Abstract
The abandonment of the built heritage, as a result of functional or technological obsolescence or as a consequence of cultural, social, and economic trends, is steadily increasing. This great number of buildings, worldwide spread, offers a huge opportunity to reduce the environmental impacts related to the construction industry. Nonetheless, the recovery and reuse interventions that require the implementation of residual technological performance, to accommodate new uses, are not always environmentally neutral. Therefore, a new design approach needs to be developed so as to improve the buildings’ technological performance and enhance resources and energy already incorporated in buildings. The circular economy principles in the building sector, performance-based building design together with downcycling and upcycling theories are applied to develop a methodology aiming to reduce the environmental impacts within the rehabilitation and refurbishment design process. Starting from the building analysis phase (historical, material, construction) residual performance is evaluated; then the design phase demonstrates that, according to downcycling and upcycling design strategies applied on building components and materials, it is possible improving the building to the required new uses while minimizing transformations and effectively reducing related environmental impacts. The reduction of environmental impacts depends on a careful assessment of the residual technological and structural performance that the building still provides, by involving limited performance implementations to balance rehabilitation needs and environmental protection goals.