Trimdek roofing profile
Trimdek is Lysaght's 29 mm low-rib pierce-fix steel roofing profile: 762 mm cover, 2 degree minimum pitch. The contemporary default for new AU metal roofs.
Ask Chalkline about this →Trimdek is Lysaght’s low-rib, square-fluted steel roofing and walling profile, the volume pierce-fix profile on contemporary Australian residential and light-commercial roofs. The sheet has 29 mm ribs at 187 mm centres and a 762 mm effective cover width. Each rib is pierce-fixed to the supports with hex-head screws and EPDM washers (verified 2026-05-16, Lysaght Trimdek brochure).
Specifications
| Item | Value |
|---|---|
| Rib height | 29 mm |
| Cover width | 762 mm |
| Minimum pitch | 2 degrees (1 in 30) |
| Base metal thickness (BMT) | 0.42 mm and 0.48 mm |
| Anti-capillary groove | Yes (at side lap) |
| Fixing | Pierce-fix to crests with hex screw + EPDM washer |
The anti-capillary groove at the side lap is what allows Trimdek to sit at 2 degrees; the groove breaks the capillary path that would otherwise wick water uphill against gravity.
Why it’s the contemporary default
Trimdek has largely displaced Custom Orb for new builds since the early 2000s:
- Contemporary aesthetic: subtle square ribs rather than the corrugated curve of Custom Orb.
- Lower minimum pitch (2 degrees vs ~5 degrees for Custom Orb).
- Easier flashing details: square profile lines up cleanly with parapet caps, valley irons, and box gutters.
- Faster install: wider cover than Custom Orb means fewer sheets per m².
Equivalent profiles by other brands
The same low-rib square-flute concept under different brand names:
- Stratco CGI and Stratco Spandek: similar rib height and cover, sold by Stratco.
- Metroll Trimsheet: Metroll’s equivalent profile.
- Bluescope Steel Selectors: any rebadged Lysaght-spec product.
The geometry is similar but accessories (clips, flashings, sealers) are typically brand-specific. Mixing brands across a roof is workable but increases install complexity.
On-site checks
- Fasteners driven at every rib that crosses a support (no missed crests).
- EPDM washer compressed to just below the bend in the screw flange. Over-driven causes the washer to tear; under-driven leaks.
- Side laps with the upper sheet riding over the anti-capillary groove of the lower sheet (correct orientation).
- Swarf, drillings, and offcuts swept off the sheet at end of day. Iron particles will rust through the COLORBOND finish.
Also known as: TRIMDEK, Lysaght Trimdek, Stratco CGI (equivalent), Metroll Trimsheet (equivalent).
Category: Metal roofing / cladding profiles.
Related
See also
Last updated: 2026-05-16. Verified: 2026-05-16.