GALVANIZED C-CHANNELS

Galvanized C-channels — also known as galvanized C profiles, C-purlins or lipped channels — are cold-formed structural profiles that serve as the primary secondary steelwork in steel-framed buildings across Europe. These profiles provide the essential support structure between main portal frames, carrying roof cladding, wall sheeting, insulation and solar panel systems. ULAMEX supplies galvanized C purlins in heights from 100 to 300 mm, manufactured from S350GD+Z275 strip-galvanized steel per EN 10346, with a continuous zinc coating of 275 g/m² for reliable corrosion protection in exposed outdoor applications. As a dedicated galvanized steel channel supplier with extensive European stock, we deliver from warehouse with full documentation and competitive wholesale conditions.

Material Grade and Galvanizing Specification

Cold formed galvanized profiles in our C-channel programme are manufactured exclusively from S350GD+Z275 steel coil per EN 10346. This grade designation encodes the following key properties:

• S350GD — structural steel for cold forming with a minimum yield strength of 350 MPa, tensile strength 420–520 MPa and minimum elongation of 16%. The “GD” suffix indicates a galvanized product suitable for structural applications. This yield strength places the material between S235JR and S355J2 in terms of structural performance, providing an optimised balance of strength, formability and weight efficiency for purlin and girt applications.
• Z275 — indicates a total zinc coating mass of 275 g/m² on both surfaces combined (approximately 137.5 g/m² per side, corresponding to approximately 20 µm zinc layer thickness per side). This zinc coating is applied continuously to the flat steel strip by immersion in molten zinc during the coil manufacturing process, before the strip is cold-formed into the C-profile shape. The Z275 coating class is the standard specification for structural purlins and provides corrosion protection sufficient for a service life of 25–40 years in typical C2–C3 corrosivity environments per EN ISO 9223.

The continuous strip galvanizing process (also called continuous hot-dip coating or Sendzimir galvanizing) produces a thinner but highly uniform zinc coating compared to batch hot-dip galvanizing per EN ISO 1461. The key advantage is consistency — every square centimetre of the profile surface receives exactly the same zinc thickness, including inside corners, lip edges and web surfaces that can be difficult to coat uniformly in batch galvanizing.

Structural Design and Span Capabilities

Galvanized steel purlins in C-profile configuration are designed as secondary structural members spanning between primary portal frame rafters or columns. The achievable span depends on the profile height, thickness, purlin spacing, roof pitch and the applicable load combination (dead load + live load + snow load + wind load) per Eurocode 1 (EN 1991) and structural design per Eurocode 3 (EN 1993):

• C100–C140 profiles — suitable for spans of 3.0–5.5 metres at standard purlin spacings of 1.2–2.0 m. Typical for small canopies, carports, lean-to structures and agricultural buildings with moderate snow loads.
• C160–C200 profiles — the most commonly specified range, covering spans of 5.0–8.0 metres. Standard for industrial hall roofs, warehouse buildings and logistics centres across Central Europe. A C200×70×2.5 purlin at 1.5 m spacing typically handles snow loads up to zone 3 (sk = 1.5 kN/m²) at 6 m span.
• C250–C300 profiles — engineered for longer spans of 7.0–12.0 metres in single-span configuration or longer as continuous (multi-span) systems. Used in wide-span industrial halls, distribution centres and special applications requiring large purlin spacings or heavy roof loads.

For multi-span applications, C-purlins can be installed with sleeve connections at internal supports, creating continuity that increases the effective span capacity by approximately 20–30% compared to simply-supported single spans. Alternatively, overlapping purlin systems (where adjacent purlins are lapped at the support by 10–15% of the span length) achieve similar continuity benefits. For anti-sag systems in long-span roofs, sag rods or sag angles are installed at mid-span or third-points to prevent lateral-torsional instability.

Applications of Galvanized C-Channels

Cold formed galvanized profiles in C-channel configuration serve a wide range of structural and industrial applications:

