This document provides a methodology for the evaluation of the potential for sustainable refurbishment of an existing building, as a means of contributing to the circular economy, to support the decision-making process. Sustainable refurbishment aims to close the gap between current performance and current requirements fulfilling authorities sustainability regulations and contribute to meet sustainability goals which maximizes the environmental, social and economic performance. It also aims to allow the adaptability to fulfil future needs. It can be used for a building or part(s) of a building, as well as a portfolio of buildings. This document gives a methodology for assessing performance characteristics of existing buildings in terms of: 1) Technical aspects 2) Adaptability 3) Usability 4) Social aspects 5) Energy, water and operational impacts 6) Quality of indoor environment (including health aspects) 7) Economic feasibility 8) Climate change resilience 9) Embodied environmental impacts The document describes the work to be done in main applicable categories of a 6 steps process: " Step 0: Establish brief of the object of the assessment " Step 1: Evaluating the building " Step 2: Sustainable deconstruction " Step 3: Sustainable construction process " Step 4: Sustainable commissioning " Step 5: Sustainable in use NOTE In this document the users are people and organisations using the building, including the facility management. In some buildings visitors are also important users and need to be taken into account. This approach is generic for all types of buildings. At present this document does not cover civil engineering work and it does not give benchmarks for the evaluation. Assessment of the impacts of sustainable refurbishment of buildings is covered by calculation methods described in EN 15978, EN 16309 and EN 16627.