C and Z roof purlins are cold-formed structural steel members engineered to support roof sheets and wall cladding in steel-framed buildings. Manufactured with a galvanized finish for superior corrosion resistance, these lightweight yet high-strength sections deliver excellent load-bearing capacity across long spans. Widely used in warehouses, factories, workshops, agricultural buildings, and commercial steel structures, C and Z purlins offer a durable, cost-efficient secondary framing solution for modern construction projects requiring reliable roof and wall support systems.
Diagram Specification
The structural diagram illustrates the two most common cold-formed purlin profiles used in secondary roof and wall framing: the C-section and the Z-section.
The C Section forms a simple channel shape with a web, two parallel flanges, and inward-turned lips at each end. This symmetrical profile is easy to install, connects cleanly to structural frames, and is commonly used where purlins do not need to overlap.
The Z Section features flanges that turn in opposite directions, creating an offset "Z" shape. This asymmetrical design allows adjacent purlins to overlap or "sleeve" at supports, increasing continuity and load capacity across longer spans — making it a preferred choice for larger structures.
Key dimensional elements shown in the diagram include:
Frequently Asked Questions
