Neuchâtel Penthouse is a 180 m² renovation of a two story apartment in Polanco, Mexico City. The project is organized around a sculptural central staircase that defines the spatial identity of the home through material continuity, light, and proportion. Warm walnut surfaces, stone volumes, and controlled natural light create a sequence of calm and connected spaces, while a fireplace integrated beneath the stair transforms residual space into a central architectural element.