The Building Conservation Directory 2024

48 THE BUILDING CONSERVATION DIRECTORY 2024 CATHEDRAL COMMUNICATIONS The scaffold obscuring the nave ceiling of Canterbury Cathedral provided an opportunity for thought-provoking art installations, such as Arabella Dorman’s Suspended, which used discarded clothes to highlight the plight of refugees (Photo: Canterbury Cathedral) The Great South Window in the south transept of Canterbury Cathedral: much of the tracery had to be replaced to ensure its stability in the long term. (Photo: Purcell) Through this we learnt that the pursuit of minimal intervention, whilst technically possible, would pose a greater risk to the workforce and longer-term surety of the fabric. The required support scaffold meant that access to the window was restricted. On the one hand, it provided accessibility for the restoration team, whilst on the other hand it presented an obstacle. Cleaning, setting out, measuring, protecting, dismantling, repairs and reinstallation all had to be undertaken by the cathedral’s masons and glaziers by hand. Many of the stones weighed more than 250 kilograms and some as much as half a tonne. Weighing the dangers, it was eventually decided to fully dismantle and rebuild. During the works the entire support scaffold was enclosed to enable year-round work on the window. PLANNING FOR THE FUTURE Increasingly we marry traditional knowledge of materials, techniques and methods with innovative technology like building information management (BIM). BIM is an essential part of our heritage conservation work on many of our current projects including Manchester Town Hall and the Elizabeth Tower (Big Ben). It is the ‘I’ for information that is the most important value. In the past, we maintained and shared information directly by handing down know-how and niche skills from generation to generation. This is still the approach at Canterbury, where my own first-hand relationship with my predecessor as Fabric Surveyor gave me access to generations of knowledge about the characteristics of specific materials in particular condition, and their sometimes eccentric behaviour. In this way we were able to avoid misinterpreting the urgency of building and structural safety, while ensuring that we were not being complacent in our duties as professional advisors. But such a relationship is now the exception rather than the rule. With BIM, we are better able to record and preserve incredibly precise information about an historic building and this will serve the building well in the future. Properly employed, BIM should give us an ‘X-ray’ view of what lies beneath the surface of our completed works. In the future, this will be augmented with further innovations so that we can precisely map and record what we know about buildings, their individual materials and their distinct environments to help us care for and protect our heritage. Perhaps this should be extended to recording not only fabric condition and remedial actions taken at a point in time but also observations on the why and how we went about the work. This will give our successors the best possible chance of ‘standing in our shoes’ and making safe decisions about how and where they will intervene. JONATHAN DEEMING is a conservation architect, a partner of Purcell and Surveyor to the Fabric of Canterbury Cathedral.