NCC Version:
2022, Volume Two – Building Code of Australia (BCA) Class 1 and 10 buildings.
Area of NCC Requirements:
Section H: Damp and Weatherproofing
- Part H2: Surface rising damp and external waterproofing
- Performance Requirements:
- H2P1: Rainwater management
- H2P2: Weatherproofing
- Functional Statement:
- H2F2: Weatherproofing and dampness
Problem:
The problem arises from the proposed zero-threshold floor design at the outdoor pool area, which does not meet the National Construction Code’s (NCC) Deemed-to-Satisfy provisions requiring a 100mm step-down to prevent water ingress. This deviation increases the risk of rain or surface water entering the building, potentially causing dampness, structural damage, or health hazards due to moisture accumulation.
Solution:
To address the non-compliant zero-threshold design, a Performance Solution was developed using the Stormtech 38G90 grated drain system. This custom drainage setup effectively manages surface water by providing high-capacity drainage at the threshold, preventing water ingress without the need for the standard 100mm set-down. The solution was assessed using expert judgement, ensuring it meets the functional intent of the NCC’s weatherproofing and damp-proofing requirements.
Finalised Report:
The final report confirms that the proposed Stormtech drainage system complies with NCC 2022 Performance Requirements H2P1 and H2P2. Through documented expert evaluation, performance testing, and installation criteria, the solution is shown to effectively manage water and prevent damp-related issues. The system is accepted as a compliant alternative to the Deemed-to-Satisfy provisions, satisfying all necessary conditions for approval.