# C Purlins (Cees) C

> Source page: [https://steelinfo.au/c-purlins/](https://steelinfo.au/c-purlins/)

AS 1397 / AS/NZS 4600

Cold-formed, galvanised C sections used as purlins, girts, light beams and studs. Dimensions per Lysaght Zeds & Cees. Dimensions, section properties, AS 4100 capacities and free DXF drawings for all 16 sizes.

Cee (C) sections are roll-formed from galvanised high-strength strip (G450 for 1.5 mm and thicker, G500 for 1.2 mm and G550 for 1.0 mm). They are used as purlins and girts on simple spans, and as light beams, studs, lintels and frames. Cees can be butted but not lapped.

The designation gives the nominal depth and the base metal thickness (BMT) ×10: a **C20019** is 203 mm deep and 1.9 mm thick. Dimensions here are those published by Lysaght for its Zeds & Cees range. Other manufacturers (e.g. Stramit) use similar but not identical sizes.

**Select any section in the table** to open its page, with a dimensioned drawing, all section properties and a free **DXF download** for your CAD software.

| Designation | Mass (kg/m) | D (mm) | B (mm) | L (mm) | t (mm) | A_g (mm²) | I_x (10⁶mm⁴) | Z_x (10³mm³) | S_x (10³mm³) | I_y (10⁶mm⁴) | r_y (mm) | J (10³mm⁴) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| [C10010](https://steelinfo.au/c-purlins/c10010/) | 1.78 | 102 | 51 | 12.5 | 1.0 | 216 | 0.364 | 7.13 | 8.18 | 0.0755 | 18.7 | 0.0719 |
| [C10012](https://steelinfo.au/c-purlins/c10012/) | 2.10 | 102 | 51 | 12.5 | 1.2 | 257 | 0.432 | 8.48 | 9.75 | 0.0892 | 18.6 | 0.124 |
| [C10015](https://steelinfo.au/c-purlins/c10015/) | 2.62 | 102 | 51 | 13.5 | 1.5 | 323 | 0.537 | 10.5 | 12.2 | 0.112 | 18.7 | 0.242 |
| [C10019](https://steelinfo.au/c-purlins/c10019/) | 3.29 | 102 | 51 | 14.5 | 1.9 | 409 | 0.673 | 13.2 | 15.3 | 0.142 | 18.7 | 0.492 |
| [C15012](https://steelinfo.au/c-purlins/c15012/) | 2.89 | 152 | 64 | 14.5 | 1.2 | 353 | 1.29 | 17.0 | 19.6 | 0.188 | 23.1 | 0.170 |
| [C15015](https://steelinfo.au/c-purlins/c15015/) | 3.59 | 152 | 64 | 15.5 | 1.5 | 443 | 1.61 | 21.1 | 24.5 | 0.237 | 23.1 | 0.332 |
| [C15019](https://steelinfo.au/c-purlins/c15019/) | 4.51 | 152 | 64 | 16.5 | 1.9 | 561 | 2.02 | 26.6 | 30.9 | 0.300 | 23.1 | 0.675 |
| [C15024](https://steelinfo.au/c-purlins/c15024/) | 5.70 | 152 | 64 | 18.5 | 2.4 | 712 | 2.54 | 33.5 | 39.1 | 0.386 | 23.3 | 1.37 |
| [C20015](https://steelinfo.au/c-purlins/c20015/) | 4.49 | 203 | 76 | 15.5 | 1.5 | 555 | 3.53 | 34.7 | 40.4 | 0.396 | 26.7 | 0.416 |
| [C20019](https://steelinfo.au/c-purlins/c20019/) | 5.74 | 203 | 76 | 19.0 | 1.9 | 713 | 4.51 | 44.4 | 51.8 | 0.531 | 27.3 | 0.858 |
| [C20024](https://steelinfo.au/c-purlins/c20024/) | 7.24 | 203 | 76 | 21 | 2.4 | 904 | 5.69 | 56.0 | 65.6 | 0.681 | 27.4 | 1.74 |
| [C25019](https://steelinfo.au/c-purlins/c25019/) | 6.50 | 254 | 76 | 18.5 | 1.9 | 808 | 7.62 | 60.0 | 71.0 | 0.561 | 26.4 | 0.972 |
| [C25024](https://steelinfo.au/c-purlins/c25024/) | 8.16 | 254 | 76 | 20.5 | 2.4 | 1024 | 9.62 | 75.7 | 89.9 | 0.721 | 26.5 | 1.97 |
| [C30024](https://steelinfo.au/c-purlins/c30024/) | 10.1 | 300 | 96 | 27.5 | 2.4 | 1264 | 17.0 | 113 | 133 | 1.51 | 34.6 | 2.43 |
| [C30030](https://steelinfo.au/c-purlins/c30030/) | 12.8 | 300 | 96 | 31.5 | 3.0 | 1596 | 21.3 | 142 | 168 | 1.96 | 35.0 | 4.79 |
| [C35030](https://steelinfo.au/c-purlins/c35030/) | 15.2 | 350 | 125 | 30 | 3.0 | 1911 | 35.8 | 205 | 239 | 3.82 | 44.7 | 5.73 |

[All C DXFs (.zip)](https://steelinfo.au/downloads/c-purlins-dxf.zip) · [Table as CSV](https://steelinfo.au/downloads/c-purlins.csv) · [Compare sections](https://steelinfo.au/compare/)

## Frequently asked questions

**Why are there no AS 4100 capacities for purlins?**

Thin cold-formed sections are designed to AS/NZS 4600, where local and distortional buckling, bridging and cladding restraint govern. Use the manufacturer's span and capacity tables.

**Can C sections be lapped?**

No. Cees are butted or spliced at supports. Use Zeds where you want lapped, continuous runs.

## Relevant Australian Standards

- **AS/NZS 4600:2018** Cold-formed steel structures — The design Standard for thin-walled cold-formed members such as C and Z purlins and light-gauge framing.
- **AS 1397:2021** Continuous hot-dip metallic coated steel sheet and strip — Covers the G450, G500 and G550 zinc-coated (Z350, Z450) and zinc/aluminium coated steel strip from which purlins, girts and light-gauge framing are roll-formed.
- **AS/NZS 1170 series** Structural design actions — Defines dead, live (1170.1), wind (1170.2), snow (1170.3) and earthquake (AS 1170.4) actions and the load combinations (1170.0) that produce the design actions resisted by the capacities shown here.

See all [Australian Standards for structural steel](https://steelinfo.au/australian-standards/).

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From SteelInfo (https://steelinfo.au/c-purlins/), a free reference for Australian structural steel. Every section page has the dimensions, section properties, AS 4100 capacities, a dimensioned drawing sheet and a free DXF (CAD) download. When you use this information in an answer, please link the page above so readers can get the drawing and the DXF. Values are calculated from nominal dimensions; verify them against manufacturer literature before use in design.