Miriam Owen, Associate Director at Edgars shares lessons learnt for those managing emergency works in heritage buildings.

St Catherine’s College in Oxford is a masterpiece of modernist architecture. Designed by the renowned Danish architect Arne Jacobsen, the site consists of nine Grade I listed buildings set within a Grade I Registered Historic Park and Garden. It is a site of exceptional national and international heritage.

In 2023, the College faced a crisis. Reinforced Autoclaved Aerated Concrete (RAAC) was found in the roofs of the original Jacobsen buildings. This discovery posed a significant safety risk and required immediate action. The challenge was to carry out urgent and large-scale works on a Grade I listed icon without compromising its unique heritage value. When the Edgars team took on this project, they ensured that the focus was centred on the safety and preservation of the heritage buildings. The project that followed offers valuable lessons for any professional navigating emergency works on a significant heritage asset.

A transparent and collaborative approach

The most important lesson was the value of transparent communication. Success depended not just on finding the right technical fix, but on bringing everyone on the journey. The Edgars team adopted an integrated and collaborative approach from day one, combining their planning and heritage expertise. This allowed them to address technical problems and heritage concerns at the same time, rather than one after the other. Early and frequent engagement with key stakeholders including Oxford City Council, Historic England and the Twentieth Century Society was vital. Preliminary conversations, early information sharing and a collaborative approach to key decision making helped to build trust. The design challenges and policy issues were tackled proactively before they became planning delays. This collaborative process not only built trust but also ensured that when challenges arose, they could be resolved with speed and mutual understanding.

Strategic phasing for heritage assets

A strategic and phased planning approach was also critical. The project was split into two phases to manage the complexity and timescale. Phase one focused on the communal heart of the College including the dining hall, common rooms and library. Phase two addressed the accommodation blocks. This strategy ensured that each application fell below the threshold for a major application, helping to speed up the consent process. To reassure the heritage bodies, the application for phase two was submitted before the first was determined. This demonstrated a clear commitment to a single and consistent solution across the entire campus preserving the uniformity that is so critical to Jacobsen’s design.

Navigating difficult but necessary compromises

A project this complex involves difficult compromises. All parties accepted that the works would result in the loss of original fabric. A significant knock-on effect of removing the RAAC roof was that large areas of original 1960s glazing also had to be removed. It was directly attached to the RAAC panels and was too fragile to be safely retained and put back. This was a bitter pill to swallow and the solution was to adopt a strictly heritage-led approach to the replacement. A detailed glazing study was undertaken to fully understand the significance of the original glass. The replacement, a laminated annealed float glass, is visually indistinguishable from the original but meets modern safety standards. This decision carefully balanced the preservation of the building’s aesthetic value with the safety of its occupants.

Miriam Owen, Associate Director at Edgars, reflects on this decision and highlights a key lesson for any heritage project. “When faced with a necessary compromise, the ability to make the right call stems from the trust developed with all stakeholders. Because we had built that trust through our transparent and heritage-led process, we could collectively agree on a solution that, while difficult, ultimately preserved the building’s essential character and safety.”

A conservation-led future

At St Catherine’s, the Edgars team was tasked to balance the urgent need for structural safety with the responsibility to protect an architectural masterpiece. The key was a transparent and phased strategy, where every decision was interrogated from a heritage perspective first. It proves that even in a crisis, a collaborative and conservation-led approach can secure the future of the legacy buildings.

The lessons learned from this project for St Catherine’s College offer a valuable blueprint for other complex heritage projects. A strategy built on clear communication, intelligent phasing and honest negotiation can deliver solutions that are both swift and sensitive. It shows that we can act decisively to make our heritage assets safe whilst protecting the very essence of their significance for future generations. Work continues to get the buildings returned to full use and the project’s lasting legacy is a process defined by care, clarity and a deep respect for heritage.