Key takeaways

  • Profile selection comes before machine selection — the profile determines the machine type and tooling required.
  • IBR is a specific geometry, not a generic trapezoidal option — tooling must match the IBR specification.
  • Standing seam is the only profiled metal roofing suitable for slopes below about 5 degrees.
  • Sandwich panel production requires a completely different process from roll forming — not a roofing machine.
  • Regional standards (EN 508-1, AS 1562.1, SABS 1273) govern dimensional tolerances — confirm which applies before ordering tooling.

Why profile selection matters before machine selection

Choosing a metal roofing profile is not a cosmetic decision — the profile geometry determines water performance at low slopes, wind uplift resistance, spanning capability between purlins, and the machine required to produce it. Selecting the profile first, and the machine second, avoids the common mistake of buying a machine for the wrong market or the wrong load case.

The global roofing market uses roughly six profile families. Each has a different geometry, different primary markets, and different performance characteristics. Understanding which family your buyers specify — and which standards govern them — is the starting point for machine selection.

The six main profile families

Trapezoidal profiles use flat pans separated by trapezoidal ribs. They are the most widely used profile globally — common in Europe, the Middle East, Russia, India and much of Asia. Rib pitch is typically 200–333 mm; cover widths are 750–1000 mm. The profile is simple to produce and the machine is relatively low cost.

Corrugated (sine-wave) profiles have a rounded wave form rather than a flat pan. They are used extensively in the UK, Ireland, Australia, New Zealand and parts of Africa. The wave is aesthetically softer than trapezoidal, and the profile performs well in wind and rain. Tooling is specific — a corrugated die cannot produce a trapezoidal shape.

IBR (inverted box rib) is a distinct profile with a specific rib geometry used in South Africa, the rest of Africa, the UK and Australia. Buyers in these markets specify IBR by name — it is not interchangeable with a generic trapezoidal profile even if the dimensions look similar. Tooling must match the IBR specification exactly.

Standing seam panels have tall concealed ribs and are fixed without face penetrations. Specified for high-specification commercial, industrial and architectural applications globally. Require a more complex machine and separate on-site seaming equipment.

Glazed tile / stone-coated profiles simulate the appearance of ceramic or clay roof tiles. Popular in markets where traditional tile aesthetics are expected — parts of Asia, the Middle East and Latin America. The forming process includes embossing and pressing steps beyond standard roll forming.

Sandwich panels combine an outer steel face, a foam or mineral wool core and an inner steel face in a single production line. The production process is completely different from roll forming — it involves lamination and hot or cold forming — and requires a dedicated sandwich panel line, not a standard roll forming machine.

Profile familyPrimary marketsKey characteristicMachine note
TrapezoidalEurope, Middle East, Asia, IndiaFlat pan, trapezoidal ribStandard roofing machine
Corrugated (sine-wave)UK, Ireland, Australia, AfricaRound wave formSpecific corrugating die
IBR (inverted box rib)South Africa, Africa, UK, AustraliaSpecific rib geometryTooling must match IBR spec
Standing seamGlobal, high-specConcealed fix, tall ribComplex tooling, seamer required
Glazed / stone-coated tileAsia, Middle East, Latin AmericaTile appearanceEmbossing/pressing steps
Sandwich panelIndustrial, cold store, food processingComposite wall/roof elementDedicated panel line, not roll forming

Performance characteristics that drive profile choice

Minimum slope is a critical selection factor. Corrugated and trapezoidal profiles require a minimum slope of about 5–8 degrees to drain reliably. Standing seam can be installed at 1.5 degrees or less because there is no fastener lap that water must drain past. If the buyer's building has a low-pitch or near-flat roof, standing seam is the only profiled metal option.

Wind uplift resistance is governed by the profile depth, the rib spacing and the fixing pattern. Deeper, closer-spaced ribs with more fixings per unit area resist higher uplift. In cyclone and hurricane zones, the fixing specification often drives the profile and gauge choice regardless of other factors.

