The Building Conservation Directory 2024

47 CATHEDRAL COMMUNICATIONS THE BUILDING CONSERVATION DIRECTORY 2024 BUILDING CONTRACTORS 2 to allow the restoration teams to carry out their work safely and comfortably with protection from the elements. The public scaffold opened in 2015, generating press and media attention and further increasing the fundraising potential of the venture. When end-of-life roof slates were replaced, visitors had the opportunity to name and sign messages into the replacement tiles for a small donation. The scaffolding structure above the orangery included a promenade loop 25 metres above ground. This enabled visitors to physically scale the scaffolding to see the conservation works in action and engage with contractors, who ran daily Q&A sessions and demonstrations. While this added complexity and meant a more expensive scaffold was needed, the extra dimension to the visitor experience helped to recoup a significant amount of the overall scaffolding spend through increased visitor numbers, donations and footfall across the park’s estate. Meeting the National Trust’s requirement for visitor access led to extensive consultations with scaffolders, contractors, the building inspector and the trust’s insurers, all at pre-tender stage, to resolve how these ambitions could be safely achieved both in terms of practicality and compliance. DIVERSIFYING AT HEIGHT Working at height is one of the most dangerous factors to consider on a conservation project. As with Dyrham, our work at Canterbury Cathedral often involves raising teams of skilled craftspeople high above the ground. The Cathedral is one of the oldest Christian structures in England and part of a UNESCO World Heritage Site. As Surveyor to the Fabric at Canterbury, it is my duty to protect and safeguard the fabric of the building, while making sure the building does not present a risk to the public and the cathedral community. As part of Purcell’s repair of the cathedral’s nave vaults and nave clerestory windows, we faced a dual challenge of creating a safe place to work at considerable height whilst protecting ongoing worship in the space below. Rather than attempting to hide the scaffold or provide a costly photo reproduction of the vaults, we designed something intended to be seen: a new, temporary ‘canvas’, capable of hosting artwork whilst also matching the imposing magnificence of the cathedral. Headlining these installations was Arabella Dorman’s evocative artwork Suspended, which highlighted the plight of refugees by suspending the items of clothing they discarded when boarding boats bound for mainland Europe. It was described by The New York Times as our ’most talked about contemporary artwork.’ SECURING STRUCTURES SAFELY A more unexpected event at Canterbury called for swift action to prevent immediate further damage to the building and to protect the public and cathedral team. When a lump of masonry fell from the Great South Window at the cathedral in 2009 it was a dramatic indication that something was seriously wrong. Urgent inspections revealed that the window was structurally failing. Following consultation with ecclesiastical and heritage bodies, it was agreed that the precious glass could not remain in the decaying stone frame. The whole window would have to be dismantled and rebuilt, salvaging as much of the original stone as possible and rebuilding where necessary using traditional materials and techniques. At 17 metres high by 7.5 metres wide, dismantling and reinstalling the towering window required careful planning to ensure the safety of the public, the conservation and cathedral teams and the building itself. Investigations soon revealed cracks in the stonework holding in place some of the most precious medieval stained glass in the world, elements of which date from the 12th century. The stakes of safety and caution could not be higher. Not only is the window extremely high and a potential risk to anyone working on it, but it is also spiritually, culturally and historically precious. The engineers assessed the state of the window and concluded that it was currently safe enough to build a frame on either side of the window, effectively sandwiching the historic masonry between scaffold towers so that no more bits of the window could fall. Once built, the scaffold allowed conservation specialists to access and survey the window safely. Working on the conservation principle of ‘as much as necessary, as little as possible’, we ascertained that the upper tracery was in relatively good condition and questioned whether we could devise a method to retain the tracery in situ whilst underpinning with new masonry below. We developed this concept with finite element analysis, structural temporary works designs and physical prototype formwork to test the concept in advance of our formal applications for consent. The immense scaffold required for re-roofing Dyrham Park was adapted to allow safe access for National Trust visitors, large and small, allowing the site to remain partially open during the work. (Photos: Clare Green Photography) The spacious area of scaffolding at Dyrham also helped the restoration teams work safely and comfortably. (Photo: Barry Batchelor Photography)