Steel Frame
Flooring Systems
Residential Floor Framing System — cold-rolled C-Joists and C-Bearers with Steel-MAX™ FCB3 brackets, extended bearer brackets and lateral end restraints. Spans 3.2 m to 6.2 m at 450 mm centres; extended bearers to 8.0 m. Suitable for Class 1a dwellings per NCC. Australia-wide supply.
AS/NZS 4600 & NASH Pt 1
Designed to AS/NZS 4600 Cold-formed Steel Structures and the NASH Residential & Low-rise Steel Framing Standard Part 1.
Spans 3.2 m – 6.2 m
C-Joists span 3.2 m to 6.2 m at 450 mm centres. Extended bearer options available to 8.0 m.
G550 / G450 Z350 Galvanised
550–450 MPa yield strength with Z350 zinc coating (350 g/m²) per AS1397 for long-term sub-floor durability.
Steel-MAX™ System
Complete system: C-Joists, C-Bearers, FCB3 brackets, extended bearer brackets, lateral end restraints and fasteners.
Steel Floor Framing — Standards & Specifications
The Residential Floor Framing System is designed and manufactured to current Australian Standards. The following reference data supports engineers, certifiers and builders specifying cold-formed steel floor systems for residential construction.
Applicable Standards
| Standard | Title | Application |
|---|---|---|
| AS/NZS 4600 | Cold-Formed Steel Structures | Design of all C-Joist and Bearer members |
| AS1397 | Continuous Hot-Dip Metallic Coated Steel Sheet & Strip | Z350 zinc coating specification for joists and bearers |
| NASH Standard Pt 1 | Residential and Low-rise Steel Framing — Design Criteria 2005 | Primary design standard for the floor framing system |
| NCC Vol. 2 | National Construction Code — Class 1a Dwellings | Performance requirements; system suitable for Class 1a only |
| AS4055 | Wind Loads for Housing | Design limitation: building must conform to Clause 1.2 |
| AS3566 | Self-Drilling Screws for Building & Construction | Class 2 (sheet flooring, internal) / Class 3 (connections) |
| NCC Vol. 2 Pt 3.4.1 | Sub-floor Ventilation Requirements | Ventilation details for sub-floor clearance compliance |
Materials Specification
| Component | Grade | Min. Yield | BMT Range | Coating |
|---|---|---|---|---|
| C-Joists (light) | G550 | 550 MPa | 1.0 mm | Z350 per AS1397 |
| C-Joists (heavy) / C-Bearers | G450 | 450 MPa | 1.2 – 2.4 mm | Z350 per AS1397 |
| FCB3 Brackets / Accessories | G300 / G450 | 300 – 450 MPa | pressed steel | Min. Z275 |
| Extended Bearer Brackets | G300 / G450 | 300 – 450 MPa | pressed steel | Min. Z275 |
| Lateral End Restraints | G300 | 300 MPa | pressed steel | Min. Z275 |
| ZAM® option (adverse envs) | ZAM® | — | as per section | ZAM® zinc-aluminium-magnesium |
Span & Performance Reference — Steel Frame Floor System
Based on cold-formed steel floor framing technical data. Confirm with engineer for your specific project.
| Parameter | Value / Requirement | Notes |
|---|---|---|
| C-Joist span range | 3.2 m – 6.2 m | At 450 mm centres; custom cut to nominated length ±10 mm |
| Extended bearer span | Up to 8.0 m | Extended bearer bracket required; connections by building designer |
| Joist spacing | 450 mm centres | Standard residential spacing per NASH Pt 1 |
| Design live load | 1.5 kPa (residential) | 2.0 kPa for balconies; >1.5 kPa requires engineering calculations |
| Concentrated load limit | 1.8 kN max | Loads exceeding 1.8 kN require engineering calculations |
| Deflection limit | Span/500 and 12 mm max | Under service loads per NASH Pt 1 |
| Min. ground clearance | 400 mm | 150 mm localised (within 2 m of ventilated wall) on sloping sites |
| Coastal exclusion zone | >1 km from aggressive environments | ZAM® finish available for adverse/coastal environments |
| Flooring substrate | Particle board or plywood | Min. modulus of elasticity E = 3 GPa; glue and screw recommended |
| Scope | Class 1a dwellings (NCC) | Single occupancy residential; AS4055 Clause 1.2 limitations apply |
Key Technical Facts
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