###### Abstract  
The European building industry is facing a strong increase in renovation processes, which are still non-cost-effective, involve unproperly coordinated stakeholders, are disturbing for the occupants, and cause important inefficiencies in the overall renovation process. In this context, digitalization and Building Information Modelling (BIM), as an enabler, is the key solution that may drive renovation interventions to ensure a more successful and leaner process, aiding the whole value chain of actors to achieve its full potential. This research describes the OpenBIM methodology applied in order to transform the implicit knowledge from the stakeholders involved in the building renovation process, not structured enough for automation, into an OpenBIM digital process based on the BIM standards. The outcomes of this research are the OpenBIM ready workflows that represent the renovation process and information requirements according to the involvement of different stakeholders rooted in the analysis of barriers, requirements, and needs. Those workflows are the basis for the future development of specific products and tools for boosting digitalization and interoperability in the renovation process. building renovation; BIM; interoperability; OpenBIM; BPMN; workflows; digital construction; retrofitting; IDS +
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well as for renovation works [11]. Based on the application of collaboration principles, the adoption of BIM in the construction sector can significantly improve the efficiency of the overall process [12; 13; 14], with a direct impact on the reduction of costs, time, and waste. The strategy using BIM is mainly based on obtaining a common framework to work together by means of conceiving digital-based models that are to be shared among partners. Its main goal is that the involved stakeholders develop, in collaboration, a digital representation of the building, a design that is continuously updated, reaching its highest level of development once a digital twin is generated [15; 16]. This design provides reliable information about the different elements and components as well as the actuations planned. The exchanged data include a combination of geometric and semantic information, and the centralized models allow one to easily extract and exchange this information. The latest version of the model is accessible to all the participants and communication channels are established, thus cooperation is promoted, and uncertainties are reduced [17]. In recent years, BIM-based software has significantly increased its presence in applications related to architecture, engineering, and construction (AEC), covering all the phases and types of applications [5; 9; 17; 18; 19; 20; 21]. Its application worldwide in different countries with various working cultures and economies has also been studied in the past [13; 14; 22; 23; 24; 25]. One of the main characteristics of this industry is the concurrence of multiple and different actors, with various skills, knowledge, tools, applications, and software. All that information needs to be generated, adapted, exchanged, and interpreted between them. To make the process and the overall result of the actuation more efficient, a synchronization of this information is needed based on interoperability principles (i.e., how to connect systems and applications on a technical level) [26]. In parallel, and as part of this information exchange, communication needs to be facilitated between the participants. The current digital revolution with the proliferation of big data and AI should facilitate this change of paradigm [27]. The BIM methodology relies on interoperability as the way to reduce the barriers that hinder the exchange of information, as a result of the use of open standards. Among the possibilities for solving interoperability impediments that represent a barrier to information flow, OpenBIM standards such as IFC (ISO 16739) [28] and related standards are being promoted by buildingSMART.