Before you open a colour chart, you need to settle on a profile. The profile governs the minimum roof pitch your design can achieve, whether fasteners are exposed or hidden, how the roof drains, what it costs per square metre, and the architectural character of the finished building. Colour is cosmetic. Profile is structural.
All four profiles discussed here are available in BlueScope COLORBOND steel and are covered by AS 1562.1, the Australian standard for the design and installation of sheet roof and wall cladding in metal. That standard sets out requirements for fastener spacing, end laps, side laps, and minimum pitches based on profile geometry and local wind and rain exposure. Any installer working to the NCC 2025 is expected to comply with AS 1562.1 as the primary referenced document for metal roofing.
With that foundation in place, here is how the four main profiles compare.
Corrugated (Custom Orb): The Heritage Workhorse
Profile shape: Sinusoidal corrugations, 76 mm pitch, 17 mm depth. The wave runs continuously from ridge to eave with no flat pan between ribs.
Fixing method: Pierce-fix. Fasteners pass through the crest of each corrugation and are visible from ground level. Neoprene-seated hex-head screws or traditional lead-head nails are used depending on the substrate.
Minimum pitch: Approximately 5 degrees for standard installations, though some manufacturers specify higher minimums depending on sheet length and rainfall intensity zone. AS 1562.1 requires end laps on lower pitches, which adds material cost.
Cost: Corrugated is the most affordable profile. The roll-forming process is simple, the profile has been in continuous production for over 150 years, and sheet widths are standardised. Expect to pay less per linear metre than any of the profiles below.
The look it gives: Corrugated reads as distinctly Australian. It suits federation-era homes, Queenslanders, rural sheds, farm buildings, and coastal cottages. On a contemporary build it can work as a deliberate contrast, but it does not naturally suggest a modern architectural language. If a heritage overlay or council DCP requires a corrugated profile, this is your only compliant option.
Where it excels: Heritage restorations, verandah re-roofing, curved applications. Because the sinusoidal profile is flexible across its width, corrugated sheet can be curved on site around a barrel vault or bullnose verandah without specialist equipment, provided the radius is not too tight. This is something none of the other three profiles can do.
Where it falls short: The exposed fasteners require periodic inspection and re-torquing. On long sheets at low pitches, water can pond at laps. The 5-degree minimum pitch rules it out for shallow skillion designs.
Trimdek: The Reliable All-Rounder
Profile shape: Trapezoidal ribs at 200 mm centres, 29 mm deep, with a flat pan between each rib. The geometry is more angular than corrugated and reads as cleaner and more contemporary.
Fixing method: Pierce-fix. Fasteners go through the pan of the sheet, not the rib crest. Pan fixing is generally considered more weather-resistant than crest fixing because the fastener sits lower and the washer seal is under less stress, but the screws remain visible.
Minimum pitch: Approximately 3 degrees for standard single-span applications, making it suitable for a wider range of roof geometries than corrugated.
Cost: Moderately priced. More material is consumed in forming the trapezoidal rib than a corrugated wave, so Trimdek sits above corrugated in price but well below concealed-fix profiles.
The look it gives: Trimdek is the most common profile on residential and light commercial buildings across Australia. It is not as visually distinctive as corrugated and not as sleek as Klip-Lok. On a standard suburban home it reads as neutral and practical, which is exactly what many builders and clients want.
Where it excels: New homes, extensions, garages, industrial sheds, and any project where budget and a 3-degree pitch capability need to coexist. The profile is widely stocked, meaning lead times are short and replacement sheets are easy to source years later.
Where it falls short: The exposed fasteners are still a maintenance consideration. It does not curve. On architecturally ambitious projects, the profile may look utilitarian rather than considered.
Spandek: The Transition Profile
Profile shape: High-tensile trapezoidal ribs at 300 mm centres, 38 mm deep. The wider rib spacing and greater depth give Spandek a more pronounced shadow line than Trimdek and a stronger visual rhythm across a roof plane.
Fixing method: Pierce-fix through the pan, similar to Trimdek, though some Spandek variants are available in concealed-fix configurations depending on the manufacturer and substrate. Confirm with your supplier which fixing system applies to the specific product you are ordering.
