Circular design: reused materials and the future reuse of building elements in architecture. Process, challenges and case studies

The design process in which existing materials are reused or which aims to enable future reuse of building elements differs significantly from a standard design trajectory. Working with construction waste requires material tests, assessments, and consultations as well as defining available waste sources. Designing for future reuse demands extended research on the layers of buildings, properties of materials, dismountable joints, maintenance techniques, and reuse scenarios. This results in a longer introductory phase and often in a higher cost of the project. Circular design also faces other challenges, which concern environmental (e.g., recycling potential), social (e.g., social perception of reused materials), infrastructural (e.g., lack of processing plants) and legal issues (e.g., non-flexible construction law). These aspects often influence already technically complicated design process. However, there are projects in which reused materials were successfully implemented. Buildings designed for future reuse of their elements are also being built. In this paper selected case studies from Germany, the Netherlands, Poland and Denmark present how different types of construction waste (incl. waste from concrete, brick, wooden, metal, plastic and glass elements) can be reused in architecture. Moreover, this article analyses the circular design process, related challenges and investigates the emerging role of the architect.