Mark Dewsbury, M.AIRAH

University of Tasmania
For better or for worse – interstitial condensation, 2019 to 2022

The 2019 National Construction Code (NCC) includes requirements for condensation minimisation, combined with greater building air-sealing expectations. The new condensation provisions apply to NCC climate zones 6, 7 and 8. 

Although the new provisions include vapour-permeable membranes, they don’t require a vapour cavity. This contrasts with regulations in most developed countries, which require a vapour control layer and vapour cavity. Inadvertently, the air-sealing provisions may see a significant use of vapour- impermeable membranes. This presentation poses the question: Will the application of the 2019 NCC lead to increases in interstitial condensation and mould in new buildings? 

About Dewsbury:
Dewsbury is passionate about the pathway to zero energy and sustainable buildings. His professional experience includes more than 30 years within the public and private sectors. As a senior lecturer and degrees coordinator within architecture and design at the University of Tasmania, his focus is on methods of designing and building to improve construction, thermal performance and indoor environmental qualities while minimising condensation risk in buildings.

Dewsbury’s research provides input for NatHERS, building simulation programs, and the NCC. His research collaborators include industry partners, CSIRO, and state/federal government agencies.