Minimum pitch: Approximately 2 degrees for standard applications, which opens up low-pitch skillion roofs that neither corrugated nor Trimdek can serve.
Cost: Higher than Trimdek due to the deeper rib geometry and higher-tensile base steel typically used. Still below Klip-Lok in most markets.
The look it gives: Spandek has a more architectural quality than Trimdek. The wider rib spacing creates stronger shadow lines and the profile reads as intentional rather than default. It suits contemporary residential builds, commercial facades used as wall cladding, and industrial projects where the building envelope is part of the design intent.
Where it excels: Low-pitch skillions, contemporary residential builds, and projects where the designer wants a more pronounced profile without moving to a fully concealed-fix system. The 2-degree minimum pitch is a genuine advantage on flat-looking roof forms.
Where it falls short: Spandek does not curve. Fasteners are still exposed. On very long spans the wider rib spacing means fewer fastening points per unit area, so wind uplift calculations need careful attention under AS 1562.1.
Klip-Lok: The Concealed-Fix Premium Option
Profile shape: High-tensile trapezoidal ribs at 333 mm centres, 38 mm or 47 mm deep depending on the variant (Klip-Lok 406 and Klip-Lok 700 are the two main systems). The pan is broad and flat. The rib is taller and more defined than any pierce-fix profile.
Fixing method: Concealed-fix. A clip is fastened to the structural substrate and the sheet rib snaps over the clip. No fastener penetrates the sheet. This eliminates the primary source of water ingress in metal roofing and removes the maintenance requirement of checking and replacing failed screw seals.
Minimum pitch: Approximately 1 degree for Klip-Lok 700, making it suitable for near-flat roof applications that would be impossible with any pierce-fix profile. This is the profile that makes a flat-looking contemporary roof achievable in steel.
Cost: The most expensive of the four profiles. The clip system adds material cost, installation is slower because clips must be positioned and fixed before sheeting proceeds, and the higher-tensile base steel commands a premium. Expect to pay noticeably more per square metre installed compared to Trimdek.
The look it gives: Klip-Lok is the profile of choice for contemporary architecture. The broad flat pan, the absence of visible fasteners, and the strong shadow line from the tall rib create a roof that reads as part of the architectural composition rather than a functional afterthought. It is common on architecturally designed homes, commercial buildings, and prestige residential projects.
Where it excels: Low-pitch skillions, flat-looking roofs on contemporary homes, long-run commercial applications, and any project where the client or architect has specified a concealed-fix system. The absence of penetrations also makes Klip-Lok the preferred choice in high-wind and high-rainfall zones where fastener integrity is a long-term concern.
Where it falls short: Cost. Klip-Lok does not curve. It requires a competent installer familiar with the clip system; incorrect clip spacing is a common installation error that can affect both wind performance and thermal movement. And on a heritage or traditional home, the profile looks out of place.
Choosing the Right Profile for Your Project
The decision tree is straightforward once you know your pitch, your budget, and your architectural intent.
- Heritage home or curved verandah: Corrugated (Custom Orb). No other profile replicates the sinusoidal wave, and no other profile curves on site.
- Standard residential or commercial build on a conventional pitch: Trimdek. Reliable, affordable, widely available, and proven across decades of Australian construction.
- Contemporary build or low-pitch skillion at 2 degrees or above: Spandek. The deeper profile and lower pitch capability suit modern roof forms without the cost of a concealed-fix system.
- Near-flat roof, prestige residential, or long-run commercial: Klip-Lok. The 1-degree minimum pitch and concealed fixing are the specification that makes this profile worth the premium.
Pitch, fixing method, and budget narrow the field quickly. Aesthetics then determine the final choice within whatever options remain viable.
All four profiles are available in the full COLORBOND colour range, so once the profile decision is made, colour selection proceeds against a fixed set of constraints rather than an open field. That is the correct order of decisions.
AS 1562.1 applies to all four profiles. Fastener type and spacing, end lap dimensions, and minimum pitches must be confirmed against the manufacturer's current installation instructions and the requirements of the standard for your specific wind region and roof geometry. Do not rely on generic rules of thumb when the project is in a cyclonic zone or has an unusual span.
For cut-to-length sheets, flashings, and trade pricing across all four profiles, visit acsupplies.com.au or contact the ACS trade desk for a quote on your next project.