Kelsey Stewart, from Pilbrow & Partners, discusses that while tall buildings pose challenges, innovative designs and low-carbon materials can make buildings more efficient.

While tall buildings typically pose challenges, particularly when considering the impacts of embodied carbon, there still exists a compelling argument in favour of their efficient land use and optimised development in well-connected locations. The focal point therefore shifts from questioning the viability of building vertically to exploring innovative solutions that enhance existing construction methods and materials. In our commitment to environmental sustainability, Pilbrow & Partners (P&P) adopts a holistic perspective in addressing carbon reduction. We recognise the importance of employing multiple strategies to minimise our carbon footprint. 

By embracing a range of strategies, including efficient design, low-carbon materials, the exploration of emerging products, and the integration of innovative systems, we are working to actively shape the landscape of environmentally responsible construction. Central to mitigating the carbon footprint is reevaluating the prevalent use of concrete and other carbon-intensive materials. Acknowledging the necessity of a paradigm shift, we are actively implementing these strategies to diminish concrete usage, thereby reducing the carbon impact of tall building designs. 

P&P’s approach to reducing concrete usage in tall buildings has involved a critical analysis of structural efficiency within conventional concrete design. For instance, designing a new tall building in London provided our office with an opportunity to explore a unique tripod arrangement- three wings of accommodation around a central core. Early testing completed by structural engineers confirmed that the proposed tripod configuration requires approximately one-quarter of the concrete required in a conventional rectangular central core floor plate. When tested alongside its conventional counterpart, the tripod core, distinguished by its natural stiffness, allowed for a substantial material reduction, resulting in approximately 70 percent reduction in carbon. Beyond reducing concrete usage, the design also enhanced the overall residential quality, providing well-lit corridors, community-like clusters, a higher proportion of dual aspect, and generous amenity spaces. Recognising the connection between good quality housing and personal well-being, the design strives to encourage sustainable communities and hopefully a longer lifespan for the proposed tall building.   

Shifting focus to a project at a later stage under construction, EDGE London Bridge employs a hybrid solution to reduce concrete usage. With post-tensioned concrete chosen for its efficiency, and responsibly sourced timber infill framing for its low-carbon properties, the design reduces embodied carbon in both superstructure and substructure. Timber, recognised for its carbon sequestering abilities, was introduced to allow for adaptable space where the floor structure can be partially removed to provide links between floors. This extends the life of the building, providing flexibility to accommodate occupiers' evolving needs.

 

While not all structures can be classified as tall buildings, minimising the carbon footprint of all designs remains a central focus. Collaboratively with a team of skilled engineers, we are currently exploring the application of the traditional arch form to establish a system of compressive vaults. This has the potential to yield a one-third reduction in overall concrete usage compared with that of a conventional concrete frame. Furthermore, the team has adapted the system to use cut pieces of existing concrete bound together to form the vaults, significantly reducing the carbon footprint. Although the design is still in its early stages, this exciting development shows promise as an upcoming method for concrete reuse and potential for future use in tall buildings. 

 

In pursuit of sustainable infrastructure that recognises and responds to the diverse challenges of our time, it is imperative for architecture to address the reduction of carbon as a pivotal component in fostering a more comprehensive vision of sustainability. As demonstrated through each project, P&P is committed to reimagining typical construction methods and materials, integrating them into the everyday design of tall buildings, and contributing to a better tomorrow. Through a holistic approach, we continue to strive towards a liveable, equitable, and flourishing future.