The National Construction Code (NCC) 2025 is set to reshape the way waterproofing is designed, specified and installed - and it's time to start preparing now.
The changes are among the most significant in years, with the potential to affect everything from early-stage design and documentation to established practices on-site.
What's changing?
NCC 2025 introduces significant changes to waterproofing requirements, expanding both the scope of what constitutes “water” and the obligations placed on specifiers, builders and waterproofing applicators. The changes consolidate key Performance Requirements, extend waterproofing provisions to Class 7 and 8 buildings, and introduce a more rigorous, evidence-based approach to below-ground waterproofing.
They also tighten several technical detailing requirements, including minimum falls, step-downs, hob construction and membrane installation, while removing the long-standing practice of installing screeds over waterproofing membranes.
What's the timeline across each state?
The NCC is given legal effect through individual state and territory legislation. This means NCC 2025 is taking effect at different times:
- The ACT, Tasmania, Victoria and Western Australia adopted NCC 2025 from 1 May 2026, with 12-month transition arrangements in the ACT and Western Australia.
- New South Wales, Queensland and South Australia are scheduled to adopt it from 1 May 2027.
- The Northern Territory has not adopted the new edition.
Fosroc ANZ's national footprint and proven experience supporting projects across every state means we are well placed to help clients prepare for NCC 2025 as it rolls out across each jurisdiction.
"In fact, we're already helping many clients plan for their state's timeline," says Product Segment Specialist for Waterproofing and Sealants, Colin Picton.
Changes to definitions, requirements and building classes
Section F covers the waterproofing component of the NCC, and NCC 2025 introduces several changes to how water ingress is addressed:
A broader definition of “water”
NCC 2025 broadens the meaning of “water” for the purposes of the waterproofing. The definition now encompasses surface water, sub-surface water, rainwater, stormwater, rising damp, overflow from water services and surface water seepage. This reflects a more comprehensive approach to managing the different ways water can enter or affect a building.
Performance Requirements consolidated
The previous Performance Requirements F1P1–F1P4 and F3P1 are consolidated into two requirements: F1P1 and F1P2. This brings requirements relating to water ingress, weatherproofing, rising damp and groundwater into a more unified framework.
The scope of these requirements has also been expanded. Class 7 and Class 8 buildings are no longer exempt, meaning these building classes must now satisfy the relevant waterproofing Performance Requirements under NCC 2025.
Changes to below-ground waterproofing
For specifiers in particular, one of the most significant changes is below ground. Under NCC 2025, there is no Deemed-to-Satisfy shortcut for below-ground waterproofing - a documented Performance Solution is mandatory.
That solution must also be evidence-backed. Project teams will need to draw on appropriate suitability data, testing or expert judgement to demonstrate that the proposed waterproofing solution will perform as required.
For specifiers, this places greater emphasis on the technical evidence behind the products and systems being nominated - and having that evidence readily available to support the Performance Solution.
"Fosroc invests heavily in independent product testing, ongoing certification and transparent access to supporting documentation. This helps specifiers quickly find the evidence they need to support a Performance Solution," explains Colin.
All Fosroc Test Certificates are published on our website and are easily searchable by product or solution.
Changes to technical design requirements and screed installation
Applicators will also see some important changes to on-site practice:
Tighter design requirements
NCC 2025 introduces tighter design requirements, including minimum 1:80 falls, 70 mm step-downs and monolithic hobs of at least 70 mm. Membranes complying with AS 4654.1 and AS 4654.2 must be applied directly to the structural substrate.
Fosroc ANZ offers a range of waterproofing systems featuring products that have been independently tested to AS/NZS 4654, including:
Changes to screed installation
Another significant change relates to screeds: screeds can no longer be installed over the waterproofing membrane. This reshapes a long-established installation sequence on many projects. Substrate preparation, falls, drainage, detailing and membrane placement will need to be resolved before waterproofing begins.
"For both designers and applicators, this change is significant. It means waterproofing will need to be considered earlier and in greater detail rather than being resolved later onsite," says Colin.
What NCC 2025 waterproofing changes mean for project teams
"NCC 2025 raises the bar on evidence, direct-to-substrate application and allows for fewer exemptions," says Colin. "Below-ground waterproofing Performance Solutions will need to be properly documented and supported by suitable technical data, testing or expert judgement."
"For applicators, the impact will be more tangible on-site. Requirements around substrates, falls, drainage, joints, hobs and membrane placement mean some familiar waterproofing methods and installation sequences will need to change."
Fosroc waterproofing systems in action
As NCC 2025 changes roll out across Australia, specifiers, applicators, project managers and asset owners can be confident in Fosroc ANZ's proven waterproofing product and system performance and compliance. Here are just a few examples of Fosroc waterproofing systems in action across the nation:
- Bluescope Steel - above ground waterproofing to protect critical infrastructure
- Elizabeth Bay apartments - remedial works to tackle roof leaks in an apartment building
- Hillcrest Christian College - a comprehensive waterproofing solution for a major education facility
Get ahead of the change
Fosroc ANZ's product and technical experts can help you navigate the waterproofing changes to NCC 2025 prepare for its adoption in your state: