Capturing, analysing and interpreting the complexities of built heritage in historic cities : cultural approaches and BIM methodologies for appropriate conservation

Built heritage is a key contributor to the quality of the environment in historic cities and its conservation requires a cultural approach and specific tools and methodologies to analyse and interpret its complexities. In an increasingly globalized world, it is important to conserve the richness of built heritage while allowing adaptations to address energy and climate issues. One of the main challenges is the perceived need for extensive retrofitting of buildings, without specific evidence from their thorough assessment, currently absent or poorly done. Building Information Modelling (BIM) is often presented as a solution to design and manage existing buildings. By reviewing literature and a case study, this paper discusses the current approaches, methods and tools concerning the use of BIM for architectural conservation and retrofitting purposes, looking at the issues of accuracy and integration, including intangible heritage and energy aspects. It discusses the current methodologies and the technical shortcomings of creating an accurate and reliable digital representation of existing buildings, vital to assess their condition and design the intervention, beyond the simple documentation of the building. The findings indicate that, although BIM software is quite developed, the current overall methodologies extensively rely in manual and labour-intensive processes, error-prone and contradicting the BIM principle of efficiency. There is also clear lack of integration of BIM and Building Performance Simulation (BPS), and in consequence a lack of real comprehensive project collaboration and understanding of a building's performance. Overall, there is too much focus on the individual tools rather than a cultural approach and an overall scientific assessment of BIM efficiency and accuracy and its suitability for existing buildings.