Cold Formed Steel Purlins: Complete Guide 2026
Everything you need to know about C-purlins, Z-purlins, sizing, load capacity, and sourcing for metal building construction in Texas.
What Are Cold Formed Steel Purlins?
Cold formed steel purlins are horizontal structural members that span between primary building frames to support roof and wall panels. They're manufactured by roll-forming sheet steel at room temperature into C or Z shapes.
C-Purlins vs Z-Purlins
C-Purlins: C-shaped cross-section with flanges on same side. Best for simple spans and wall girts.
Z-Purlins: Z-shaped with offset flanges. Superior for continuous spans and roof applications due to nesting capability.
Standard Sizes and Load Capacities
Common C-Purlin Sizes
- 8" depth: 8x2.5, 8x2.75 (light-duty applications)
- 10" depth: 10x2.5, 10x2.75 (standard roofing)
- 12" depth: 12x2.5, 12x3.0 (heavy loads, long spans)
Common Z-Purlin Sizes
- 8" depth: 8x2.5 (wall girts, light roofs)
- 10" depth: 10x2.5, 10x2.75 (standard applications)
- 12" depth: 12x2.5, 12x3.0 (heavy roofing, wide spans)
Material Specifications
Steel Grade: ASTM A653 Grade 50 (50 ksi yield strength)
Coating: G90 galvanized (0.90 oz zinc per sq ft) for corrosion resistance
Thickness: 14-18 gauge (0.0747" to 0.0478")
Pricing and Availability
2026 Texas Pricing: $2.50-$4.50 per linear foot depending on size and gauge
Delivery: Stock lengths 20', 24', 30', 40'. Custom lengths available.
Applications in Metal Buildings
- Roof purlins for metal panel support
- Wall girts for siding attachment
- Eave struts and rake purlins
- Bypass girts for openings
Source Quality Steel Purlins in West Texas
Affinity Steel stocks C-purlins and Z-purlins in all standard sizes with same-day pickup and delivery throughout the Permian Basin.
Was this article helpful?
Your feedback helps us improve our content.
Keep Reading
More from our blog on steel, roofing, and metal building expertise.
Need expert guidance on your project?
Talk to our team about steel buildings, roofing, fabrication, or contractor pricing — serving Midland, Odessa & the Permian Basin.