The Mixed-Use Ground Floor
This pattern is shaped by
Problem
When residential buildings have residential ground floors, the street frontage is dead — closed blinds, private spaces, nothing to attract or engage pedestrians. When commercial buildings have commercial ground floors in a residential area, the neighborhood becomes a business district. The mixed-use ground floor resolves this: living above, working and gathering below.
Evidence and Discussion
The pattern is as old as cities: the shophouse, the walk-up with stores below, the live-work building. The specific design moves that make it work: ground floor ceiling height of at least 3.5 meters (flexible enough for either commercial or residential use), large display windows at street level, separate entrances for commercial and residential, and plumbing rough-ins for both uses.
Therefore
in any building at the center of a walkable density gradient, design the ground floor for mixed use — at least 3.5 meters ceiling height, display-scale windows, separate entrance from upper floors, and rough-ins for both commercial (grease trap, higher electrical capacity) and residential use. The ground floor should activate the street: a café, a shop, a clinic, a studio, a workshop. What it is matters less than that it is open, visible, and contributing to street life.