The Australian Building Codes Board (ABCB) recently released the public comment draft of NCC 2025. Changes in the draft range from the transformational to the editorial and everything in between. Members will find a strong Back to the Future theme among the 1200- plus pages of amendments and analysis. This is because the main areas of focus for amendment include changes to areas only recently proposed or changed:

• waterproofing commercial buildings and concrete balconies, roofs, podiums and carparks
• condensation management for residential dwellings
• commercial energy efficiency, including mandatory photovoltaic arrays, pre-provisioning for electric vehicle charging and future battery installations.

HIA has kept abreast of changes via its involvement in working groups for waterproofing and condensation management with ABCB. We explain why some of this sounds familiar, the main changes for builders, suppliers and contractors, how you can be involved and what to expect in the future.

Energy efficiency

As foreshadowed by the trajectory for low-energy buildings, NCC 2025 contains more significant changes for commercial (Class 3, 5-9 buildings and common areas of Class 2) energy efficiency stringency. This comes off the back of requirements for commercial buildings that were last amended in 2019 and recent significant residential stringency increases in NCC 2022.

These proposals consult on and analyse three increasing levels of stringency. The higher levels add to the common base of the previous level, stringency option 1, ‘cost-effective’ improvements to the efficiency of requirements for envelope and equipment.

Levels 2 and 3 propose adding mandatory photovoltaic panels to the majority of the building roof space. Level 3 requires additional PV (or equivalent) to compensate for or offset the presence of gas appliances used for heating or sanitary hot-water supply. This also requires additional electrical capacity and space when these appliances are retrofitted.

The highest stringency is described as ‘net-zero ready’ for ‘regulated appliances’ as these buildings still use energy, including from equipment not controlled by the NCC, and ‘ready’ because it will be years before the grid eventually decarbonises.

Electrification

In what’s likely a sign of things to come for housing in the future, the draft significantly focuses on supporting electrification at higher stringency levels.

While minor changes are proposed to the amount of supply in Class 2 buildings to accommodate electric vehicles, chargers are proposed in carparks (internal and external) for other commercial classes (except commercial 7a carparks), which are expected to bring a net cost of at least $1.5 billion.

For Class 1 housing, pre-provisioning for electric vehicles to one parking space follows changes made for Class 2 buildings in 2022.

It includes the need for a dedicated circuit and pathway terminating at a suitable outlet.

Currently, centralised hot-water systems are not an NCC DTS alternative for whole-of-home energy use in Class 2 apartment buildings. The 2025 draft proposes recognising centralised electric hot-water supply as an alternative to sanitary hot-water systems.

For Class 2 buildings, it provides an alternative to heat pumps where noise, space and rooftop PV are otherwise constrained. This is even more important in an environment where some jurisdictions are actively banning gas in new developments.

Condensation changes again

For the third time since NCC 2019, more specific condensation management provisions are proposed which will affect the cost, materials and design of dwellings.

There is an expansion in the types of materials required to be vapour permeable to all climate zones and residential building Class 3 motels, and Class 9c aged care.

One change will be felt above others for around half of all Australian buildings in cooler climates (zones 6-8): the proposal to ban direct-fix cladding solutions by mandating the use of ventilation and drained cavities for walls. Mandating dimensions of cavities in roofs and changing the required ventilation dimensions and calculation methods are, at least in part, intended to address confusion with the existing provisions.

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

Waterproofing

Waterproofing of commercial and apartment building concrete balconies, roofs, podiums, Class 7 carparks and Class 8 factories was last proposed in the NCC 2022 public comment draft. They were removed following a strong response from the industry pointing to a lack of justification from the government but now are set to return in an amended form.

Changes that will be familiar include a proposal for a consolidated Performance Requirement F1 surface water management, rising damp and external waterproofing with F3 Roof and wall cladding. There is an expansion in the situations where water must be addressed for the whole allotment, including irrigation, groundwater and sub-surface overflow from water services.

The proposals also have implications for slab design set downs and integral hobs, mandatory falls (following changes to NCC 2022 internal waterproofing) and bring with them narrow tolerances that are likely to impact materials, design and skills, leading to delay and cost increases.

Reaching a saturation point

Consultation on these proposals in NCC 2025 is also occurring when most of the industry has not yet delivered any buildings under NCC 2022 (due to state and territory transition periods under NCC 2022). This is expected to hamper the degree of comment that can be informed by practical experience and lead to a higher risk of unintended or unforeseen consequences.

In a move that’s likely to confuse some, the 2025 proposals were released on the same day as Victoria and Queensland enacted NCC 2022 residential energy efficiency and condensation changes. If approved, commencement of these changes is planned for 1 May 2025, which is either before or within weeks of other NCC 2022 implementation time frames.

HIA strongly advocates for a longer transition period for any supported changes for NCC 2025, removing this overlap and providing industry with more breathing space. Ideally, this adoption should be on 1 May 2026 or later.

How to get a copy of the changes

A copy of the draft NCC proposals and supporting documentation can be downloaded by visiting the ABCB Consultation Hub, consultation.abcb.gov.au.

HIA encourages all members to review the changes carefully. It is also important that the industry considers how it will need to respond to the changes should they proceed.

To comment on any changes, do this directly to the ABCB by 11:59pm 1 July 2024. Comments must be submitted via the ABCB’s Consultation Hub.

We are eager to hear what members think of the proposed changes.

Share your views by emailing HIA Technical services

Email us

First published on 17 June 2024.