3XN’s Quay Quarter Tower Shows How Upcycling Buildings Can Cut Carbon and Extend Urban Assets

When Sydney’s AMP Centre began approaching the end of its useful commercial life, the conventional response would have been straightforward: demolish the tower and replace it with a new high-rise. Instead, Danish architecture firm 3XN and its project partners chose a more complex route. They transformed the 1970s office building into Quay Quarter Tower, a major adaptive reuse project now being cited as a benchmark for low-carbon urban redevelopment.

The project, discussed by Fred Holt, partner at 3XN Architects and director at 3XN Australia, in a recent BusinessGreen interview, has gained international attention because of its scale and carbon implications. Quay Quarter Tower has been described as the world’s first fully upcycled skyscraper and was named a finalist for The Earthshot Prize in 2025 under the “Build a Waste-free World” category.

Retaining the Carbon Already in the Building

At the heart of the project is a simple but technically demanding principle: reuse as much of the existing building as possible. Rather than clearing the site and beginning again, the project team retained around 65% of the original structure and most of the building’s core. This included existing beams, columns, slabs, and structural walls.

By keeping these high-carbon components in place, the redevelopment avoided more than 12,000 tonnes of embodied carbon, according to project information published by 3XN, The Earthshot Prize, and the Green Building Council of Australia.

The building’s transformation is significant because embodied carbon is becoming a central issue for the real estate and construction sectors. Operational emissions from buildings, such as energy used for heating, cooling, lighting, and equipment, have long been a focus of sustainability strategies. However, the carbon emitted during material production, transport, construction, demolition, and replacement is increasingly difficult to ignore.

Concrete and steel, in particular, carry substantial upfront carbon footprints. For large commercial towers, demolishing and rebuilding can lock in a major emissions burden before the building is even occupied.

A New Model for Office Redevelopment

Quay Quarter Tower demonstrates an alternative path. The original AMP Centre, located at 50 Bridge Street near Sydney Harbour, was no longer well suited to modern office requirements. Its services were ageing, its layout was constrained, and its floorplates did not meet contemporary tenant expectations. But the building still contained valuable structural material.

3XN’s design worked with the existing tower rather than against it, adding new floor space, reshaping the building’s form, and creating a series of stacked “vertical villages” arranged around atria.

The result is not a cosmetic refurbishment. The project substantially increased the usable office area, with The Earthshot Prize noting that space was expanded from about 45,000 square metres to 102,000 square metres, while capacity rose from around 4,500 to 9,000 people.

The redesign also introduced new glazing, shading, open-plan workspaces, improved views, and upgraded building systems. In sustainability terms, the project paired material reuse with improved operational performance, including strong green building credentials.

Green Building Credentials and Operational Performance

The Green Building Council of Australia has highlighted Quay Quarter Tower as a 6 Star Green Star rated project, describing it as an example of “World Leadership” in sustainable design and construction.

The building has also been associated with WELL, Green Star Interiors, and NABERS Office Energy ratings, underscoring the importance of combining circular construction with occupant wellbeing and energy performance.

This distinction matters because adaptive reuse alone does not automatically create a low-carbon asset. A retained structure still needs to perform efficiently in operation. In Quay Quarter Tower’s case, the reuse of existing materials was paired with upgraded services, improved façade design, modern workplace layouts, and higher environmental performance standards.

Why Adaptive Reuse Matters for Real Estate

For developers and asset owners, the commercial implications may be as important as the environmental ones. Adaptive reuse is often treated as a compromise, particularly for large office towers, where older structures may be seen as difficult to modernise. Quay Quarter Tower challenges that assumption.

According to World Green Building Council case study material, reuse of existing resources helped generate estimated economic savings and reduce construction time. The project also avoided the disruption, waste, and carbon impacts associated with full demolition.

For real estate investors, this approach is increasingly relevant. Building owners are under growing pressure to manage climate-related risks, improve energy performance, meet tenant expectations, and reduce lifecycle emissions. In dense urban markets, retaining and upgrading existing structures may become an important strategy for protecting asset value while reducing carbon exposure.

The Technical Challenge of Reusing a High-Rise

The technical complexity should not be underestimated. Reusing a high-rise structure requires detailed knowledge of the existing building, structural testing, digital modelling, engineering coordination, and close collaboration between architects, developers, engineers, contractors, and regulators.

In Quay Quarter Tower’s case, the team had to integrate old and new structures, assess the capacity of existing elements, monitor structural performance during construction, and design additions that could expand the building without overloading the retained frame.

This level of coordination makes adaptive reuse more demanding than a standard refurbishment. However, it also shows that older commercial towers can contain significant hidden value if their structure is properly assessed and incorporated into a new design.

Lessons for Cities with Ageing Building Stock

That complexity is one reason the project is relevant beyond Sydney. Many cities face a growing stock of ageing office towers built in the second half of the 20th century. Some are inefficient by modern standards, while others are struggling with changing occupier demand, hybrid working patterns, or regulatory pressure to improve energy performance.

The default response of demolition and redevelopment may become harder to justify as carbon reporting, building performance standards, and circular economy policies strengthen.

For companies with net-zero commitments, projects like Quay Quarter Tower raise practical questions. Real estate portfolios are increasingly scrutinised not only for operational energy use, but also for lifecycle emissions. Tenants may seek lower-carbon office space as part of their Scope 3 strategies. Investors may ask whether redevelopment plans properly account for embodied carbon risk. Local authorities may also increasingly prefer reuse strategies where they can preserve urban density while reducing waste.

Not Every Building Can Be Saved, but Demolition Should Be Questioned

The project does not mean every old tower can or should be retained. Some buildings may have structural, safety, contamination, or design constraints that limit reuse. However, Quay Quarter Tower shows that demolition should not be treated as the automatic first option.

For high-value urban sites, early-stage feasibility studies can compare demolition and rebuild scenarios against adaptive reuse options, using whole-life carbon analysis, cost modelling, planning considerations, and market demand.

This is especially important for buildings with large concrete and steel structures, where a substantial share of lifecycle emissions is already embedded in the existing asset. Reusing that material can avoid new emissions while reducing construction waste and preserving urban resources.

A Circular Design Case Study at Skyscraper Scale

The broader lesson is that low-carbon construction is not only about new materials or future technologies. It is also about recognising the carbon already embedded in existing buildings. In that sense, the “greenest” building may not always be a new net-zero tower, but an old one carefully reworked for another generation of use.

Quay Quarter Tower has turned an ageing commercial asset into a high-profile example of circular design at skyscraper scale. As cities look for ways to grow while cutting emissions, its relevance is likely to extend far beyond Sydney.

Source: www.businessgreen.com