NCC 2022 – Ventilation in Steel Roofing

COLORBOND steel Woodland Grey roof in a corrugated profile

Approaches to satisfy NCC 2022 ventilation requirements for residential roofs in Climate Zones 6, 7 and 8.

To help support the construction industry, The Australian Steel Institute (ASI) and the National Association of Steel-framed Housing (NASH) have jointly developed a series of resources exploring ways to meet the revised National Construction Code (NCC 2022) and providing general best practice information.

The Ventilation in Steel Roofing topic includes a PDF download and video presentation. It provides practical guidance and examples of ventilation approaches to meet the new requirements for the cooler Climate Zones 6, 7 and 8 to mitigate the risk of condensation and moisture accumulation in the roof space. The topic covers:

  • The NCC 2022 Deemed-to-Satisfy (DtS) requirements for roof ventilation (based on roof pitch and roof design)
  • Demonstrates how common steel roofing profiles can provide passive ventilation into the roof space
  • Includes approaches to incorporate ventilation into steel roofing systems at the high and low level including:
    • membranes being terminated at the ridge to leave an opening for ventilation between a corrugated roof sheet and the ridge cap
    • ventilation devices (such as ridge vents) installed at the ridge
    • installation of a mechanical vent or smart vent at the ridge
    • ventilation accessories integrated at the fascia to create a ventilation path
    • ventilation devices installed under the sarking
    • soffit vents
  • Provides examples and simple-to-understand drawings for typical residential applications

Advancements in energy-efficient buildings may increase the risk of condensation issues in roofs and walls. High thermal performance is driving increased insulation levels and increased air tightness and if not appropriately managed, the accumulation of condensation can become problematic. As a result, additional roof space ventilation requirements were introduced in NCC 2022 and apply to both steel and tiled roof types, in both standard pitch truss roofs and skillion cathedral roof types.

The information presented in this topic will interest a wide range of construction industry stakeholders including, designers, installers, builders, developers, and certifiers. Condensation management is an ongoing focus area of building design and performance. It is recommended that designers and construction professionals also refer to the “Condensation Management for Steel Roofing” topic for further guidance.

Further information:


Published Date

January 2024

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