55 Southbank Boulevard

With the built environment playing a significant role in global carbon emissions, building with timber presents a revolutionary solution to solving the climate crisis with great potential for carbon absorption. The existing 8-storey building was originally designed to support an additional five floors of concrete framed structure, which would not be sufficient to house a hotel which was the owner’s desired use of the building. Challenges inherent to the adaptive reuse and partial demolition, along with the fact that few contractors had CLT experience, each had to be overcome with minimal impact on the existing commercial office tenants during construction.

The development’s innovative use of cross-laminated timber presented a more sustainable and efficient approach to increasing density, providing 13,000 square metres of new floor space and 220 new hotel rooms. Significantly lighter than concrete, no other material aside from timber would have allowed the addition of ten levels to be built, with added benefits including reduced carbon emissions, lower transport costs and time savings from off-site manufacturing. Building a 10-level, 32-metre extension on top of an existing eight-storey concrete office building would raise the mixed-use development’s height to 71.56 metres – resulting in the world’s tallest engineered timber extension.

Before the apartment hotel opened in November 2022, it had already set a new green precedent. The use of approximately 1,730 tonnes of CLT absorbed nearly 2,800 tonnes of carbon dioxide from the atmosphere, converting the building into a carbon sink in the process. In addition to reducing carbon emissions, building with timber promotes wellbeing, connection to nature and humanising high-density environments for people to live, work and play. This globally significant approach to adaptive reuse is one that can be deployed in any number of global contexts and paves the way for a more sustainable future.

Capitalising on the premier corner position and celebrating the building’s new height is a large, recessed balcony where guests can take in views of the nearby parkland and city skyline. Rather than simply repeat the prevailing spandrel banding, the addition responds with a series of recesses to deliver an elegant and dynamic, complementary façade expression. The added levels also amplify the curved architecture of the existing building with a more contemporary articulation.