Water infiltration through the floor slab of the main level of Sant Ildefons Market has led to corrosion of the reinforcement within the basement slab, together with concrete section loss. In response, Cornellà de Llobregat City Council commissioned a technical assessment to identify the causes of the deterioration, evaluate the condition of the affected structural elements, and define the interventions required to ensure their repair, durability, and long-term structural performance.