Sustainable Revival: a Case Study in retrofitting obsolete buildings

This paper explores the environmental and structural value of retrofitting reinforced concrete buildings through the integration of Cold-Formed Steel (CFS) structures. Focusing on the San Nicolao case in Milan, the study highlights how non-code-compliant buildings from the mid-20th century (typically lacking seismic design and energy efficiency) can be preserved and upgraded rather than demolished. CFS systems, used within Light Steel Frame (LSF) technology, off er a light-weight, low-impact solution for structural reinforcement. These systems are designed with parametric tools that allow tailor-made components to be fabricated with high precision, enabling fast and non-invasive construction. Compared to conventional materials, CFS exhibits favorable values of Embodied Carbon (EC) and Embodied Energy (EE), especially when produced via Electric Arc Furnace routes with high recycled content. The result is a scalable, cost-effective approach to extending the lifespan of the existing building stock while reducing environmental impact. This strategy supports EU climate neutrality goals and offers a replicable model for sustainable transformation of obsolete urban structures.