NCC Condensation & Ventilation: What You Need to Know

NCC Condensation & Ventilation: What You Need to Know

As most builders are aware, effective from May 1st, 2024, the National Construction Code (NCC) has introduced significant changes regarding condensation and ventilation. While these changes may not be as noticeable as changes related to energy efficiency or liveability, they are nonetheless crucial for builders to implement accordingly.

What are the NCC Condensation & Ventilation Key Takeaways?

Wall Sarking

One of the key changes relates to wall sarking requirements. The NCC now mandates the use of vapour permeable wall sarking equivalent to Class 3 or Class 4 membranes, depending on the climate zone.

• Climate zones 4 and 5 will need a Class 3 vapour permeable wrap
• Climate zones 6-8 will need a Class 4 vapour permeable wrap.

Alongside the use of Class 3 or 4 vapour permeable wall sarking, changes to the installation of sarking have also been introduced which includes a drainage cavity. These changes aim to improve the overall performance of building envelopes, particularly in areas prone to high humidity or moisture ingress.

Ventilating Roof Spaces

Roof space ventilation requirements have also been updated within the National Construction Code. Builders must now provide adequate air spaces for roofs with additional roof space ventilation. This can be achieved through the installation of whirlybirds, ridge vents, or eave vents. These changes are intended to enhance the overall ventilation and thermal performance of roofs, reducing the risk of condensation and moisture buildup.

Exhaust Systems

Exhaust system requirements have also been revised under the new NCC. Minimum flow rates for exhaust fans have been specified, ensuring that these fans are capable of effectively removing moisture from indoor spaces. Rangehoods and exhaust fans must now be ducted to the outside, and recirculating rangehoods are no longer permitted. Bathrooms that are not naturally ventilated must have exhaust fans equipped with a 10-minute run-off timer, further improving indoor air quality and reducing the risk of condensation.

Additional provisions have been made for ventilation in laundries and bathrooms containing a dryer. These spaces must be adequately ventilated to prevent moisture buildup, which can lead to mould growth and other issues.

Solutions for the Industry

To prevent condensation, moisture build-up and mould growth within the home, there are a wide range of products that can help.

Innovative products from suppliers such as Click IN Systems™ offer window seals that work with their Click IN Window System to prevent leakage of air from the home. GI Building Sciences range of vapour permeable membranes are not only a recycled, environmentally friendly product, the range improves the thermal quality of the home. Alpine Ventilation range are a suitable solution for roof vents, eave vents, fans and ducting systems. For more product to help meet the new NCC changes, explore our product range online or speak to one of our friendly staff today.

More Information on NCC Solutions

Bowens are facilitating an NCC Workshop Series from May to July 2024, to help builders incorporate product-based solutions into their designs and new builds. Find more information on our NCC Workshop Series or to attend a workshop near you, explore our NCC page.

For more comprehensive information on the NCC changes, builders are encouraged to visit the HIA website and speak to a representative from your state who can provide guidance on how to navigate these changes effectively.