The Michael Kirby Building is the new home of the Macquarie University Law School and Department of Philosophy, located at the university's Wallumattagal Campus near North Ryde. The existing 1985 double storey administration concrete structure was reused and transformed into the new hybrid timber-concrete four-storey building, with a total floor area of approximately 8,500 m².
The lightweight nature of mass timber was critical to the project's feasibility. A concrete or steel structure would have been too heavy as the Epping to Chatswood rail corridor runs directly below the building. The existing concrete was retained to the first floor, with three levels of mass timber constructed above. This added much needed extra floor space to the building and enclosed the central courtyard to form a new atrium.
Sustainability drove both the material choice and the adaptive reuse approach. Timber was chosen primarily for its lightweight nature, allowing two storeys of demolished concrete frame to be replaced by three storeys of lighter timber. This greatly increased capacity while only slight additions to the foundation were required. The exposed CLT structure reduced carbon emissions while the sawtooth roofing with south-facing roof maximises natural light while minimizing solar heat gain. The building achieved a 5-Star Green Star rating.
