Specifying aluminium cladding for an Australian project requires two distinct decisions, and conflating them is one of the most common gaps we see in early-stage specifications. The first decision is panel format — the physical shape, fixing method, and aesthetic expression of the cladding. The second is system strategy — how the wall assembly behind that cladding manages water, ventilation, and pressure. A specification that names a panel format but says nothing about system strategy is incomplete. This guide breaks both decisions apart so you can make them deliberately.
Two decisions, not one
When a specification says “aluminium cassette cladding,” it describes a panel format. It tells you the panels are folded trays with shadow-gap joints. What it doesn’t tell you is whether those cassettes sit on a ventilated cavity with a drained and vented rainscreen strategy, or whether they’re fixed directly to a substrate with no cavity at all. The performance difference between those two configurations is enormous — one manages water through drainage and pressure equalisation, the other relies entirely on the panel joints to keep water out.
Panel format covers shape, fixing method, and aesthetics. Think of it as the answer to: what does the facade look like and how do the panels attach?
System strategy covers how the wall assembly manages water and ventilation. Think of it as the answer to: what happens when water gets past the outer skin?
Both decisions need to be explicit in the specification. Neither implies the other.
Panel formats — how the cladding attaches and looks
Two panel formats dominate the Australian aluminium cladding market, each with distinct fabrication, fixing, and aesthetic characteristics.
Interlocking profiles
Interlocking panels are extruded aluminium sections that mechanically engage edge-to-edge. Each panel locks into its neighbour along a formed joint line, creating a continuous facade surface with no exposed fasteners. The concealed fixing is inherent to the panel geometry — the interlock itself is the fixing mechanism.
The tight joint line between panels isn’t just aesthetic. It adds a layer of water defence at every panel connection, making interlocking profiles naturally suited to exposed conditions. Installation is typically horizontal, producing a consistent linear rhythm across the facade. The regularity of the joint pattern gives interlocking facades a clean, disciplined appearance that reads well at scale.
V&G’s interloQ system is an example of this format — an extruded interlocking profile designed to work within a rainscreen configuration on an aluminium subframe.
Solid aluminium panel
Solid aluminium panels are single-skin sheets — typically 3mm thick — with no composite core, no adhesive layers, and no lamination. The panel is what it appears to be: a solid piece of aluminium. That simplicity is the point. There’s nothing inside a solid aluminium panel that can burn, which means zero combustibility ambiguity. What you test is what you install.
Solid panels can be supplied and installed in two ways depending on the project’s aesthetic and fixing requirements:
-
Flat sheet — the panel is supplied flat and fixed to the subframe via face fixings (visible fasteners) or concealed clips. This is the simplest, most direct approach.
-
Cassette (folded tray) — the same solid aluminium sheet is folded into a tray shape with turned-up edges (returns) on all four sides. The returns allow concealed clip fixing for a completely clean face, and shadow-gap joints between panels create depth and definition. Cassettes involve more fabrication steps and are custom sized to project dimensions, which adds lead time — but they give designers precise control over panel proportions and layout.
Whether flat or cassette, the material is the same: solid aluminium, non-combustible, no core. The fabrication method is a project-level decision based on aesthetics, fixing preference, and programme.
V&G’s element13 is a 3mm solid aluminium panel that passes AS 1530.1 as a material, full stop.
What about composite panels (ACPs)?
Aluminium composite panels — two thin aluminium skins bonded to a core material — dominated the Australian cladding market for decades. Then the Lacrosse apartment fire in Melbourne (2014) and the Grenfell Tower disaster in London (2017) exposed the catastrophic risk of polyethylene-core ACPs in multi-storey applications.
Australia’s regulatory response was decisive. The NCC tightened non-combustible requirements for external walls, state governments launched cladding audits and remediation programs, and the industry began shifting away from composite panels entirely.
Mineral-core ACPs exist and can meet non-combustibility requirements, but they still carry market perception risk. Many certifiers, builders, and building owners now prefer to avoid the composite category altogether — not because mineral-core products are necessarily non-compliant, but because the simplest compliance path is a product with no core material to question. This is the market dynamic driving the shift toward solid aluminium systems.
System strategy — the rainscreen principle
For the project types V&G typically supplies — multi-storey residential, commercial, institutional, and cladding remediation — there is essentially one system strategy worth specifying: the rainscreen (ventilated cavity) approach.
NCC 2025 makes this even more explicit. New condensation management provisions are banning direct-fix cladding in climate zones 6 through 8 — covering Melbourne, Canberra, Hobart, and highland regions — and mandating ventilated drained cavities behind external cladding. Even outside those climate zones, ventilated cavity construction is now standard practice on any NCC-regulated building of consequence. Direct-fix cladding still has a place on low-rise, low-exposure structures, but it’s not where the specification complexity lies.
How rainscreen works
A rainscreen wall assembly has three functional layers:
-
Outer cladding — the aluminium panels. This is the first line of defence, shedding the bulk of wind-driven rain before it reaches the wall structure. The cladding doesn’t need to be watertight; it needs to manage the majority of water.
-
Ventilated air cavity — typically 25–50mm deep, sitting between the back of the cladding and the weather-resistant barrier. This cavity serves three purposes: it drains any water that penetrates the cladding joints, it ventilates moisture out of the wall assembly, and it helps equalise air pressure across the cladding face (reducing the pressure differential that drives water through joints).
