The San Juan House is a private, single-family home located in the southern region of Mexico City. Two stories exploit the sloped terrain to provide 185 m2 of living space on two levels. The roof slab covering the central stairway runs parallel to the slope of the terrain and integrates the structure visually while regulating interior circulation. The home and windows are oriented to maximize natural lighting throughout the day. The use black pigmented concrete block on the façade evokes the volcanic rock bedrock that is the identifiable geologic feature of region.