficient building methods, the popularity of SFS infill has grown rapidly. With advantages including structural strength, design flexibility, rapid enclosure, and long-term durability, it’s clear why light gauge steel framing and steel frame infill systems have become the preferred choice for modern developments.
Benefits of SFS
Strength steel is extremely robust and can withstand massive loads compared to timber frame frameworks. Its greater density implies that steel frames, although heavier than timber or concrete, can support heavier loads on beams of similar dimensions.
Time-saving steel frames are prefabricated, which means they can be assembled (via welding or bolting) on-site.
SFS allows for a quick and easy installation when time is of the essence.
Flexible steel can be cut and adjusted to the exact specifications you want. It is therefore adaptable and suitable for a wide range of diverse designs. Using a steel frame allows you to build an extremely solid structure and bring a unique design to the world. Steel frames made of structural steel are easily adaptable or modifiable if any remodelling or expansion work is planned.
Durable SFS lasts much longer than concrete or timber. Steel is not prone to splitting or cracking as it ages. If the Steel is properly primed or finished, it will not be inclined to corrosion and will also not become warped or rot when exposed to humidity.
Cost-effective because SFS are manufactured off-site, you will be able to reduce your on-site costs. As we mentioned in the fourth point, Steel is extremely durable, so the costs for maintenance or repairs will be substantially smaller.
Sustainable Steel is completely recyclable, which will significantly reduce your carbon footprint.
Safe steel is a non-combustible substance that does not cause a fire. An SFS structure framing method can help protect the structural integrity of a structure when faced with extreme weather conditions.
Lightweight SFS Infill Systems
Our Lightweight Steel Frame Infill Systems provide a fast and efficient solution for modern steel frame construction, delivering up to 50% quicker enclosure compared with traditional methods. This SFS infill approach forms a lightweight yet robust steel frame structure, enabling rapid weatherproofing and helping projects meet tight deadlines while reducing overall build time. Designed to integrate seamlessly between concrete and structural steel frameworks, the system uses precision-cut studs assembled through a reliable steel frame stick-build method, ensuring exceptional flexibility and stability. Suitable for mid-rise developments up to and beyond 18 metres, this light gauge steel framing method supports a wide range of sheathing boards and offers excellent value for developers seeking quality, speed, and efficiency. With applications ranging from apartments and hotels to retail units, schools, and commercial buildings, SFS construction delivers proven advantages including strength, durability, adaptability, sustainability, and fire-resistant performance—making it one of the most effective and dependable steel framed building solutions available today.
FAQ
What is an SFS infill wall?
An SFS infill wall is a non-load-bearing wall built from cold-formed steel studs and tracks, fixed between the floors of a concrete or steel primary frame. It carries cladding, sheathing and finishes but not the building’s structural load.
Is SFS infill load-bearing?
No. An infill wall carries only its own weight plus the cladding and the wind load acting on the façade, transferring those loads back into the primary frame. Vertical building loads are carried by the concrete or steel structure, not by the infill.
How much faster is SFS infill than blockwork?
SFS infill is typically installed far faster than traditional blockwork and can run in parallel with other trades, helping weatherproof the building envelope sooner and protect the programme.
Where are SFS infill systems used?
Infill walling is used on mid- and high-rise residential, commercial and mixed-use buildings with a concrete or steel frame, where light weight and speed suit constrained sites.
Can SFS infill be used on buildings over 18 metres?
Yes. Infill walling is routinely specified above 18 metres, but buildings at that height fall under the Higher-Risk Building regime, so the wall build-up must be a tested system and the fire-safety evidence has to be documented for the Building Safety Regulator gateways.
What sheathing boards are used with SFS infill?
Infill framing is lined externally with a weather-resistant sheathing board — typically cement particle board, glass-reinforced gypsum sheathing or a fibre-cement board — selected for the fire, moisture and racking performance the façade build-up requires.
What is a deflection head and why does an infill wall need one?
A deflection head is the detail at the top of an infill wall that lets the floor slab above move without loading the studs. Concrete slabs deflect and creep over time, so the head track is designed with a movement allowance and a fire-rated seal, keeping the wall free of structural load while maintaining the fire and acoustic line.
Who designs the SFS infill — the subcontractor or the project engineer?
The project’s structural engineer sizes the primary frame and states the movement, wind and fire criteria; the SFS specialist then designs the infill itself — stud gauge and centres, head and cill details, cavity barriers and fixings — and issues calculations and fabrication drawings for approval.
Does BAS Frames design and install infill?
Yes. BAS Frames designs, supplies and installs SFS infill systems as a complete package, including deflection-head and cavity-barrier detailing and fire-safety documentation.
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