EU regulations encourage member countries to a rate of renovation, of the existing building stock, of no less than 3 percent per year. With respect to an Italian landscape strongly characterized by a building stock with reinforced concrete structure, now at the end of its life, this action is realized through a replacement approach. One of the most effective strategies for achieving the construction sector’s sustainability goals is to move toward a circular-type process, of the sector. This is achieved by maximizing the reuse of building components to be decommissioned, at the end of their life, through the method of “upcycling”, a design of the ‘new’ aimed at reusing materials from a demolition/reconstruction (C&D) process that avoids their disposal in landfills. This strategy makes it possible to reduce the environmental impact associated with both the disposal of waste materials resulting from the demolition of the building and the extraction of new raw materials, for new design. The study developed an integrated model, called the “Classifying Method”, which analyses three end-of-life building complex disposal scenarios: landfill, recycling and reuse. The objective of the method is to determine a “ranking” aimed at identifying the most virtuous scenario, both in terms of environmental impact and economic viability. On the subject of Ecological Transition, this study aims to propose a methodology as a concrete response to the following areas: