Last month, the global construction community gathered at The Barbican Centre in London for the 2024 Council on Tall Buildings and Urban Habitat (CTBUH) International Conference to address a key question – should we continue to build new buildings, or should we focus on renewing the ones we already have? Jo Sutherland, managing director of Magenta Associates, reports from the conference.
The conference featured discussions and debates that centred on the theme ‘New or Renew: Addressing the Density Dilemma’ across nine parallel tracks, exploring the future of urban density, strategies for reducing carbon emissions and energy consumption, and the transformative potential of both new and renewed buildings in shaping the way we live, work and play.
The discourse included adaptive reuse and repositioning strategies for buildings, urban planning and social sustainability in cities, contemporary engineering and material challenges and, of course, the urgent issue of climate change and net zero. The sessions drew insights from experts representing the UK, US, Europe and Australia, among other regions, highlighting global perspectives on these crucial topics.
The case for retrofit: a duty beyond design
Across the two days of the conference, it became apparent that the environmental and social imperatives of our time demand a shift in focus from new construction to the renewal of existing structures. Retrofit was championed as the most direct path to reducing carbon emissions.
The conversation transcended architectural and engineering concerns; it touched on the moral responsibility we bear not only to the planet but to each other. With many B-grade and below office buildings standing vacant – “symbols of a bygone era”, as one panellist commented – there is both a challenge and an opportunity.
The challenge is to transform these relics of the past into vibrant, sustainable spaces that serve the needs of the present and future. The opportunity lies in addressing the pressing housing shortage by converting suitable surplus office stock into affordable housing, thereby fostering urban revitalisation and social equity.
Australia: delivering innovation
Australia’s approach to sustainable construction serves as a powerful example of how cities can confront the challenge of renewal head-on. Mike George of JLL highlighted the importance of maintaining asset viability amid the pressures of a growing population and the need to preserve built heritage. Australian cities are pioneering the reimagining of Brutalist concrete structures and adding lightweight timber extensions, showcasing a blend of ingenuity and sensitivity. These efforts are not just about preserving the past but about adapting it to meet the demands of a low-carbon future.
Another live example coming out of the ground was Atlassian Central in Sydney. Designed by BVN Architecture and SHoP Architects, the 40-storey hybrid timber tower will serve as Atlassian’s new headquarters and is set to be completed in 2027.
The project was discussed in two sessions: one focused on the structural engineering challenges of building such a tall, innovative structure on top of a heritage-listed site and adjacent to a major railway, while the other explored workplace design and Sydney’s urban regeneration over the past decade. BVN principals Catherine Skinner and Matthew Blair highlighted how this project exemplifies novel approaches to construction through the four-storey timber habitats positioned between concrete and steel mega-floors, creating naturally ventilated, experience-focused workplace neighbourhoods.
US: bridging the past and present
In the US, the emphasis on adaptive reuse is gaining traction as a key strategy for sustainability. Dana Robbins Schneider of the Empire State Realty Trust and Ian Booth of Buro Happold presented the decarbonisation efforts at the Empire State Building as a model of how historic structures can be brought into the 21st century without compromising their iconic status. The process they followed – business case development, integration and engagement, implementation, measurement and verification – illustrates a comprehensive approach to sustainability.
Gensler’s Ashley Rogow echoed this sentiment, advocating for the preservation and adaptation of existing buildings. “Adaptive reuse projects are essential for the future,” she said, stressing the intrinsic link between restoration, sustainability and the preservation of heritage. The emphasis is on creating resilient urban spaces that bridge the past and present while addressing the challenges of high-density environments.
Daniel Kaplan of FXCollaborative Architects further elaborated on the environmental costs of demolition, highlighting that two-thirds of a building’s embodied carbon is concentrated in its foundations and exterior. “Give buildings a second life,” Kaplan urged, advocating for a creative approach to the challenges these structures present. The goal is to preserve the embodied carbon while reinventing the buildings, giving them new personality and purpose.
Giving buildings a second life requires a scarce resource – people. While the focus on adaptive reuse is gaining traction, a significant challenge remains: the labour shortage. Fuquan Collins, vice president and chief diversity officer at Turner Construction, shared the urgent need for skilled workers, with Europe alone requiring two million additional workers to meet upcoming demand.
Workforce development, Collins argued, is a global priority that can address this shortage by increasing diversity in the construction sector. He emphasised the importance of creating career opportunities for individuals who might not traditionally enter the industry. In the US, for example, only 9 per cent of the construction workforce is made up of women.
