Assessment of thermal bridging in Victorian apartment buildings

What we are doing and why

We are supporting research by RMIT University’s School of Property, Construction and Project Management, with a research grant awarded in 2024, to conduct on-site assessment of thermal bridging in apartment buildings in Victoria.

Dr Mary Myla Andamon, Associate Professor at RMIT University’s School of Property, Construction and Project Management is leading the research

What is thermal bridging?

Thermal bridging is the unintended flow of heat between the inside and outside of a building via a conductive material.

For example, heat loss from an apartment building may occur through the steel framing in the external wall, bypassing the thermal resistance layer of insulation.

The heat transfer makes the building colder in winter and hotter in summer. These temperature variations can lead to condensation as warm moist air contacts a colder surface (internally or externally), which can lead to mould.

Mould can lead to poor air quality and negative health impacts on occupants. It may also damage the building’s structural integrity.

The work will inform design solutions and methods to reduce thermal bridging in Class 2 buildings across different construction types, which are not prescribed in the National Construction Code 2022 (NCC 2022).

The NCC prescribes methods for reducing thermal bridging for a limited range of construction types, including metal roofing and lightweight external walls. However, with the evolving complexity and variety in façade design, flooring, roofing and other envelope systems in apartment buildings, thermal bridging can also occur along certain lengths, parts and sections of the building and other commonly methods of construction where performance requirements are not prescribed in the NCC 2022.

The research is focussed on developing an interactive and evaluative tool incorporating designs and practice notes aimed at reducing thermal bridging, using thermal-bridging data from four construction system types used in Class 2 buildings in Victoria:

• timber-framed
• concrete/masonry
• lightweight steel framed
• lightweight insulated panels.

The tool will support building designers, building surveyors and builders to increase their understanding of where thermal bridging occurs and ways to to mitigate condensation.

It’s intended the findings will lead to educational materials and guidelines for industry, inform amendments to the NCC and support building practitioners in using construction methods to reduce the limit the risk of condensation.

What we have achieved so far

The research began in March 2025 and is due for completion in 2026.

It complements and extends the work we have already supported including:

• Improving building envelope resilience to moisture damage
  by The University of Sydney, supported by the BPC through a research grant awarded in 2022
• Assessment of mould growth risk in regulatory compliant 6 and 7 Star new homes in Victoria
  by the University of Tasmania, supported by the BPC through a research grant awarded in 2021.