This paper examines the evolution of demountable constructions in mid-20th century architecture through industrial patents, retracing early experimentation with principles now associated with Design for Disassembly and Adaptability (DfD/A). Conducted within the PRIN PNRR 2022 research project “Upcycling and Architecture in Italy. Forging and Promoting a Renewed Building Culture”, this paper investigates how past innovations in prefabrication, modularity, and dry assembly anticipated contemporary design strategies aimed at saving non-renewable resources, later formalized in standards such as ISO 20887:2020. Using a rigorous archival research approach, the analysis focuses on patents filed in Italy between the 1940s and 1960s, a period of intense experimentation in construction industrialization, largely driven by post-war reconstruction. Through a systematic comparison of selected patents with DfD/A principles – reversibility, modularity, adaptability, and structural independence –this study highlights the technical and conceptual continuities between practices of the recent past and contemporary circular construction approaches. Particular attention is given to the patents filed by architect Olga Caminati (1943–1945), selected as a case study and examined through constructive redrawing and digital modelling techniques. Based on extensive archival research within the Italian Office for Industrial Patents and Trademarks (Archivio Centrale dello Stato) in Rome, this work contributes to bridging a critical gap in the historiography of industrialized construction, exploring historical precedents that help contextualize approaches and methodologies informing contemporary discussions on sustainability and circular design.