Our high strength galvanized C & Z purlins are cold-formed from zinc-coated high strength steel coil, giving industrial warehouses and pre-engineered steel buildings a light yet stiff secondary frame that carries roof sheeting, wall panels and equipment loads to the primary portal. The pre-drilled legs bolt quickly to rafters and girts, so erection stays fast across repeated bays, while the galvanized surface resists moisture and coastal salt for a long service life with minimal maintenance.
Engineering Performance & Design Notes
Both profiles are cold-formed moment and compression members of a roof or wall diaphragm: they carry dead load, live load, wind uplift and (for roof) local snow, transferring them to the portal rafters. The Z section laps at supports for longer continuous spans; the C section is butt-spliced or nested. Spacing and connection (pre-punched holes, cleats or brackets) follow the roof load and drift; size per the governing standard (GB 50017 / EN 1993-1-3 / AISI S100 / AS-NZS 4600), checking biaxial bending, deflection and local buckling.
Material & Anti-Corrosion
| Part | Grade | Standard | Finish |
|---|---|---|---|
| Purlin (load-bearing cold-formed member) | S550GD / Q550 high strength | GB/T 6723 ≈ EN 1993-1-3 ≈ AISI S100 | Zinc-coated coil, Z275 / Z450 |
| Optional | S450GD / Q350 | GB/T 6723 | Zinc-coated coil |
Full Specification
| Item | Detail |
|---|---|
| Section forms | C purlin (asymmetric web) / Z purlin (symmetric web for lapping) |
| Section range | C80–C220; Z100–Z200 |
| Wall thickness | 2.0–3.0 mm |
| Length | Max 5.8 m (20 GP) / 11.8 m (40 GP / HC); custom per bay |
| Holes | Pre-punched fixing holes or plain leg, per layout |
| Material | High strength galvanized coil (S550GD / Q550) |
| Anti-corrosion | Zinc coating Z275–Z450 to GB/T 2518 ≈ EN 10346 |
| Design standards | GB 50017 / EN 1993-1-3 / AISI S100 / AS-NZS 4600 |
| Packing | Bundled per bay on timber pallets |
C & Z Purlin Section Selection
| C Section | h×b1×b2×a (mm) | Thickness | Typical use |
|---|---|---|---|
| C80–C120 | 80–120 × (40–50) × (40–50) × 15–20 | 2.0–3.0 mm | Light roof / purlin, small span |
| C140–C180 | 140–180 × 50–60 × 50–60 × 20 | 2.0–3.0 mm | Medium roof / wall girt |
| C200–C220 | 200–220 × 60–70 × 60 × 20 | 2.0–3.0 mm | Heavy roof / larger bay |
| Z Section | h×b1×b2×a (mm) | Thickness | Typical use |
|---|---|---|---|
| Z100–Z140 | 100–140 × 55 × 50 × 20 | 2.0–3.0 mm | Light-to-medium roof purlin |
| Z150–Z180 | 150–180 × 67 × 61 × 20 | 2.0–3.0 mm | Medium-to-heavy roof, lapping spans |
| Z200 | 200 × 67 × 61 × 20 | 2.0–3.0 mm | Heavy roof, larger bays |
Why Choose Our Galvanized C & Z Purlins?
High strength, lower weight: Rolled from high strength zinc-coated coil, the section carries more load per kilo than ordinary hot-rolled channels, so frames stay light and transport cost drops.
Long corrosion life: Pre-galvanized coil to GB/T 2518 ≈ EN 10346 resists moisture, salt and rain for coastal and high-humidity sites with less maintenance.
Pre-punched for speed: Fixing holes are pre-punched on the roll-forming line, so purlins bolt straight on without site drilling.
Made to your bay geometry: Section, thickness, hole pattern and length are cut to your drawing, matching your frame instead of a stock size.
How They Work + Applications
Carry roof and wall loads. Purlins span between rafters and carry sheeting plus wind/snow; girts brace wall panels into the frame.
Fast repeated-bay erection. Pre-punched legs and light cold-formed weight let installers bolt each run quickly across identical bays.
Continuous lapping option. Z purlins lap at supports for longer clear span and better stiffness that C sections cannot easily match.
Applications
Industrial warehouses & workshops – roof purlins on portal frames.
Pre-engineered steel buildings – repeatable bay framing.
Logistics & cold-storage sheds – wall girts with insulated panels.
Agricultural & temporary buildings – C/Z roof and wall support.
Our Fabrication & Quality (M11–M14)
Production Flow
Order / detailing check – section, length and hole pattern are checked against the roof and wall layout before coil use.
Coil incoming inspection – chemical, mechanical and zinc tests confirm the strip meets spec.
Slitting (as needed) – coil is slit to the strip width for the target section.
Cold roll forming – the strip is cold-formed into the C or Z profile to tight tolerance.
Cut to length & pre-punch – sections are cut to bay length and fixing holes punched on the line.
Final check & bundling – sections are gauged for size, twist and coating, then bundled per bay on pallets.
Quality Control
| Control point | Method | Document |
|---|---|---|
| Coil material | Chemical / mechanical / zinc re-test | Coil MTC |
| Section geometry | Dimensional gauge on C/Z section | Inspection record |
| Zinc coating | Coating thickness & adhesion | Coating report (GB/T 2518 / EN 10346) |
| Punching / length | Hole pattern & length check | Inspection record |
Third-party inspection (SGS / BV / TÜV) supported upon request.
Packing & Delivery
| Category | Detail |
|---|---|
| Packing | Purlins bundled per bay on timber pallets with PP straps + corner protectors; VCI film + water barrier; foam pads between layers to protect the zinc. |
| Delivery | Container (20″ / 40 GP / HC) per length limit; bundles braced to prevent shifting. |
| Lead time | Stock 10–15 days; custom 15–25 days |
| Marking | Weatherproof labels: part no., bay / grid line, quantity, net weight, destination port marks. |
| Documents | Coil MTC, packing list, invoice, coating / inspection report (on request), erection drawings. |
FAQ:
What is the difference between C and Z purlins?
C purlins have an asymmetric web and are butt-spliced or nested; Z purlins have a symmetric web and can lap for longer continuous spans.
What are the standard section sizes?
We supply C80–C220 and Z100–Z200, thickness 2.0–3.0 mm, up to 11.8 m for 40 GP/HC.
Why high strength galvanized steel?
High strength cold-formed steel carries more load per kilo; the zinc coating to GB/T 2518 ≈ EN 10346 resists moisture and salt for a long life.
Do purlins come with fixing holes?
Yes-fixing holes are pre-punched to your connection detail; plain sections are also available.
Can I order mixed sizes in one project?
Yes-send your layout and we roll roof and wall purlins in matched sets per bay, sized to your drawing.