Thermal performance is affected by the profile indirectly — a deeper rib creates a larger air gap above the insulation when cold-room or acoustic insulation is fitted over the purlins. For heavily insulated roofs, a taller rib profile may be specified to create space for insulation without compressing it.

Regional standard requirements

Profile geometry is often governed by regional standards that specify dimensional tolerances, mechanical properties and sometimes aesthetics. EN 508-1 covers profiled steel sheet for roofing in Europe; AS 1562.1 governs in Australia; SABS 1273 is the South African standard for IBR.

A machine and tooling set designed to produce sections that meet EN 508-1 will not necessarily produce sections that comply with SABS 1273, even for nominally similar profiles. If you are entering a regulated market, confirm which standard applies and that the tooling is designed to meet it.

Selecting the machine based on profile and market

Once the profile family and target market are established, machine selection follows: (1) confirm whether the profile requires standard trapezoidal tooling, a corrugated die, IBR-specific tooling, or a standing seam profile; (2) establish the cover width, rib pitch and thickness range that the tooling must cover; (3) determine the production volume and required line speed; (4) decide whether multiple profiles must be produced from one machine (requiring roll cassette changes).

A common mistake is buying a 'multi-profile' machine without specifying which profiles it must switch between. A machine that can switch between two trapezoidal profiles is a simple setup change. A machine that must switch between a trapezoidal and a corrugated profile requires a dedicated cassette for each, which significantly changes the machine cost and changeover time.

Frequently asked questions

What is the most common metal roofing profile?
Trapezoidal profiles are the most widely used globally, covering most of Europe, the Middle East, Russia, India and large parts of Asia. Corrugated (sine-wave) profiles are dominant in the UK, Ireland, Australia and parts of Africa. IBR is the standard in South Africa and most of sub-Saharan Africa. No single profile is universal — selection depends on the target market.
What is IBR roofing?
IBR stands for inverted box rib. It is a specific roof sheet profile with a defined rib geometry used in South Africa, the rest of Africa, the UK, Ireland and Australia. Buyers in these markets specify IBR by name because the rib geometry — particularly the rib width, height and return — is standardised and cannot be substituted with a generic trapezoidal profile. A roll forming machine for IBR must use tooling designed specifically for the IBR profile.
Can one machine produce multiple roofing profiles?
Yes, by changing roll cassettes. A machine with a cassette-change system can switch between trapezoidal, IBR, corrugated and other profiles by exchanging the forming roll set. Changeover takes approximately 2–4 hours. The machine frame, drive and control remain the same; only the rolls change. Confirm the cassette system is included when specifying the machine — it is not always standard.
What is the minimum roof slope for metal roofing?
Standard exposed-fastener profiles (trapezoidal, corrugated, IBR) require a minimum slope of approximately 5 degrees to drain reliably and to seal at the panel lap joints. Standing seam profiles can be installed at 1.5 degrees or less because the seamed joint is fully weatherproof at any angle. For slopes below 5 degrees, standing seam is the correct choice.
What thickness material is used for metal roofing?
Residential and light commercial roofing is typically 0.4–0.6 mm BMT (base metal thickness) in galvanised or pre-painted steel. Heavy commercial and industrial is 0.6–0.9 mm. Structural standing seam can use up to 0.9 mm. Higher wind load zones and longer purlin spans push toward the heavier end of the range. Aluminium roofing is typically 0.7–0.9 mm due to its lower yield strength.
What is the difference between BMT and TCT?
BMT is base metal thickness — the steel substrate without coatings. TCT is total coated thickness — the steel plus the zinc or aluminium-zinc coating. The structural calculations are based on BMT. When ordering material, confirm whether the thickness is BMT or TCT — a sheet specified as 0.55 mm TCT has a BMT of approximately 0.47–0.50 mm, which is what counts for structural design.