Australia's building code has a standard path and a performance path. For mass timber the standard path stops at about eight storeys, and it stops sooner still if the timber is to be left exposed. Above that line a building is approved on a performance-based case or it is not approved at all. That is not a loophole. It is the other half of the code, and it costs time, money and a team that has done it before.
Where the standard path stops
The Deemed-to-Satisfy provisions are the code's prescriptive recipes: follow them and compliance is not argued. Timber earned its place in them in 2016, after fire testing run through Forest and Wood Products Australia took the case to the building code board. That concession has a ceiling. WoodSolutions puts it at 25 metres of effective height in its mid-rise guide, roughly eight storeys.
Above the ceiling there is no recipe to follow. As far as the prescriptive provisions are concerned, a fifteen-storey timber building is not a taller version of an eight-storey one. It is a building they do not address.
What a performance-based case is
The code's Performance Requirements sit above the Deemed-to-Satisfy provisions. Meeting a Performance Requirement by another route is compliance, equally. A fire engineer builds the evidence that the building does, and it usually rests on several things at once:
- Sprinklers first: the primary system, designed and assessed for reliability rather than assumed to work.
- Self-extinction: the timber designed to stop burning once the contents of the compartment are spent, instead of continuing to feed the fire.
- Charring and separation: the structure sized to carry its load after a known depth of char, with the floors still separating after it.
- Evacuation and brigade intervention: modelled rather than assumed, because the numbers change with height.
- Peer review: an independent fire engineer checks the case, and the building surveyor and the authority have to accept it.
What it costs, in time and in money
- The fire engineer is an early appointment, not a late one. The case shapes the section, the core and the services, so it has to be settled while the drawings can still move.
- Peer review and authority engagement add months rather than weeks, and they add them before lodgement, not after.
- Fees are higher than on a Deemed-to-Satisfy job, and the work is front-loaded, which is a cashflow question as much as a fee question.
- The documentation is heavier, and it has to survive the builder's engineers and the insurer's as well as the authority's.
What it changes for the owner
- You get the thing you are paying for. Exposed timber is the reason to build in timber at all. Boxed in behind plasterboard it is a structural choice nobody can see and few tenants will pay for.
- Programme risk moves earlier. The uncertainty sits in the approval, where it can be managed, instead of in construction, where it cannot.
- Financiers and insurers will ask. Have the fire engineering answer ready in the form they want it, because the question arrives with the term sheet.
Who you need, and when
- The fire engineer, before the architect fixes the section. Appointing them after the scheme is set means redesigning it.
- The structural engineer, alongside them, because char depth, connections and member sizes are one conversation, not three.
- The building surveyor, early, since they have to accept the case and can tell you now what they will not wear.
- A development manager who owns the approval strategy, what it costs and the programme it drives, and who sits between the engineers and the authority.
When it is worth doing
It is worth it when the exposed timber is doing commercial work: an embodied carbon result the market will pay for, a rating the tenants want, a building that leases on what it is made of. It is not worth it to prove a point. If the timber can be covered without hurting the building's case, the Deemed-to-Satisfy path is cheaper, faster and better understood, and it should be taken.
On Stephenson Street
57–71 Stephenson Street in Cremorne is fifteen storeys and 57.9 metres to the roof, with cross-laminated timber floors on glulam columns and the timber left visible. Carbon Fire Engineering prepared the performance-based case, AECOM the structure, and Edition Office is the architect. The application went in under the state's Development Facilitation Program, which puts the decision with the Minister for Planning rather than the council. It went on public notice in September 2026 and has not been decided.
Vettex has run the development from the first feasibility, and that includes owning the approval strategy: what the case has to prove, who proves it, what it costs and how long it adds.