NCC 2025 proposed changes released for consultation

What are the major changes being proposed?

The primary focus of the 2025 amendments is commercial and mixed use-residential buildings.  However, there are proposals that will impact housing and Class 1 buildings. These include more stringent condensation provisions and electrical vehicle pre-provisioning requirements for all new homes.

Another suite of commercial energy efficiency stringency increases. These will primarily affect Class 3, 5-9 buildings, but also common services in Class 2 buildings and mixed-use spaces. Apartment balcony waterproofing proposals are proposed alongside another uplift in stringency for the condensation management provisions for all residential classes.
 
HIA has developed a summary of the major changes to help members navigate the major amendments and what they mean. The headline changes include:

Condensation changes again

• Requiring any control layer or water barrier installed on the exterior side of the primary insulation layer to meet the vapour permeable requirements in all climate zones
• Extending the vapour permeability requirements for wall sarking for all climate zones
• Banning direct fix cladding solutions by mandating in climate zones 6-8:
  • the use of cavities in walls for construction; and
  • minimum ventilation and drainage in walls.
• Mandating dimensions of cavities in walls and roofs and changing the required ventilation dimensions and methods of calculation.

In addition to Class 1, these changes are proposed to apply to Class 2, Class 3 and 9c buildings.

Energy efficiency changes for houses (Class 1 buildings)

All new houses will need to achieve an increased electrical capacity via:

• Electric vehicle charging circuits and pre-provisioning equipment for one car parking space for all homes
• The provision of additional switchboard capacity to residential dwellings. This increases based on the presence of gas appliances.

Additional changes for houses 

• Concessions for certain patios, verandas and the like from fire separation requirements
• More stringent structural provisions for houses in wind region B2 requiring design in accordance with cyclonic wind standards
• Changing the requirements for thermal breaks of steel framing, proposing they also be used where metal battens are installed
• Extending the length of pipework allowed under AS 3500.2 to connect to an untrapped bath to a floor waste gully (In Volume Three).

For apartments (Class 2 buildings)

• Changing the requirements for thermal bridging of steel framing, by requiring a thermal break where metal battens are used
• Waterproofing and watershedding amendments requiring:
  
  • Management of sub-surface water on an allotment
  • Hobs, step downs from concrete balconies and methods of water disposal from balconies and roofs
  • Mandatory falls in substrates with narrow tolerance for finishes and falls and slab deflection.
• Electric vehicle charging circuits and equipment sufficient for all carparking spaces
• Provision for future battery installations
• Varying levels of Solar Photovoltaic arrays (or equivalent) based on climate zone, class, floor area and presence of gas appliances
• Expanding alternatives to include fire-protected steel alongside fire-protected timber as an accepted form of construction.

For commercial Class 3 & 5-9 buildings

Significant energy efficiency stringency increases for Commercial building Class 3, 5-9 buildings are a focus of the 2025 amendment. These include:

• Air-conditioning system efficiency, and ducting length restrictions
• Requirements for building sealing
• Insulation
• Solar emittance and solar reflectance of roof materials in place of solar absorptance
• Glazing
• Space heating
• Artificial lighting demand control
• Pump and fan efficiency
• Energy efficiency modelling verification methods have been amended to align with stringency increases for elemental provisions.

Electrification is a focus of the proposals (particularly at higher stringencies) which will require:

• That physical space and spare electrical capacity be provided for equivalent electrical appliances in future where gas appliances are installed
• Provision for future battery installations
• Varying levels of Solar Photovoltaic arrays (or equivalent) based on climate zone, class, floor area and presence of gas appliances
• Electric vehicle charging equipment quantified to be sufficient for 20% of the daily driving needs of all occupants of a Class 3, Class 5-9 building.

Other significant changes include:

• Increased fire safety for carparks (including open deck carparks) to mitigate fire risks associated with modern vehicles and car stackers.

How can you get a copy of the changes?

What do you need to do?

To find out more, contact HIA's Building Services team.

Email us