The National Construction Code is the technical rulebook every build follows — but two things trip tradies up: only the Performance Requirements are actually mandatory (DtS is just one way to meet them), and each state adopts the NCC on its own timeline with its own variations. Here is the map, including where NCC 2025 has and has not landed.
What the NCC is
The NCC is Australia's primary technical standard for building and plumbing, updated on a 3-year cycle (2019, 2022, 2025) by the Australian Building Codes Board (ABCB) on behalf of the Commonwealth and states. Each jurisdiction then adopts it into law — often with its own variations — through its building legislation. It comes in three volumes:
- Volume 1 — Class 2-9 (commercial, multi-residential, public buildings).
- Volume 2 — Class 1 and 10a (houses, townhouses, garages, sheds) — where most residential tradies live.
- Volume 3 — the Plumbing Code of Australia (for licensed plumbers and drainers).
Performance Requirements vs DtS vs Performance Solutions
This is the structural idea to grasp: only the Performance Requirements are mandatory. There are then two ways to meet them:
- Deemed-to-Satisfy (DtS) — follow the specific prescriptive details in the NCC and its referenced standards (materials, sizes, clearances, build-ups) and you are automatically deemed to comply. This is the default for most residential work — wall and roof build-ups, stair dimensions, fire ratings, waterproofing and energy details.
- Performance Solution — an alternative design that meets the same Performance Requirement a different way, justified with an assessment method (fire testing, energy modelling, a DtS comparison or expert report) and a performance-based design report. You use one when the design cannot meet DtS exactly, when an alternative is cheaper or more practical, or when you are chasing higher performance or innovation. Small residential mostly stays DtS.
NCC 2025 — published, but adopting on a stagger
NCC 2025 was published on 1 May 2026, but "available for adoption" is not "in force" — each jurisdiction sets its own start date. As things stand (mid-2026):
- VIC — adopted from 1 May 2026.
- ACT — optional from 1 May 2026, mandatory 1 November 2026.
- NSW and QLD — deferred to 1 May 2027 (still on NCC 2022 until then).
- SA — from 1 May 2027 (with some alterations able to use older provisions out to 2030).
- TAS — signalled it will freeze rather than take up NCC 2025.
Always check your state's current adoption status before you rely on a 2025 clause — and note ministers agreed a pause on further residential NCC changes until ~2029 for stability. NCC 2025 is an evolution, not a revolution over 2022: tighter energy (Section J and residential), more explicit condensation and moisture detailing, clarified waterproofing, clearer structural and fire links, and a new register of alternative reference documents (updated standards usable between cycles).
What is in Volume 2 for residential tradies
The sections you will actually touch: governing requirements (definitions, evidence of suitability, documentation); structural and site (footings, slabs, framing, bracing, tie-down, retaining walls); fire safety and separation (between units, to boundaries, eaves); health, amenity and moisture (wet-area waterproofing, ventilation, condensation); and energy efficiency (insulation, glazing, sealing, assessment methods).
State variations — the patchwork
The NCC is national, but each jurisdiction can vary a clause or add requirements on adoption — and those overrides are the law in that state. The patchwork is real and growing: NSW, for instance, went from around 16 variations under NCC 2022 to 210+ under NCC 2025. The workflow: check the NCC jurisdictional appendix for your state, then cross-check the regulator's bulletins and the HIA/MBA summaries for recent changes and transition dates.
Common mistakes
- Treating DtS as "the law" — it is one compliance path; Performance Solutions are equally valid.
- Assuming NCC 2025 applies everywhere — it is staggered (NSW/QLD/SA still on 2022 into 2027).
- Ignoring state variations and building to the generic NCC.
- Reaching for a Performance Solution on small residential where DtS would do.
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