Waldo Galle is assistant professor on sustainability transitions at Vrije Universiteit Brussel (VUB) and associate researcher for the Flemish Institute for Technological Research (VITO).As a member of the research groups VUB Architectural Engineering, and Business Technology and Operations, I study the financial and socio-technical feasibility of a circular construction economy. I question which opportunities the transition towards that economy raises, which constraints it creates, and how the architectural practice changes together with it.Trained as an architectural engineer (Ghent University, 2011) and doctor in engineering (VUB, 2016) I gained expertise on the environmental savings, functional resilience, and financial feasibility of circular building during fundamental and strategic research, and developed policy recommendations and design support tools in applied and consultancy projects. Together with prof. Niels De Temmerman, I develop this expertise further in for example ‘Aterlier Circulair’, a learning network of over 60 designers.Familiar with methods for system analysis, interactive redesign and reflexive monitoring, I explore also more strategic opportunities and hurdles, such as the changing business model of architectural firms, or the absorptive capacity of small and large construction companies. As a member of the VITO Nexus, I apply these methods also in support of various international projects on the circular economy and related regional policies, for example in collaboration with EIT Climate-KIC.Relying on educational experience and training, I give lectures, guide students, and assist in training sessions for scholars and professionals on circular building and sustainability transitions. Together with prof. Cathy Macharis and Bieke Abelshausen I am also titular of the university-wide elective course ‘Sustainability: an Interdisciplinary Approach’, wherein community-engaged research and learning are put to action.Finally, I see the transition towards a sustainable built environment – respectful of our planet’s boundaries, for which I care much – as one of today’s wicked challenges. To tackle such challenges, I aspire to fresh research approaches and cross the boundaries of our lab, into the city. By confronting my results with those of peers in other fields and with the concerns of actors outside the safe academic realm, I truly want to support sustainable development. Therefore, I am always open to new insights and collaborations.