A well-written facade specification clause eliminates ambiguity, prevents substitution disputes, and gives the installer and builder everything they need to price and procure accurately. If the clause is incomplete, the gaps get filled by assumptions - and assumptions on a facade project cost time and money.
This guide covers the essential elements every cladding specification clause should contain, the common trap that undermines them, and a worked example you can adapt for your next project.
What should a facade specification clause include?
A complete clause covers nine elements. Missing any one of them leaves a gap that someone downstream - the builder, the installer, or the certifier - will have to resolve without your input.
1. Product identification. Name the manufacturer, the product, and the specific profile or model reference. “interloQ interlocking rainscreen cladding by Valmond & Gibson” is unambiguous. “Aluminium cladding or equivalent” is not - it invites substitution claims and pricing uncertainty.
2. Material. State the alloy, temper, and thickness range. For extruded aluminium profiles: “Extruded aluminium alloy 6060/6063 T5, 1.8-3.5mm wall thickness.” For solid aluminium panels like element13, specify the sheet alloy, grade, and nominal thickness.
3. Finish. Specify the coating system, colour reference, and the standard it must comply with. “Interpon D2525 superdurable polyester powder coat, colour: [reference], to AS 3715.” This locks in the performance expectation - not just what it looks like on day one, but how it performs over 15-20 years of UV exposure.
4. Fire classification. State the standard and the result. “Non-combustible to AS 1530.1.” Where available, reference the specific test report: “(CSIRO report FNC12595, NATA accredited).” The test report number removes any ambiguity about which product was tested.
5. Weather performance. Specify the test standard and the pressure rating. “Tested to AS/NZS 4284:2008 at plus/minus 1500Pa SLS.” The pressure rating should reflect the project’s wind region and building height - this is where the facade engineer’s input feeds into the specification.
6. Orientation and installation method. State how the product is installed. “Horizontal orientation, concealed interlocking connection, on aluminium subframe.” This matters because it defines the system - not just the panel. It also prevents pricing confusion between different installation configurations.
7. Wind load requirement. Reference the structural design standard and the source of the design loads. “Facade to resist site-specific wind pressures per AS/NZS 1170.2. Refer structural engineer’s facade schedule.” Do not embed specific wind pressures in the specification clause itself - they belong in the facade schedule and change with height and orientation.
8. Warranty. State the minimum warranty period and what it covers. “Minimum 20-year warranty covering substrate and coating, when installed by qualified installer.” This is a meaningful differentiator between products, and installers and builders should be able to price it directly from the clause.
9. Standards compliance. List all referenced standards in one place. For a typical aluminium cladding specification, this includes AS 1530.1, AS/NZS 4284, AS/NZS 1170.2, and AS 3715. Listing them explicitly means nobody has to guess which standards you expect the product to be tested against.
What does “or approved equivalent” actually do?
Including “or approved equivalent” after a named product opens the door to substitution claims. It sounds like a reasonable flexibility measure, but in practice it transfers the assessment burden to the builder and certifier - neither of whom were involved in the original product selection.
If you have specified a product, you have done so for a reason - fire performance, warranty terms, tested system compatibility, or project-specific detailing. Adding “or approved equivalent” without defining what equivalent means undermines all of that work.
If alternatives genuinely are acceptable, the stronger approach is to define the minimum performance criteria any alternative must meet. Specify the fire test result, the weather performance rating, the warranty duration, and the installation compatibility requirements. Make the alternative prove itself against measurable criteria rather than leaving “equivalent” undefined.
What does a complete clause look like?
Here is an example specification clause for interloQ interlocking rainscreen cladding, structured to cover all nine elements:
Aluminium interlocking rainscreen cladding: interloQ by Valmond & Gibson. Extruded aluminium 6060/6063 T5. Interpon D2525 powder coat finish, colour [ref], to AS 3715. Non-combustible to AS 1530.1 (CSIRO FNC12595). Weather performance to AS/NZS 4284 at plus/minus 1500Pa SLS. Horizontal orientation, concealed interlocking connection on aluminium subframe. Facade to resist site-specific wind pressures per AS/NZS 1170.2. Minimum 20-year warranty (substrate and coating). Installed to manufacturer’s technical manual.
That clause gives the builder a clear scope to price, the installer a defined product to procure, and the certifier an unambiguous compliance path to assess. No assumptions required.
Where to get specification support
Valmond & Gibson can provide draft specification clauses for interloQ, element13, and 165CW on request. These are formatted for direct insertion into NATSPEC or project-specific specification documents and include the relevant test report references, standards, and warranty terms.
If you are working on a specification and want to confirm product suitability, fire test coverage, or system detailing for a specific application, contact our team - we will send through the documentation you need.
Related Reading
- The Real Cost of Specification Gaps on Facade Projects
- How to Write a Facade Specification for NCC Compliance
- How to Build a Compliant Facade Documentation Pack
- Why Builders Should Engage Facade Suppliers Before Tender
Last updated: 4 April 2026