2″ x 4″ x 20′ C-Purlin 1.2mm~1.5mm

2″ × 4″ × 20′ C-Purlin – 1.2mm–1.5mm

Cold-formed galvanised steel C-purlin measuring 2 inches × 4 inches × 20 feet with a wall thickness of 1.2mm–1.5mm — designed for use as roof purlins, wall girts, and structural framing members in residential, commercial, and industrial construction applications.

Key Benefits

• 2″ × 4″ section for medium-span structural applications
• 20-foot length for efficient roof and wall bay spacing
• 1.2mm–1.5mm wall thickness for structural integrity
• Galvanised steel for corrosion resistance
• Lightweight compared to equivalent hot-rolled sections
• C-profile for efficient structural depth-to-weight ratio
• Suitable for roofing, wall girts, and general framing
• Compatible with standard purlin bridging and cleats
• Cut to length on site as required
• Cost-effective structural framing solution

Technical Specifications

• Profile: C-Purlin (C-section)
• Flange Width: 2 inches
• Web Depth: 4 inches
• Length: 20 feet
• Wall Thickness: 1.2mm – 1.5mm
• Material: Cold-formed galvanised steel
• Finish: Galvanised (zinc coated)
• Application: Roof purlins, wall girts, structural framing

Features

• Cold-formed C-section profile provides structural efficiency — the channel shape resists bending loads across the web depth
• Galvanised zinc coating protects against corrosion in exposed roofing and outdoor framing applications
• 20-foot length spans standard building bay spacings with minimal waste
• 1.2mm–1.5mm wall thickness provides adequate load capacity for typical residential and light commercial purlin spacing
• Lightweight construction simplifies handling, cutting, and installation compared to hot-rolled steel sections
• Punched or slotted fixing holes at standard intervals allow direct connection to rafters, portal frames, and wall columns
• Compatible with standard purlin bridging, anti-sag systems, and cleat connections

Perfect For

• Roof purlin installation on steel-framed buildings
• Wall girt framing on industrial and commercial structures
• Residential steel roof framing
• Warehouse and shed construction
• Agricultural building framing
• Secondary structural framing on portal frame buildings
• Mezzanine and floor framing support
• General light structural steel framing
• Canopy and carport construction
• Retrofit roof framing over existing structures

Key Features

• C-Section Profile: The C (channel) shape provides a favourable structural depth in the 4-inch web direction, enabling it to span between rafters or columns with efficient material use relative to flat or angle sections
• 2″ × 4″ Dimensions: The 4-inch web depth provides structural bending capacity while the 2-inch flanges provide flange stability and fixing area at the support points
• 20-Foot Length: Standard 20-foot lengths align with common building bay spacings, reducing the number of joints and laps required in typical construction
• 1.2mm–1.5mm Wall Thickness: Appropriate for light to medium residential and commercial purlin loading — for heavier spans or loading conditions, consult a structural engineer for specification
• Galvanised Finish: Zinc galvanising protects the steel from rust and corrosion in roofing and outdoor applications, extending service life compared to uncoated steel
• Cold-Formed Construction: Roll-formed from galvanised coil steel, producing a consistent section profile with tight dimensional tolerances throughout the length

Application Instructions

1. Confirm purlin spacing and span requirements with a structural engineer or to the relevant building code before installation
2. Ensure the supporting structure (rafters, portal frames, or wall columns) is correctly positioned and level before installing purlins
3. Cut purlins to length on site as required using a metal cutting saw or angle grinder with a metal cutting disc
4. Position the purlin with the web vertical and the flanges facing the correct direction for the fixing method being used
5. Secure purlins to the supporting structure using appropriate cleat connections, bolts, or self-drilling screws at each support point
6. Install purlin bridging or anti-sag rods at mid-span where required to prevent lateral buckling
7. Lap purlin lengths at support points where continuous runs exceed the single length — overlap to the manufacturer’s or engineer’s specification
8. Apply touch-up galvanising compound to any cut ends or damaged coating areas before covering
9. Do not modify the section by notching, drilling large holes, or welding without engineering assessment
10. Ensure all connections comply with the relevant local building code requirements

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