Secondary framing package

Scope of supply

Secondary framing transfers roof and wall loads from the cladding to the rigid frames and stabilises the frame flanges. World Steel roll-forms these members from galvanized coil, cuts them to length and punches every hole on the line, so that the package bolts up to the primary frames without site drilling. It is sold under the secondary members product line.

• Z and C purlins, simple-span or lapped over the frames for continuity.
• Girts for side and endwalls, flush or bypass.
• Eave struts at the eave line.
• Flange braces from purlins and girts to the inner frame flange.
• Rod, cable or angle bracing and portal bracing.
• Sag rods or bridging, purlin bolts, base angles and cladding support angles.

Options and variants

Section depth and thickness are selected by design for each bay, so a building may use several gauges of the same section. Lapped Z purlins are used where continuity reduces weight; simple-span C sections are used at ends and openings. Options include heavier gauges for collateral loads such as solar panels or ceilings, purlin restraint systems for standing seam roofs, and galvanized or painted bracing rods.

Materials and finishes

Typical depths are 150–300 mm with base metal thickness of about 1.5–3.0 mm. Galvanized coil is the standard finish; where a cut edge or punched hole may corrode in a severe environment, a heavier coating mass is recommended. See cold-formed steel.

Compliance by market

Sections, sizes and bracing components

For standing seam roofs, additional purlin restraint – anti-roll clips, bridging lines or diaphragm bracing – is included because the floating roof provides little lateral support. See cold-formed steel and bracing systems.

Documentation, packing and quotation

Deliverables include purlin and girt layouts, member schedules with lengths and hole patterns, design calculations, coil mill certificates and erection drawings. Members are nested in strapped bundles of the same mark, with timber spacers, and loaded in containers alongside the primary frames.

A quotation can be prepared quickly when the enquiry states the project location and the code to be used. Please send:

1. Frame spacing, roof slope and wall heights, or the primary frame drawings.
2. Cladding type and its span and fixing requirements.
3. Design loads including wind, snow and collateral loads.
4. Required coating mass and site environment.

World Steel returns a priced scope with a clear inclusions and exclusions list, the design basis assumed and a typical lead time. Enquiries go through the export supply team in Ho Chi Minh City.