Turner Construction is proactively sourcing talent from underrepresented communities, offering site tours and training programmes that expose participants to the industry. This not only helps retain skilled workers but also provides essential upskilling, laying the foundation for a more diverse and prepared workforce.
The UK: constructing second lives
Ronan Farrell, head of design at Tide Construction, shared his firm’s approach to volumetric construction, which has taken its projects to new heights, literally and figuratively. This method not only reduces waste and emissions, said Farrell, but also provides a safer, more controlled environment for workers, attracting a younger and more diverse workforce.
Critics may argue that, despite its rising popularity, volumetric modularity faces challenges, from its business model to its environmental impact. While opinions may differ on this complex debate, the industry is at least united in acknowledging the pressing need to address the ever-persistent talent gap in construction.
This side of the pond, educational initiatives like Will Academy by WILL+Partners, the workplace strategy arm of global urbanism and architecture firm Broadway Malyan, are also paving the way for a more inclusive and sustainable future in architecture. By encouraging individuals from underrepresented groups to pursue careers in the industry, these programmes ensure that the next generation of architects and builders are equipped to prioritise sustainability in every project.
Here are a few examples of how buildings have been brought back to life in the UK.
Angel Court, City of London
Originally constructed in the 1980s, Angel Court was a relic of its time, overshadowed by the advancing skyline of the City of London. In 2018, Fletcher Priest Architects refreshed this structure by retaining its existing core and basement, while incorporating 40 per cent of the original materials into the new design. This renewal not only preserved the building’s historical essence but also achieved substantial environmental savings, equivalent to preventing 215 flights from London to Chicago.
55 Old Broad Street, City of London
Another notable project by Fletcher Priest Architects is 55 Old Broad Street, originally built in 1974. The challenge lay in balancing the need to preserve the view from Tower Bridge to St. Paul’s Cathedral while adapting the building to modern standards. The architects retained the basement and lower parts of the structure, adding six new storeys and a contemporary cladding in 2008. The ongoing renewal, set to complete in 2029, aims to transform the building into a mixed-use space, integrating public consultations and workshops to inform its future as a hub for artists, galleries, retail and public health facilities, including the renovation of a Victorian-era bathhouse.
King’s Reach Tower, Southwark
John Bushell of Kohn Pedersen Fox Associates spearheaded the rehabilitation of King’s Reach Tower, a 1970s structure that had long been out of favour. By extending the core and transforming the precinct into a mixed-use development with residential, office and retail spaces, the project has become a cornerstone of the South Bank’s urban regeneration.
New City College, Tower Hamlets
Skidmore Owings & Merrill’s Sukriye Robinson tackled the renewal of New City College in Tower Hamlets, one of England’s most socially deprived areas. The project required a deep understanding of the site’s physical constraints and the needs of the community. By relocating residential units and creating spaces that promote flexibility, movement, safety and privacy, the architects demonstrated that renewal projects demand a holistic approach, even when the temptation to demolish might arise.
Minerva House, Southwark
Daniel Pitkin from Great Portland Estates provided insights into the transformation of Minerva House, an oppressive and unwelcoming 1981 structure, complete with moat. The 2023 renewal project focused on maximising shareholder value by creating best-in-class office space while fostering good community relations. Remarkably, 70 per cent of the building was reused, including the floor slabs, which were extended to increase the floor area. The project also involved the salvage and reuse of 20,000 carpet tiles. Bonuses for the project team were tied directly to ESG targets, emphasising the critical role of sustainability in modern construction.
These examples illustrate how the renewal of existing structures can not only preserve architectural heritage but also drive environmental, social, and economic benefits.
Renew versus new
The overwhelming consensus was clear. Retrofit, rather than new-build, is the most effective strategy for achieving decarbonisation, promoting social equity, and ensuring sustainable urban development.
The discussions at the CTBUH 2024 conference leave little doubt that the future of urban development lies in renewal rather than starting from scratch. The embodied carbon in existing structures, the principles of the circular economy, and the need to reduce our environmental impact all point to the same conclusion: we must embrace the challenges of renewing our built environment with creativity and purpose.
The conference highlighted that while new construction has its place, the most sustainable path forward is to adapt and renew what we already have, ensuring that our cities are not just fit for purpose, but fit for the future.
