AbstractFor sustainability purposes, steel reuse at the material, structural element, and structure levels has been proposed and encouraged in recent years. Designing for deconstruction or disassembly is identified as one key strategy. A recent RFCS (Research Fund for Coal and Steel) project – REDUCE – has investigated the methodology and opportunities to design and facilitate the reuse of composite structures in steel frames. Furthermore, a demonstration building – the Pavilion “Petite Maison” – has been constructed using the solutions developed within REDUCE. The “Petite Maison” is located in Esch‐sur‐Alzette, Luxembourg, and it contributes to Esch2022, European Capital of Culture, by promoting circularity, reuse, and sustainability. It is open to public visits and is planned to be deconstructed with elements being tracked for reuse. This paper presents the design concept of the structural system of the “Petite Maison”, proposals of standard and modular elements and kits, and the analyzing methods for adaptable steel connections and demountable shear connections that are applied in the system.