Materials / Coated Steel
Zincalume Steel Battens, Explained
The silver finish on a steel batten is doing more work than it gets credit for. Here is what that coating actually is and how it stacks up against galvanised. We also cover what the Australian Standards require, and where to buy battens made from it in Adelaide.
SEC 01 / The science
The science behind zincalume coating
It is a metallic coating, hot dipped onto the steel strip before the batten is ever rolled.
The current generation of the coating is an aluminium, zinc and magnesium alloy. It runs at roughly 55 per cent aluminium, with small additions of magnesium and silicon. The balance is zinc. Each metal has a job. Aluminium forms a stable barrier layer. Zinc protects sacrificially, corroding first so the steel does not. Magnesium sharpens that self protection at the places coatings fail first: cut edges, scratches and screw penetrations.
One strip, three layers. The AM125 class puts a minimum of 125 g/m2 of alloy across the two faces combined.
SEC 02 / Vs galvanised
Zincalume vs galvanised steel
Galvanised steel wears a coating of zinc alone, designated with a Z class such as Z275. Zinc’s sacrificial protection is excellent. It is why galvanising has survived for more than a century. The catch is that zinc is consumed as it works. The aluminium rich alloy adds a barrier that is not consumed the same way. In typical open air exposure, a coated sheet of comparable class is generally expected to outlast a galvanised one.
Galvanised still earns its place. It behaves well in contact with fresh concrete and mortar. It also suits some rural and agricultural settings. Those uses keep Z coatings in specifications for good reason. The point is not that one coating is universally better. The alloy coating is simply the modern default for roofing, ceiling and framing components. That is why quality battens are rolled from it.
SEC 03 / Roofs and ceilings
Benefits for roofing and ceiling applications
Battens live in a hard part of the building. A roof cavity cycles from hot and dry to cold and damp overnight. Condensation forms exactly where the battens sit. The alloy coating is built for that duty. It protects through wet and dry cycling and holds up around fastener penetrations. It keeps doing so for decades. There is no rot, no swelling, and no termite exposure of the kind timber battens bring.
That is the material story behind our steel roof battens and steel ceiling battens. Both are rolled from coated G550 high tensile steel, as 40mm and 22mm top hat profiles. The corrosion protection is on the coil before it ever reaches the roll former. Coating class matters more near the coast, where salt loads climb. So do washdown zones. Tell us where the build is and we will talk it through.
SEC 04 / Standards
Australian standards for zincalume products
The governing document is AS 1397, the standard for continuously hot dip metallic coated sheet steel and strip. It covers both the steel base and the coating. Every compliant coil also gets a plain language designation. AS 1397/G550/AM125 means the standard, G550 steel at 550 MPa minimum yield, and an AM coating of at least 125 g/m2.
If the steel is not marked, treat it as unproven.
AS 1397 requires compliant product to be clearly and durably marked. The marking carries the standard, the base thickness and the designation, or the packaging does. Unmarked coil might be made to anything. A test certificate without matching markings proves very little. Ask to see the designation before the steel goes on a roof.
SEC 05 / Adelaide supply
Sourcing zincalume battens in Adelaide
Kspan rolls battens in Adelaide from coated G550 high tensile steel to AS 1397. The range covers a 22mm ceiling profile and a 40mm roof profile. Lengths run at a standard 6100mm, or as custom runs. The coating class is confirmed on the data sheet for every order. Quotes go out within one business day. Despatch runs across metro and regional South Australia, so the coil to site distance stays short.
Coated battens, rolled in Adelaide
Send the profile, BMT, lengths and volume. We confirm the steel designation on the data sheet, quote within one business day and despatch across SA.
ZINCALUME® and Activate® are registered trade marks of BlueScope Steel Limited. The term is used here in its everyday trade sense for aluminium/zinc alloy coated steel. Kspan is an independent fabricator and is not affiliated with BlueScope. Coating classes, designations and warranties vary by product and environment. Confirm the data sheet for your specific order before specifying.
