Modelling, load paths and detailing for cold-formed steel frames. In this article we walk through what we have learned on real projects, with numbers you can use.
Why it matters
Cold-formed steel (CFS) framing rewards preparation. Every stud, track and nog is cut, punched and labelled by a machine, so a decision made in the model shows up on site exactly as drawn — good or bad. Getting the inputs right is the cheapest quality control you will ever buy.
Teams that treat the model as the single source of truth typically cut on-site rework by more than half and finish framing in days rather than weeks.
The checklist
Geometry
- All walls are closed polylines with consistent thickness.
- Openings are real voids, not just symbols on a drawing.
- Levels and datums are named and match the structural drawings.
Profiles and gauge
- One profile family per element type (C89, C140, U-track).
- Gauge assigned per wall, not guessed by the detailer.
- Lip and web sizes match the tooling on your machine.
Connections
- Pick a connection rule per junction: L, T and X.
- Confirm screw and bolt hole positions with the fabricator.
- Export a test panel before releasing the whole job.
Typical section sizes
The table below lists the profiles we see most often on two-storey residential work. Always confirm with your engineer — loads, spans and local codes vary.
| Element | Profile | Gauge (mm) | Max spacing | Notes |
|---|---|---|---|---|
| Load-bearing wall | C89 × 41 | 0.95 | 600 mm | Single storey above |
| Load-bearing wall | C89 × 41 | 1.15 | 400 mm | Two storeys above |
| Partition | C70 × 35 | 0.75 | 600 mm | Non-structural |
| Floor joist | C200 × 50 | 1.55 | 450 mm | Spans up to 4.2 m |
| Roof truss chord | C89 × 41 | 0.95 | 1200 mm | Webbed truss |
Common mistakes
Mixing units
A model drawn in centimetres and exported as millimetres produces frames ten times too small. Check the export settings every time.
Ignoring services
Plumbing and electrical runs need pre-punched holes in the right place. Add them to the model, not with a drill on site.
Skipping the test panel
Form one panel and dry-fit it. Ten minutes of checking saves a day of re-forming.
What to do next
Start small: pick one wall type, run it end to end, and measure the time it takes. Once the team trusts the output, scale up to a full house. If you want a second pair of eyes on your model, upload it to LGSF Market and our engineers will review it.
