This paper reflects on the pedagogy used for a series of student workshops on building with reused materials at the Ecole Polytechnique Fédérale de Lausanne (EPFL) and presents the results of its 7 th edition, which focused on floor systems. During these workshops, a learning-by-doing approach encourages collaboration in complex design tasks among architecture, civil engineering, and environmental sciences students. Addressing conventional floor systems' high embodied carbon footprint, the 7 th edition invited interdisciplinary student teams to develop and build an office-building flooring system made with non-conventional materials, i.e., reused components, bio-based and geo-based materials. The four student teams completed a preexisting load-bearing floor system made of reused concrete and steel elements with all the missing non-load-bearing flooring and ceiling layers to meet technical and comfort requirements. As a result of a 5-day hands-on workshop, original flooring and ceiling systems were designed and built by each of the four teams. The paper describes each system and discusses the pedagogical outputs of the workshop.