Condensation Management Changes in the NCC from 1 May 2019

Approx read time: 2 minutes

Better insulated and sealed homes perform well in cold climates but they need to release the water vapour accumulated inside as a result of everyday activities like heating, cooking & washing. Vapour permeable wraps allow the release of water vapour from inside the home while preventing the entry of external water and air.

A common misconception is that the original breather foil is compliant behind lightweight cladding, which isn’t the case as the product is not vapour permeable. Lately we have been seeing quite a few enquiries come through about this issue.

WHY HAS THE NCC MADE THIS CHANGE?

As the BCA classifies the Hunter region as climate zone ‘5 & 6 and it is important that condensation is managed correctly to avoid expensive rectification work. Enviroseal ProctorWrap and HardieWrap (stocked by NHS) are both highly vapour permeable and allows water vapour to escape the home making it the ideal way to manage condensation risk.

NCC changes starting 1st May 2019

On the 1st of May 2019, the National Construction Code will introduce a new section titled ‘Condensation Management’ which includes an important change to the selection of wall wrap.

The change will effect all Building Permits approved after the 1st of May 2019. All Building Permits approved using NCC2016 will not be affected by this change, and may use the wall wrap included in the original specification.

The NCC changes to Volume 1 Part F6.2 and Volume 2 Part 3.8.7.2 will state that if a wall wrap is installed onto an external wall frame in BCA Climate Zone 6, 7 & 8, it is required to be vapour permeable. This change is mandatory for brick veneer and lightweight clad construction.

In summary, any Building Permits for Class 1, 2 and 4 buildings approved after the 1st of May 2019 that include a pliable building membrane on the external wall frame, that membrane must be vapour permeable in climate zones 6/7/8.

A detailed summary of the affected municipalities are shown by BCA Climate Zone here…

The main change to these zones for the Hunter Region, is that Dungog is now a Zone 5 (from a Zone 6)

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If you have any questions about your particular application, please dont hesitate to give our friendly team a call to discuss – 4979 0000.