Structural Steel Material

C/Z Purlin — Cold-Formed Galvanized Steel Purlins

High-strength cold-formed steel purlins and girts for secondary framing of metal building roofs and walls. Available in C, Z, and Sigma profiles with various zinc coatings, pre-punched holes, and custom lengths up to 12 meters.

Technical Specifications

Parameter	Specification
Steel Grade	Q235B, Q345B, S280GD+Z, S350GD+Z, S550GD+Z
Section Type	C purlin (lipped channel), Z purlin (lipped Z), Sigma purlin
Web Height	80mm, 100mm, 120mm, 140mm, 160mm, 180mm, 200mm, 250mm, 300mm
Flange Width	40mm - 80mm (standard 50mm, 60mm, 65mm)
Thickness	1.5mm, 1.8mm, 2.0mm, 2.3mm, 2.5mm, 3.0mm
Zinc Coating	Z60 (60g/m²), Z100 (100g/m²), Z180 (180g/m²), Z275 (275g/m²)
Length	Up to 12m standard; custom lengths available
Pre-punched Holes	Bolt holes per design, slotted holes for adjustment
Standard	GB/T 6728, EN 10162, ASTM A653

Applications

Roof Purlins

Secondary framing supporting roof sheeting and insulation. Z purlins preferred for roof slopes over 15° for better lap connection.

Wall Girts

Horizontal wall framing members supporting wall cladding. C purlins commonly used for wall applications.

Mezzanine Floors

Floor joists for mezzanine levels in warehouses and factories, supporting floor decking and live loads.

Solar Panel Mounting

Support structures for rooftop solar panel installations, corrosion-resistant galvanized finish.

Features & Options

C vs Z Selection — C purlins for walls and low-slope roofs; Z purlins for steeper roofs (overlapping flanges provide stronger continuous span)
High-Strength Steel — S550GD+Z high-strength galvanized steel reduces thickness and weight while maintaining load capacity
Pre-punched Holes — Bolt holes pre-punched at factory for faster on-site assembly, slotted holes for thermal expansion adjustment
Anti-sag Rods — Compatible with anti-sag rod systems for long purlin spans, preventing lateral deflection
Color Coated Option — Pre-painted galvanized purlins available in RAL colors for exposed architectural applications

Packing & Delivery

Bundle Packing — Purlins bundled in 2-3 ton bundles with steel strapping, plastic separators to prevent scratching
Container Loading — 40HQ container loads 20-25 tons of purlins; nested stacking maximizes space utilization
End Protection — Plastic caps on cut ends to prevent moisture ingress and corrosion during transit
Documentation — Packing list with piece marks, zinc coating test report, mill certificate

Frequently Asked Questions

Q: What is the difference between C and Z purlins?

A: C purlins have parallel flanges, ideal for walls and low-slope roofs. Z purlins have overlapping flanges that create a continuous beam effect, offering 20-30% higher load capacity for roof slopes over 15°. Z purlins are typically more cost-effective for long-span roofs.

Q: What zinc coating is recommended for coastal areas?

A: For coastal or high-humidity environments, Z275 (275g/m²) minimum is recommended. For severe corrosion environments (salt spray, chemical exposure), consider Z350 or pre-painted purlins with additional corrosion protection.

Q: Can purlins be spliced for longer spans?

A: Yes, Z purlins are designed for lapped splices (typically 400-600mm overlap) to achieve continuous spans. C purlins require bolted splice plates. Maximum single length is 12m due to transport constraints; longer spans use spliced sections.

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