Airtightness and thermal bridging in buildings

The NCC 2022 was published on 1 October 2022, via NCC online, and is now in force. States and territories adopted the NCC 2022 on 1 May 2023. Transition arrangements apply for some requirements, see here for more information.

Cover image. Monash University Gillies Hall, Peninsula Campus, by JCB (Image: Peter Clarke). All buildings should provide a durable enclosure, thermally comfortable interior, good indoor air quality and energy-efficient operation. These measures can largely be met through an airtight building fabric with adequate controlled ventilation and continuous insulation to address thermal bridging. This fundamental approach represents a step-change in how most Australian buildings – of all types – are currently designed and constructed.

This note provides strategies to reduce thermal bridging within a building's structure and achieve a high-quality airtight envelope. The note also considers the critical synergies between airtightness and effective ventilation for optimal indoor environment quality.

Key words: airtightness, condensation, controlled ventilation, insulation, thermal bridging.