Historic Churches 2020

8 BCD SPECIAL REPORT ON HISTORIC CHURCHES 27 TH ANNUAL EDITION the constructed building and how early repair issues had been addressed. The cathedral was also placed within its international and national architectural context, from the medieval gothic tradition to the modern ideals of the postwar church. Oscar Niemeyer’s Brasilia Cathedral (1958–1960) in Brazil and Auguste Perret’s Notre Dame du Raincy church in Paris, were both early influences on British architects. The assessment of significance for the cathedral was grounded in national and international best practice, but was further developed in reference to the way Gibberd himself approached the building when he wrote his book Metropolitan Cathedral of Christ the King, Liverpool in 1968. Within this, Gibberd set out his design intent for the scheme and broke the structure down into three core components; structure, architecture and art. As a piece of total art, every part of this building contributed to each of the three components to some degree. As an example, the lantern holds structural significance for its innovative concrete frame and rare structural glazing, illustrating the postwar development of these materials. Architecturally, the lantern forms a silhouette on the Liverpool skyline, complements the Anglican cathedral and acts as a beacon for the spiritual life of the cathedral, as any church tower might. Artistically, the lantern holds one of largest stained glass windows in the world, which shines light into the sanctuary. It represents the Holy Trinity in its abstract tricolour of light. Assessing the significance of the lantern in this way reflects a site specific approach which focuses on the primary attributes of the place as perceived by the architect and by those who regularly engage with the building – the congregation and the wider community in particular. However, the significance of the cathedral and its components also had to be assessed from the perspective of national and international value systems, such as ‘special architectural or historic interest’ (UK legislation) and ‘outstanding universal values’ (UNESCO’s world heritage guidance). The relative significance of each component may then be broken down into different levels such as exceptional, high, medium, low, neutral and detrimental. Both the tangible and intangible values of the cathedral were drawn out in the assessment of significance, and an assessment of the relative levels of significance was applied to each component. This assessment was referred to throughout the conservation project to ensure that harm to significance was avoided, and where possible, significance was enhanced. Step 2: Vulnerabilities and opportunities It is important for any conservation management plan to provide an explanation of what is happening to the significance of the building, how it might be vulnerable, where there are conflicts with other values and what the potential threats are to its longterm survival. The climate crisis, for instance, is resulting in greater volumes of rainfall which the lantern at Liverpool is already having to cope with. Harm could be caused by a major change such as a roof replacement, but it could also be affected by incremental and cumulative changes. For example, the ‘waterproof’ silicone coating painted on the outside of the lantern affected its reflective qualities externally and reduced light internally. Other issues might relate to management and use, repair and maintenance, accessibility, visitors and how the building is explained to them, art or collections. Inherent defects identified in 20th century buildings have long been used to justify well-intentioned but inappropriate or excessive change. Without understanding the need or underlying cause, this can have a highly detrimental impact on significant features. Historically, it had been assumed that the epoxy resin holding the dalle de verre glazing in place at Liverpool had failed entirely. When investigations were carried out, it was found that gaps between the glass and the resin matrix had been there since construction. Some deterioration had occurred as a result of adverse environmental conditions but overall, the lantern was structurally stable. The research found that water penetrated through these fissures into the lantern, which then ran down the internal surfaces and pooled on the ring beam at its base before overflowing onto the high altar. Monitoring was carried out to understand how much was water penetration, and how much was from A crack in an area of the concrete frame which had been repaired with resin in the past and dusted with powdered slate to reduce its visibility Interior view of the glass slabs showing resin from earlier repairs smeared across the face (All photos: Purcell)