Facade substitutions delay projects because the replacement product almost never arrives with the compliance evidence the project actually needs. A substitute that looks equivalent on a data sheet still requires its own NATA-accredited test reports, its own certifier review, and its own sign-off from the design team - and that process takes weeks or months, not days.
Where does the substitution come from?
It usually starts at procurement. A builder or installer finds a product that is cheaper, has shorter lead times, or is simply available when the specified product is not. The specification includes the phrase “or approved equivalent,” and someone treats that as an open invitation to swap.
The problem is not the intent behind the substitution. Cost and programme pressure are real. The problem is what “approved equivalent” actually requires once you start pulling the thread.
What does the certifier need to see?
For a facade product to satisfy evidence of suitability requirements under the NCC, the certifier needs to verify that the product meets the relevant performance criteria - and that means documentation, not promises.
At a minimum, a substituted cladding product on a Class 2 or higher building will need:
- AS 1530.1 test report from a NATA-accredited laboratory confirming non-combustibility
- AS/NZS 4284 weather performance report demonstrating the system meets wind and water resistance under the relevant service loads
- Product data sheets covering material composition, thickness, tolerances, and structural capacity
- Installation instructions that match the proposed application - orientation, fixing method, substrate compatibility
If the original specification was for a solid aluminium system like element13 or an interlocking rainscreen like interloQ, the substitute needs to demonstrate equivalent performance across all of those criteria. Not just one. All of them.
Why does this take so long?
NATA-accredited testing is not something a supplier can produce on request. AS 1530.1 combustibility testing and AS/NZS 4284 facade testing are conducted by accredited laboratories - CSIRO, Warringtonfire, or similar - under controlled conditions. The test applies to a specific product configuration, not a product family or a general material type.
If the proposed substitute does not already have these reports, the supplier needs to commission the testing. That alone can take six to twelve weeks, assuming laboratory availability. If the product is imported, test specimens may need to be shipped from overseas.
Meanwhile, the certifier cannot approve. The architect may need to reassess design intent - colour, profile, joint detail, overall aesthetic. The facade engineer may need to verify structural adequacy for the specific wind region and building height. None of this happens in parallel with procurement. It happens instead of it.
What if the substitute has a composite core?
This is where substitutions can move from a delay into a dead end. If the proposed alternative is an aluminium composite panel with a polyethylene or mineral-filled core, it will not pass AS 1530.1 as non-combustible. The core material is combustible, regardless of the aluminium skins.
For buildings where the NCC requires non-combustible external wall cladding under the Deemed-to-Satisfy provisions, a composite panel is not an equivalent. It is a fundamentally different product classification. The only pathway forward would be a Performance Solution - which introduces its own timeline, cost, and specialist involvement.
A substitution intended to save money can end up requiring a fire engineering assessment that costs more than the price difference between the two products.
The “or approved equivalent” clause
This specification language is the root cause of most substitution disputes. It is meant to provide flexibility, but in practice it defers a compliance decision to the construction phase - exactly when there is the least time and the most pressure.
In NSW, the Design and Building Practitioners Act adds another layer. Registered practitioners must declare that the building work complies with the Building Code of Australia. A mid-project substitution means the practitioner needs to reassess and re-declare - which they will not do without complete documentation for the replacement product.
The result is a loop: the builder proposes a substitute, the certifier asks for evidence, the supplier cannot produce it quickly enough, and the project waits.
How to avoid the loop
The most effective way to prevent substitution delays is to start with a product that has complete, current, NATA-accredited documentation ready to submit from day one. That means AS 1530.1, AS/NZS 4284, structural testing, and a compliance pack that addresses the certifier’s requirements for that specific NCC pathway.
Valmond & Gibson supplies non-combustible aluminium facade systems - including interloQ interlocking rainscreen panels and element13 solid aluminium panels - with full compliance packs prepared for project submission. Not because it eliminates the possibility of substitution, but because it removes the reason for it. When the documentation is already there, the project does not need to go looking for an alternative.
The specification stage is where this gets resolved. Clear product nomination, explicit performance criteria for any proposed equivalent, and a defined approval process before construction starts. That is the difference between a substitution clause that protects the project and one that delays it.
For compliance documentation or technical support on your next facade project, contact the Valmond & Gibson team.
Related Reading
- The Real Cost of Specification Gaps on Facade Projects
- Navigating ‘Or Approved Equivalent’: Compliance Risks in Facade Projects
- How to Build a Compliant Facade Documentation Pack
- Evidence of Suitability Under NCC 2022: What Certifiers Actually Need
Last updated: 4 April 2026