NCC Version:
2019 Volume Two - Amendment One
Area of NCC Requirements:
Section 3.4.1.2 – Subfloor Ventilation
Performance Requirement P2.2.3 – Rising Damp
Problem:
The proposed residence does not meet the Deemed-to-Satisfy (DTS) provisions for subfloor ventilation, which are required to prevent rising damp. The lack of adequate natural ventilation in the subfloor space can lead to moisture accumulation, creating conditions that promote timber rot, fungal growth, and potential termite activity. The subfloor clearance and ventilation openings do not conform to the NCC standards therefore a Performance Solution is necessary to demonstrate compliance.
Solution:
Performance Solutions Australia implemented a mechanical ventilation system as an alternative to natural crossflow ventilation. The solution includes a VKM 100mm Inline Fan (270m³/hour), ducted airflow management, and compliance with BCA subfloor ventilation and clearance requirements. Expert analysis confirms it meets or exceeds DTS compliance.
Finalised Report:
The evaluation confirmed that the mechanical ventilation system effectively mitigates rising damp and meets Performance Requirement P2.2.3. By maintaining continuous airflow and moisture control, the Performance Solution ensures the subfloor environment remains dry and structurally sound. The report concludes that the proposed design achieves compliance and satisfies the necessary acceptance criteria.