The facade on a mixed-use building must satisfy the NCC requirements for every classification within the building - not just the most prominent one. When a single structure contains retail, commercial, and residential uses, the construction type is set by the most onerous classification. That construction type applies to the whole building, including the external walls.
This catches people out. The assumption that lower-level commercial floors have less demanding facade requirements than the residential levels above is wrong. Here is how the NCC handles it and what it means for facade specification.
How does the NCC classify a mixed-use building?
Each part of a building is classified according to its use. A typical mixed-use tower might contain Class 6 (retail) at ground level, Class 5 (office) on mid-levels, and Class 2 (residential) on upper levels. The NCC requires each part to be classified separately under Section A of Volume One.
The construction type for the overall building is then determined by two things: the most onerous classification present in the building, and the total rise in storeys. A 10-storey building containing any combination of Class 2, 5, and 6 occupancies will be Type A construction - the most restrictive type under the NCC.
This is the point that matters for facades. The construction type is not applied floor by floor or classification by classification. It applies to the building as a whole.
Can you use combustible cladding on the commercial levels?
No. Once the building is classified as Type A construction, the NCC requirement for non-combustible external walls applies to the entire building. You cannot use combustible cladding on the Class 6 retail podium simply because that part of the building, taken in isolation, might permit it.
The logic is straightforward. A fire that starts in a ground-floor tenancy does not respect classification boundaries. The facade is continuous from ground to roof. If the external wall material on lower levels can contribute to fire spread, the fire performance of the residential levels above - where people sleep - is compromised.
The NCC treats the building envelope as a single system, and the facade specification must follow that approach.
How do fire compartment boundaries affect the facade?
Mixed-use buildings require fire compartmentation between different classifications. The boundary between a Class 6 retail tenancy and a Class 5 office level, or between a Class 5 office and a Class 2 residential floor, must be a fire-rated separation.
Where these compartment boundaries meet the external facade, the fire rating must be maintained. This means the junction between the compartment wall or floor and the facade system needs to be detailed to prevent fire and smoke passing through the gap. In practice, this involves fire-rated perimeter seals, fire-stopping at slab edges, and careful coordination between the facade system and the fire compartment construction.
For curtain wall systems, this junction is critical. The gap between the slab edge and the curtain wall framing - sometimes called the linear gap or spandrel gap - must be sealed with fire-rated materials that maintain the compartmentation rating. The facade engineer, fire engineer, and certifier all need to be satisfied that this detail works.
What are the spandrel requirements between levels?
The NCC requires separation between openings on different storeys to prevent fire spreading vertically up the facade from one level to the next. This is achieved through spandrel panels or other fire-resistant construction between the head of one opening and the sill of the opening above.
In a mixed-use building, these spandrel requirements apply at every level transition - not just between different classifications. But the transitions between different use types often receive closer scrutiny from certifiers, particularly the junction between commercial and residential levels.
The spandrel zone needs to be non-combustible, provide the required fire resistance level, and extend for the distance specified in the NCC. Early engagement with the facade system supplier helps avoid redesign later.
Why does a non-combustible material platform simplify mixed-use facades?
When the entire facade material palette is non-combustible, the classification-by-classification compliance argument becomes simpler. You are not trying to demonstrate that a combustible product is acceptable on certain levels while non-combustible products are used on others. One compliance framework covers the whole building.
Valmond & Gibson’s product range - interloQ interlocking rainscreen panels, element13 solid aluminium panels, 165CW unitised curtain wall, and conneQt aluminium battens - is non-combustible throughout, tested to AS1530.1 by CSIRO. This means a mixed-use facade can use different V&G systems on different levels to suit the architectural intent, while maintaining a consistent non-combustible compliance position across the full height of the building.
A common configuration on a mixed-use project might use 165CW curtain wall for the retail and commercial glazing levels, element13 for spandrel panels and solid facade zones, interloQ for the residential cladding above, and conneQt for screening and architectural features. Different products, different appearances - but all non-combustible, all documented under one compliance pack, and all from a single supplier who understands how the systems interface with each other.
Where different facade systems meet on the same building, the junction details, fire-stopping coordination, and structural load paths need to work together. Having one supplier across the full facade simplifies that coordination considerably.
Working on a mixed-use project with multiple NCC classifications? Get in touch for compliance documentation and technical support across the full V&G product range.
Related Reading
- NCC Facade Requirements by Building Class
- Fire Resistance Levels and External Walls
- Choosing the Right Aluminium Facade System
- Aluminium Facades for Retail and Mixed-Use
Last updated: 4 April 2026