Early stage carbon savings at Magdalen College School.
Designing the new Science Library and Partnership Building at Magdalen College School has meant working within a dense network of constraints — not just technical and environmental, but contextual, operational and spatial too.
From insurance restrictions on material choices to the need for column-free teaching spaces, and the challenges of building in a historically sensitive part of Oxford, the project has required a careful balancing of performance, embodied carbon and practicality from the outset. Through this approach, our team’s early-stage design reviews have already delivered a significant reduction in embodied carbon per floor plate — with more to come.
Image credit: Walters & Cohen
Faced with a cluster of 1970s buildings that no longer met teaching or accessibility needs, Magdalen College School appointed our project team — led by Walters & Cohen, with Price & Myers as structural engineer — to deliver much-needed new education spaces that would futureproof the Senior school site.
Extensive feasibility reviews considered the existing buildings’ fragmented floor levels, restricted access, the quality of previous extensions, and the broader, evolving requirements for teaching and building performance, and concluded that refurbishment was not a viable path.
Instead, our team set out to deliver a high-performing, low-carbon building that would meet Passivhaus standards, align with the client's long-term ambitions, and resolve a number of immediate technical challenges.
Initial structural options included steel and timber framing. While timber offered clear sustainability advantages, insurance constraints for science facilities ruled it out. Steel with composite metal deck was also assessed, but its depth conflicted with floor-to-floor height limits and service coordination. A concrete flat slab proved the most viable solution, balancing spatial efficiency, fire performance, and adaptability.
Recognising that early decisions have the most significant impact on embodied carbon, our team focused on optimising the structural layout. By repositioning columns and adjusting spans, we reduced the slab thickness from 375mm to 325mm, achieving a more efficient design.
At RIBA Stage 3, opportunities for further carbon reduction generally become more restricted. However, determined to go further, we continued close collaboration and reviews with the wider design team, and developed a reduced-carbon band beam solution. This approach concentrated the structure where it was most needed, allowing for a 200mm thick slab in key areas and resulting in a 27% reduction in embodied carbon per floor plate.
Throughout the design process, the reduction in concrete equates to the weight of five adult African elephants per classroom.
The resulting saving in embodied carbon on each floor is comparable to the amount of carbon absorbed by more than 4,500 mature trees over the course of a year.
This is the first in a series of three updates on the Magdalen College School project. With the floor structure now significantly lighter, our next focus is on how those savings can be extended to the columns, walls, shear design and substructure.
While many key decisions have already been made, the design is still evolving — and we’ll continue to challenge assumptions at every stage to unlock further reductions wherever we can.
