BCD 2018

12 C AT H E D R A L COMMU N C I AT I O N S C E L E B R AT I N G T W E N T Y F I V E Y E A R S O F T H E B U I L D I N G CO N S E R VAT I O N D I R E C TO R Y 1 9 9 3 – 2 0 1 8 The reaction of the chair of the board of governors suggests that the significance of the whole is inextricably linked to its integrity as a composition. Emotional, certainly, but carrying a certain academic weight, such a response can easily become the driving force for an attempt to recreate a lost place of symbolic value. So which is more important, built heritage or cultural identity? The success of any reconstruction relies on understanding those intangible values that contribute to public affection, ensuring that they are upheld through the reconstruction. They may endure the replacement of the original physical structure, so long as its key social and cultural characteristics are understood and maintained. Restoration is only a valid response where there is sufficient evidence to reproduce an earlier state of the fabric. Thus it is important to gather as much evidence as possible: written and drawn archives, measurements and photographs, conjecture and interpretation. A fire can diminish or destroy, but it can also reveal layers of history that have long been forgotten and original designs or historic construction methods can begin to be communicated. In some respects, these discoveries have the potential to yield information about the past and can offer a new understanding or interpretation of a building, prompting new research and investigation. A greater emphasis is required on the precious fabric that remains in order that it might be saved. Preservation and change are thus integral to the conservation of fire-damaged buildings and neither is mutually exclusive. To balance the effect of the loss of the original fabric, the opportunity for a new understanding should also be realised in the reconstruction. This approach invariably recognises the potential of change to reveal and reinforce value. CONSERVATION METHODOLOGY At the very beginning of the Glasgow School of Art project it was established that a complete reappraisal of how we manage, analyse and, most importantly, make use of the large quantities of archival and archaeological information to enhance the quality of the reconstruction, was required. The solution was to develop a cyclical working process, employing laser scanning and 3D modelling with building information modelling (BIM) as the binding element of three main areas of focus: research, production information and construction. Rather than viewing these as distinct categories, they were identified as three working areas (see below), all of which must inform one another, and all of which have a unique output. Library The research area of focus was called the library, because it is a growing resource that can be referred to throughout the project. It contains the exploration and collation of relevant archival sources to enhance the quality and accuracy of the reconstruction. As an output, we create a comprehensive set of documentation which informs our conservation philosophy and records the condition of the building, the works required and recommendations for the future. Studio The production of technical and design information is called the studio. It is where BIM comes into play as a design tool and repository for all project knowledge. This work relies on the outputs of the other areas to inform what we design, draw and build. The result is a comprehensive BIM model which can be used for facilities management and as a future learning tool. Workshop This is the live site environment, where intelligent and informed proposals are thoroughly tested, developed and finally realised. Lessons learned from physical prototyping feed back into our working studio to refine proposals. This process is cyclical because no element is ‘complete’ until the end of the project. Rather, the main focus shifts throughout the project timeline. Everything that is learned from archive research and from real-world sampling and testing feeds into the building information model. The work in each area should never take place in isolation, rather it should constantly enrich the output of the others. The end-goal is to deliver not just a comprehensive and seminal historic reconstruction, but also highly detailed building information as a future heritage asset. One of the most important parts of the Glasgow School of Art project is the reconstruction of the library. It is the area of the project that best illustrates our approach to information management and BIM integration. Just as each timber element exists as a separate component, it is modelled as a separate component in the digital environment. It is then tagged with a unique reference number and multiple fields of information relating to it. For example, by clicking on a specific timber in the model, it is possible to access not only information about its physical properties, but also what evidence existed to justify the reconstruction of that element. Any photographs, archaeological detail or survey data relating to the element are embedded in the model. The result is an interactive conservation tool which justifies in fine detail the evidence-base for reconstruction and supplies in-depth practical information to the contractor. In order to interpret and assess the significance of the information, the methodology described below was established. From the outset of the project, a view of what is currently known must be assembled. In broad terms, this can be described as: • original intention • pre-fire knowledge: what has changed since the original construction? • post-fire knowledge: what did we learn from the fire, fire-spread and underlying construction? • From this knowledge we can begin to assess and understand the consequences of the fire, which can be categorised as: • repairable: elements of existing fabric that can be retained • damaged: fabric which has been partially lost but is sufficiently intact to be analysed and measured to inform a faithful reconstruction in new material (physical evidence) • destroyed: fabric which has been completely lost. South elevation, laser scan of library (Image: Glasgow School of Art) Detail of library carving (Image: Page\Park Architects)