This chapter examines the evolution of the construction sector in Spain through the case of Construcciones Calderón, a family business founded in 1949 that managed to adapt to the profound economic and social transformations of the country. Over seven decades, the company went from carrying out small local projects to participating in large infrastructure and urbanisation projects. The text analyses how Calderón navigated the sector’s cycles of boom and crisis, especially during Franco’s developmentalism, the real estate boom of the 1990s and 2000s, and the subsequent recession after 2008. It highlights the company’s ability to adapt through diversification, professionalisation, and intergenerational management. In addition, the chapter reflects on the contemporary challenges facing the sector—sustainability, digitalisation, and new forms of financing—based on the specific experience of this company. Overall, it offers a microhistorically view of a key sector for the Spanish economy.