In Sydney’s Circular Quay, 3XN Architects have redefined sustainable architecture by completing the world’s first upcycled skyscraper, which maintained up tp 70% of the previous building’s materials. the team retained up to 95 % of the original core and 65 % of beams, slabs, and columns, saving an estimated 12,000 tonnes of embodied carbon.The Quay Quarter Tower (QTT) is a radical example of circular design in architecture, demonstrating that the age of demolition may be giving way to transformative reuse.
Rising 216 metres over 54 stories, QQT’s form is composed of five stacked, twisted blocks each cantilevered, shifting, and rotated to maximise views of the harbour, Opera House, and bridge. Its sculptural façade is tuned to solar orientation to reduce heat gain. Inside, double-deck lifts reduce core mass and increase lettable area. The design also incorporates split-level sky lobbies, terraced communal zones, and landscaped terraces and vertical “streets” in the sky. Landscaping bridges and external terraces connect the building to the public realm at various levels, reinforcing its civic presence.
QTT has been nominated for the prestigious 2025 Earthshot Prize, underlining how sustainable building practices. “The demolition cycle is one of the greatest threats to our global climate goals. Quay Quarter Tower proves that transformation at significant scale is possible and, critically, commercially viable. We extended the life of a building by decades, halved its carbon impact, and created a more engaging workplace for thousands of people.
This recognition from The Earthshot Prize reinforces that regeneration must replace destruction as the new standard. We hope that our approach can help redefine urban development, offering a blueprint to meet low-carbon ambitions as our cities worldwide continue to grow” Fred HoltDesign Lead, Partner 3XN, Director 3XN Australia
