This project for a rooftop duplex apartment from the 1950s intervenes delicately and discreetly in the existing building by lightweight steel structure with precast slabs, forming a large and unique space on the upper floor that houses an office area and an outdoor terrace. In the lower floor a general reform and modernization was made, adjusting the opening of the slab for the staircase inside the space of the kitchen and living room, integrating the environment as a whole.