-
Weather-resistant barrier (WRB) — the membrane or wrap behind the cavity. This is the true waterproofing line. Any water that makes it through the cladding and into the cavity hits the WRB and drains down to flashings at the base.
The subframe system — typically galvanised steel top hat battens on steel stud framing — spans the cavity and provides the fixing points for the cladding panels. The subframe defines the cavity depth and must allow unimpeded drainage and ventilation.
Either panel format can be used in a rainscreen configuration. Both interlocking profiles and solid aluminium panels mount to a subframe with a cavity behind them. The panel format determines how the facade looks and how the panels attach; the rainscreen strategy determines how the wall assembly performs.
Why it matters for specification
Consider the same solid aluminium panel in two configurations:
-
Panel on a ventilated cavity with WRB, drained base flashings, and ventilation gaps top and bottom = a rainscreen system. Water management is handled by the cavity and barrier.
-
Same panel direct-fixed to a substrate with sealed joints = a face-sealed system. Water management relies entirely on the sealant at every joint. No drainage path, no ventilation, no pressure equalisation.
These are fundamentally different systems using the same panel. The specification must define both the panel format and the system configuration. This is exactly what facade engineers assess and certify — not just the cladding product, but the complete wall assembly and its performance characteristics.
The Australian compliance context
Three compliance areas matter most for aluminium cladding specification in Australia: fire performance, weatherproofing, and evidence of suitability.
Non-combustibility (AS 1530.1)
The NCC requires non-combustible external walls on Type A and Type B construction — which covers essentially all multi-storey buildings. The compliance test for material-level non-combustibility is AS 1530.1.
Solid aluminium passes AS 1530.1 as a material. There’s no ambiguity, no reliance on specific panel configurations or assembly details. The material itself is non-combustible, and that’s the end of the conversation at the material level.
Weatherproofing (AS/NZS 4284)
AS/NZS 4284 is the facade testing standard that assesses water penetration resistance, air infiltration, and structural performance under wind load. Unlike AS 1530.1, this standard tests the system configuration — the complete assembly of panels, fixings, subframe, seals, and flashings — not just the panel material.
Rainscreen systems that have been tested to AS/NZS 4284 in specific configurations provide documented evidence of weatherproofing performance. This evidence is how you demonstrate compliance with NCC performance requirements through verification methods. When evaluating cladding systems, ask for the test configuration details — which panel, which subframe, which cavity depth, which seals — because the test result only applies to what was actually tested.
Evidence of suitability
NCC 2025 reinforces the requirement for evidence of suitability for all building products used in NCC-regulated construction. This means test reports, certificates of conformity, technical assessments, and installation manuals must be available and must support the specific application.
Well-documented cladding systems with clear test evidence, detailed installation guides, and defined system configurations streamline the approval process. Certifiers can assess compliance more efficiently when the documentation package is complete and specific.
For a deeper look at how these requirements work together, see our guide to non-combustible cladding and NCC compliance.
Choosing the right combination
The panel format decision and the system strategy decision are driven by different factors.
Consideration Interlocking profile Solid aluminium panel
Aesthetic Linear rhythm, tight joints, consistent pattern Flat face — supplied as flat sheet or folded into cassette trays with shadow-gap joints
Fixing Concealed (mechanical interlock) Face-fixed, clip-fixed, or concealed clip to cassette returns
Lead time Shorter (extruded, standard sections) Flat: moderate. Cassette: longer (custom fabrication)
Weight per m² Lighter (extruded profiles) Heavier (3mm solid aluminium)
Fire compliance Non-combustible (AS 1530.1) Non-combustible (AS 1530.1) — simplest compliance path, no core to question
Fabrication flexibility Fixed profile geometry High — flat sheets or custom cassette dimensions
Decision factors in practice:
-
Building height and exposure — higher buildings and more exposed sites favour systems with tested weatherproofing configurations and robust water management
-
Compliance pathway — if the simplest non-combustibility argument matters (remediation projects, risk-averse certifiers), solid aluminium panels remove ambiguity
-
Budget and programme — extruded interlocking profiles are generally faster to deliver; solid panels fabricated into cassettes offer more design flexibility but need more fabrication time
-
Aesthetics — this is often the starting point, and legitimately so. The panel format is the visible decision. Just make sure the system strategy follows
The key point: the panel format is often an aesthetic and budget decision. The system strategy is a performance and compliance decision. Specify both. Explicitly.
Getting the specification right
If you’re developing a facade specification for an Australian project and want to talk through system options, test data, or compliance documentation, V&G’s team can help. We supply aluminium cladding systems — interlocking profiles and solid aluminium panels — with tested rainscreen configurations and the technical documentation to support certification.
Start with what the project needs, and we’ll help you match the right panel format and system configuration to deliver it.
Related Reading
- Choosing the Right Aluminium Facade System for Your Project
- interloQ Specification Guide: Everything You Need to Know
- element13 Specification Guide: Solid Aluminium Cladding for Australian Projects
- Rainscreen vs Direct-Fix Cladding: When to Use Each System
Last updated: 15 February 2026