• Roof purlin systems — the primary application for C-profiles. Purlins span between portal frame rafters at spacings of 1.0–2.5 m, supporting sandwich panels, trapezoidal sheeting, standing seam roofing or photovoltaic mounting rails. The galvanized C purlin is the standard building block of European steel hall construction.
• Wall girt systems — horizontal C-channels spanning between columns, supporting wall cladding panels and providing lateral stability. Wall girts are typically one size smaller than the corresponding roof purlins in the same building, as wall loads (primarily wind) are generally lower than roof loads (snow + wind).
• Canopy and carport structures — galvanized C-purlins form the roof framework of carport constructions, open canopies and covered walkways. The corrosion-resistant zinc coating is essential for these unenclosed structures with full weather exposure.
• Solar and photovoltaic substructures — C-channels serve as horizontal mounting rails in ground-mounted solar arrays, supporting the PV module clamps at the correct tilt angle. The 25–40 year corrosion protection of Z275-coated profiles matches or exceeds the design life of the solar installation.
• Mezzanine and platform construction — C-profiles are used as floor joists and edge beams in lightweight mezzanine floors within warehouses, retail spaces and logistics facilities.
• Agricultural buildings — livestock shelters, hay barns, machinery sheds and greenhouse substructures utilise galvanized steel purlins for their combination of structural performance and corrosion resistance in chemically aggressive agricultural environments.
• Facade and cladding substructures — C-channels mounted horizontally or vertically on the primary structure provide the mounting grid for facade panels, mineral wool insulation systems and ventilated rainscreen cladding.

Technical Properties and Processing

The cold-forming process and strip galvanizing impart specific technical characteristics to galvanized C profile purlins:

• Weldability — S350GD+Z275 C-channels can be welded using MIG/MAG and TIG processes with appropriate zinc-compatible welding wire. The zinc coating burns away in the heat-affected zone and must be restored with zinc-rich primer or spray metallizing after welding. Due to the thin wall sections (1.5–3.0 mm), reduced welding currents and speeds are necessary to avoid burn-through. For most purlin installations, bolted connections using cleats, brackets and self-drilling screws are preferred over welding.
• Bolting and connection — standard purlin connections use purlin cleats (L-shaped brackets) bolted to the primary frame rafter, with the C-purlin bolted to the cleat using M12 or M16 grade 8.8 bolts. This cleat-and-bolt system allows site adjustment, simplifies installation and enables future purlin replacement if needed.
• Drilling and punching — C-profiles can be drilled, punched and notched using standard metalworking equipment. Pre-punched mounting holes for cleat connections and sheeting fixings can be specified at the time of order.
• Cutting — sawing, abrasive cutting or cold cutting with circular saws are preferred cutting methods. Avoid oxy-fuel cutting, which generates excessive heat and destroys the zinc coating over a wide zone. The cathodic protection of the zinc coating protects cut edges from corrosion for a distance of approximately 2–3 mm from the edge.

Quality Assurance and Certification

ULAMEX is EN 1090 certified and operates under an ISO 3834-2 quality management system and ISO 3834 welding quality system. All galvanized C-channels in our stock programme are supplied with:

• CE marking documentation per EN 10346
• Mill test certificates 3.1 per EN 10204 (on request)
• Declaration of Performance (DoP) for Construction Products Regulation compliance
• Full material traceability to production coil, mill and galvanizing line

Frequently Asked Questions — Galvanized C-Channels

What is the difference between C-purlins and Z-purlins?

C-purlins have a symmetrical C-shaped cross-section (web + two flanges turning the same direction + lips). Z-purlins have a Z-shaped cross-section where the flanges extend in opposite directions. The key difference is at multi-span overlaps: Z-purlins can be nested (overlapped) at internal supports because their shape allows one purlin to fit inside the other, creating structural continuity. C-purlins cannot nest and require sleeve connectors for continuity. Both types are available from ULAMEX in galvanized execution.

How do I select the right C-purlin size for my project?

Purlin selection depends on span between rafters, purlin spacing, roof cladding weight, snow load zone, wind load zone and building location altitude. A structural engineer calculates the required section modulus and moment of inertia per Eurocode 3 (EN 1993-1-3 for cold-formed sections). As a general guideline, the purlin height in mm should be approximately 1/30 to 1/25 of the span in mm for single-span applications. Contact ULAMEX for technical guidance on purlin selection.

Can galvanized C-channels be used outdoors without additional coating?

Yes. The Z275 zinc coating (275 g/m², approximately 20 µm per side) provides maintenance-free corrosion protection for 25–40 years in typical C2–C3 outdoor environments per EN ISO 9223. No additional primer, paint or coating is required for standard structural applications. For highly aggressive environments (C4–C5, coastal or chemical-industrial), a duplex coating system (galvanized + paint) can extend the service life further.

What is the minimum order quantity for galvanized C-purlins?

ULAMEX supplies galvanized C-channels to B2B customers from single bundles for stock items. For non-standard dimensions or cut-to-length requirements, minimum order quantities may apply. Request a quote with your project dimensions and quantities for exact availability and pricing.

ULAMEX is your trusted galvanized steel channel partner for purlin systems, wall girts and structural C-profiles. Browse our complete galvanized steel range or explore all galvanized profiles. For project-specific quotations covering galvanized C purlins with delivery across Europe, request a quote today or contact our structural steel team directly.