At the foot of Red Mountain in Nanjing, Mix Architecture has completed Red Box, a compact commercial building defined entirely by red concrete. The project sits within the former grounds of the Nanjing Combat Machinery Factory, an industrial complex established in the 1950s that shaped the area’s identity for decades. Mix Architecture approached the building as a response to the site’s layered meanings of red, from the brick factory structures to the iron-rich soil of the mountain itself. By incorporating iron oxide into the concrete mixture, the architects created a material that reflects both geological and industrial histories, allowing the building to operate as a physical continuation of its surroundings.
ARCHITECTURE
The building presents a restrained rectangular volume toward the north, facing Red Mountain Park with a solid wall that reinforces its presence. This surface appears to float above the courtyard boundary, introducing a sense of weight and suspension at once. On the south side, stepped terraces recede upward, opening the structure toward the mountain and allowing vegetation and daylight to enter the architectural composition. These terraces establish a gradual transition between building and landscape, ensuring that the mountain remains visible from multiple vantage points within the project.
Entry unfolds through a triangular opening carved into the courtyard wall, guiding visitors along a controlled path before revealing a tall vertical space anchored by a six-flight staircase. This sequence emphasizes movement and spatial compression before expanding into open courtyards. The west courtyard functions as the primary public area, where a preserved tree stands beside a reflecting pool surrounded by corridors. Reflections of foliage and water introduce shifting visual conditions that change throughout the day. The east side provides quieter, more private spaces organized around smaller courtyards, maintaining visual continuity while limiting access.
On the upper level, a corridor connects two interior volumes and frames direct views toward Red Mountain. Semi-permeable acrylic walls embedded within the concrete structure allow filtered light to pass through the interiors. One surface uses a dotted configuration that creates a star-like pattern, while another introduces perforations that reference the rhythm of the site’s original brick architecture. These interventions extend the dialogue between past and present through material and light.
Extensive testing defined the final concrete mixture, ensuring consistent color and surface quality across the building. Wooden formwork introduced textures calibrated to echo nearby masonry, reinforcing the connection to the industrial context. Mix Architecture coordinated architecture, interiors, and landscape as a unified system, working with manufacturers to align every component with the design intent. Red Box stands as a precise architectural object shaped by memory, material, and environment.
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