Upcycling is identified as a process of the transformation of waste materials to which it is possible to give a value of artistic or environmental quality. To date, the greatest use of upcycling can be found in the design, art and fashion sectors. As in other sectors, one of the biggest challenges in the construction industry in the future is the search for new ways to reuse discarded materials. In this sense, upcycling is a new technique for the recovery of removed waste but with a much lower use of energy and resources than the regeneration of recycled material. With respect to these issues, the aim of this paper is to present the results of a design experimentation aimed at defining methodologies and tools for the reuse of building components from the decommissioning or renovation processes of existing buildings, with an approach that integrates both the disassembling and the re-assembling of construction elements, in line with the sustainable development and climate neutrality goals that the European Union aims to achieve by 2050. The methodology used made use of a field experiment by means of the creation of a prototype that made it possible to evaluate the results of the study which, if on the one hand made it possible to define an appropriate procedure for upcycling, on the other hand highlighted how these procedures save energy and reduce the emission of CO₂ in the environment. In this specific case, the experimentation gave the following results: energy savings 2038.92 kWh; CO₂ reduction 641.80 kg compared to a similar intervention from scratch. Therefore, the definition of a replicable and scalable operational process for the upcycling activity applied to architecture allows, by means of the reuse of those building materials and construction elements that still have a useful life, and which can, therefore, be used in the field of architecture, for a profitable contribution to the development of sustainable procedures in the field of architecture and the circular economy.

The construction sector has a high environmental impact, especially due to C&D waste. At the same time, the increase in the temperature of the Earth’s surface due to pollution requires interventions on the built environment, aimed at improving the performance of the envelope in hot climates. In the literature, there are studies on components to increase thermal efficiency, but they are limited by long or expensive production processes or high environmental impact. This research considers Italy as a reference area. The aim of this research is to design, prototype, and verify a sustainable component to be included in the stratigraphy of light mass vertical closures to increase their heat capacity that allows for the reuse of C&D waste and the optimization of site operations both in the selective demolition phase and in the redevelopment phase of the building. The method follows the following phases: analysis of the type of waste from C&D, analysis of international best practices, analysis of the possibilities of intervention on vertical closures according to the pre-existing structure and choice of cases of greatest scientific interest, design of the sustainable big bag by reusing inert materials from selective demolition and recycled polypropylene fabrics, prototyping and verification by laboratory tests, and software analysis to verify the thermal advantage. The use of the sustainable big bag allows for construction advantages, facilitating site operations both in the construction and waste disposal phases, energy advantages by improving the heat capacity of the envelope, and increases in the sustainability of the intervention through the reuse of waste materials.