Key takeaways
- Profile choice is driven by minimum roof pitch, span and local market convention, not by aesthetics alone.
- Corrugated (762 mm, 12 waves) remains the standard in the UK, Australia and much of Africa; IBR and trapezoidal dominate elsewhere.
- Only standing seam is a concealed-fix, mechanically seamed system suitable for pitches down to 1–3°.
- Thickness range for all roofing profiles is broadly 0.3–0.8 mm; heavier material is used where spans are longer or wind loads higher.
The five profile families
Almost all metal roofing sits in one of five families. Corrugated is the traditional sinusoidal wave. Trapezoidal uses angular ribs with flat pans between them. IBR — inverted box rib — is a trapezoidal variant with a boxed rib that is common in South Africa, Australia and the UK. Standing seam is a concealed-fix profile with a raised seam that is mechanically folded or snapped closed. Tile-effect reproduces the appearance of clay or concrete tiles.
The profile is not cosmetic. It sets the minimum roof pitch, because pitch tolerance comes from the height and shape of the side lap; it sets the achievable span between purlins, because it comes from the depth and stiffening of the ribs; and it sets which market you can sell into, because buyers in different countries specify by local convention.
| Profile | Typical cover width | Min. pitch | Fixing | Main markets |
|---|---|---|---|---|
| Corrugated | 762 / 900 / 1000 mm | 10–15° (varies) | Through-fix | UK, Ireland, Australia, Africa, SE Asia |
| Trapezoidal | 900 / 1000 / 1070 mm | 5–10° | Through-fix | Europe, Middle East, Asia, Latin America |
| IBR | 686 / 890 mm | 5–10° | Through-fix | South Africa, Australia, UK |
| Standing seam | 333 / 400 / 430 / 500 mm | 1–3° | Concealed, seamed | Europe, North America, architectural work |
| Tile-effect | 828 / 1050 mm | 15–17° | Through-fix on the rib | Residential markets worldwide |
Why minimum pitch matters more than most buyers expect
The minimum pitch of a roofing profile is set by how well its side lap and end lap resist capillary action and wind-driven rain. A high rib with a well-formed lap tolerates a low pitch; a shallow corrugation does not.
This is why substituting one profile for another on a low-pitch roof is dangerous. A corrugated sheet rated to 10° installed on a 4° roof will leak, not because the sheet is faulty but because the lap geometry cannot shed water at that pitch. Standing seam, which is mechanically seamed rather than lapped, is the only family that reliably goes down to 1–3°.
If you are selecting a machine rather than a roof, this is the single most useful question to ask your market: what pitch are roofs actually built at here? That answer narrows the profile family faster than any other.
Thickness and steel grade
Practically all metal roofing is formed from 0.3–0.8 mm coil. Thin material — 0.3–0.45 mm — suits short spans and markets where cost dominates. Thicker material at 0.5–0.8 mm is used for longer spans, higher wind load areas and where the roof has to resist foot traffic during installation.
Grade matters as much as thickness. Most roofing uses steel between 250 and 350 MPa yield. High-strength G550 allows a thinner sheet for the same strength but is less tolerant of over-forming, so the machine's tooling has to be set up for it. Running high-tensile coil through tooling set for mild steel is a common cause of cracked coatings and distorted ribs.
Coating is the third variable: galvanised, Zincalume (aluminium-zinc), or pre-painted with PE, PVDF or HDP paint systems. PVDF holds colour best in high-UV environments; PE is the cheapest and fades fastest.