Sydney’s Atlassian Central has reached its full structural height, becoming the world’s tallest hybrid timber tower and setting a new benchmark for sustainable, technology-driven commercial development.

The 39-storey building now stands at more than 180 metres following the completion of its final structural level, known in construction as "topping out". The project surpasses the previous record holder, the 25-storey Ascent tower in Milwaukee, USA, by around 100 metres.

*At the topping out: (L-R) Mike Cannon-Brookes, Ross Du Vernet, Clover Moore, Daniel Mookhey, Marco Rossi, Daisuke Iwata*

Designed around a hybrid structural system, the tower combines mass timber with steel and concrete to balance sustainability with structural performance. Timber significantly reduces the building’s overall weight and embodied carbon, while steel and concrete provide the strength and stability required for a high-rise commercial building.

The project also reimagines the modern workplace through a four-storey habitat that integrates natural materials, daylight, fresh air and collaborative workspaces. The building is targeting a 50% reduction in upfront embodied carbon compared to a conventional premium commercial office tower, alongside a 50% improvement in operational energy efficiency relative to a standard 5 Star NABERS base building.

“Reaching the topping out of Atlassian Central is a truly momentous occasion,” says Andreia Teixeira, Associate Principal, SHoP.

“It’s particularly rewarding to begin experiencing the spatial qualities of a high-rise that reimagines a natural habitat within an urban tower – connecting people to each other, nature and to the city around them. We’re excited by how this concept sets a new benchmark for sustainability, where timber, landscape, and natural ventilation come together to shape a more holistic work-life experience and inspire future innovation,” Teixeira adds.

Achieving this milestone has been both demanding and rewarding, only made possible through constant design innovation and collaboration across the whole project team, says BVN Principal Peter Titmuss.

“Hybrid mass timber has done more than reduce embodied carbon, it has fundamentally shaped how tower buildings can be delivered, enabling prefabrication, dry construction and a faster, lighter vertical build. As a prototype for mass timber towers of the future, this is a moment of global significance.”

The topping out reflects a project defined by long-term thinking and a willingness to challenge convention, observes Dexus Group CEO & Managing Director Ross Du Vernet.

“We set out to prove that large-scale commercial buildings can be delivered differently. This project has been pioneering in every sense, demonstrating how we can reduce carbon, support wellbeing, and create a workplace built for the future – while still meeting the rigorous expectations of global tenants and investors.”

Atlassian CEO and Co-Founder Mike Cannon-Brookes says the building has been conceived as a platform for the future of work.

“Atlassian Central is what happens when you apply technology thinking to commercial real estate. It’s not just a smart building with a few dashboards bolted on. It's the most technologically advanced building in Australia – operating like a software platform, sensing, learning, and adapting in real time. We built it for a future of work that will keep being reinvented by AI, by new ways of collaborating, and by technologies we haven't even imagined yet.”

Delivering the project required complex digital engineering and construction sequencing. Australian contractor Built, in a joint venture with Obayashi Corporation, has led the construction, coordinating the integration of mass timber, steel and concrete into one of the country's most technically ambitious commercial developments.

“Combining a mass timber structure with a 39-storey commercial tower required new ways of designing and building, with our team setting a new benchmark. Years of investment in innovative construction methods, advanced modelling and in-house capability enabled us to virtually build and sequence one of Australia's most complex projects long before work began on site,” says Built Executive Chairman, Group CEO and Founder Marco Rossi.

The project remains on schedule for practical completion by the end of the year.

Atlassian Central is co-owned by Dexus and Atlassian, developed by Dexus, and delivered by Built in joint venture with Obayashi Corporation.

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Architecture News & Editorial Desk

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