ENAC week workshops bring together bachelor students in architecture, civil engineering and environmental engineering. Constructive Second Hand considers circular economy as an opportunity to better design while reclaiming wasted elements. For a whole week, students are invited to the Smart Living Lab in Fribourg, CH. Each group has one goal: to build a piece of furniture while reusing discarded elements from local industries. The week gives full autonomy to the student groups and comprises three steps: material identification & collection, design & construction, and demonstration. A jury eventually discusses how embedded functional and technical qualities are reclaimed, as well as the potential for large-scale repeatability.