NCC 2025 Compliance Checklist for Australian Builders

The National Construction Code 2025 is the version of the NCC that most new residential building work in Australia is now assessed against. It brought meaningful changes to energy efficiency requirements, wet area waterproofing, condensation management, and the way certain structural and fire safety provisions are applied. For builders, the practical question is: what do I need to check on every project that I might have been doing differently on jobs approved before 2025?

Energy efficiency — the biggest practical change

NCC 2025 increased the minimum energy efficiency requirement for new Class 1 residential buildings (single dwellings) to 7 stars under the Nationwide House Energy Rating Scheme (NatHERS), up from 6 stars. For builders, this means thermal performance needs to be verified earlier in the design process. It also introduced a whole-of-home energy budget that accounts for heating, cooling, hot water and lighting — meaning the envelope performance and the mechanical systems need to be considered together, not separately.

Practically, this means your energy assessor needs to be involved at design stage, not just before DA submission. Changes to glazing, insulation specification, and orientation all affect whether the building will pass. Catching these issues late is expensive.

Wet areas — updated waterproofing requirements

The wet area waterproofing provisions in NCC 2025 (Part 10.2 of Volume Two) were updated to provide clearer guidance on membrane application, the extent of waterproofing in showers and bathrooms, and testing requirements. The key practical changes relate to the minimum height waterproofing must extend on walls adjacent to showers, and the classification of areas that require full waterproofing versus water-resistant treatment.

This is an area where defects tend to appear 5 to 10 years after completion, so getting it right at the time of construction matters. If your tiling subcontractor is following the same approach they used on jobs approved in 2022, they may not be meeting the 2025 requirements.

Condensation management

NCC 2025 introduced explicit condensation management provisions for the first time as a mandatory requirement rather than guidance. Builders in climate zones 6, 7 and 8 (southern states, alpine and sub-alpine areas) are most directly affected. The requirements cover vapour management in wall and roof assemblies and are designed to reduce the incidence of mould and structural damage caused by interstitial condensation.

For most builds in these zones, compliance involves specifying the right building wrap product and ensuring insulation placement does not create a condensation risk within the assembly. Your building designer should be specifying this, but the builder is responsible for confirming it is installed correctly.

A practical compliance checklist

For residential Class 1 buildings assessed against NCC 2025, these are the key items to verify:

• Energy rating certificate confirming 7-star NatHERS compliance (or equivalent DtS pathway)
• Whole-of-home energy budget assessment if using the whole-of-home pathway
• Waterproofing specification confirmed against Part 10.2 for all wet areas
• Condensation management specification for climate zones 6, 7 and 8
• Glazing specification consistent with the energy rating assessment
• Pool and spa safety barrier compliance if applicable (Part 3.9.3)
• Stairway and barrier dimensions against Part 3.9.1 and 3.9.2
• Roof drainage calculations for the relevant climate zone

State variations still apply

The NCC is a national document but states and territories can introduce variations through their own legislation. NSW, Victoria, Queensland and Western Australia all have state-specific variations to parts of the NCC. If your project is in one of these states, check the state-specific amendment schedule before relying solely on the NCC document itself.