Steplight

Steplight is a winning response to the National Single Stair Design Competition’s challenge to innovate multifamily building designs using single-stair configurations that fit on typical parcels across the U.S.

The current zoning requirement of a two-staircase exit route in multifamily housing—a requirement that once served as a critical safety measure but has become outmoded by other safety advances—has a profound effect on what does and does not get built in many North American communities. Single stair buildings represent an opportunity to bring denser development to smaller-scale lots. 

The DBA entry focused on a typical San Francisco lot; the other cities in the competition were Austin and Portland, Oregon.

San Francisco is in the midst of a rezoning effort focused on areas of the city that have produced relatively little new housing in recent decades. Sited in “high-resource” neighborhoods, these underutilized corridors are well-served by existing transit and well-situated for families, but short on new housing. While they may be dense by American standards—with little vacant land—these areas are significantly less dense than typical San Francisco neighborhoods, characterized by one- to four-story buildings built to lot lines at both the front and sides. 

Steplight riffs on the city’s classic property-line lightwells with tiered massing, cascading open space, and mega-lightwells that support diversity, community, outdoor connection, and bright spaciousness.

The plan adds usable open space in line with the existing city scale and pattern. Paired with balconies and a social roof deck for expanded outdoor living, the placement of the shared rear yard contributes to the aggregation of open space created by typical surrounding lots, preserving neighborhood access to light and air.

With variation at each floor plate, this expression offers a unique mix of units—from studio to four-bedroom—filled with light and air and connected to nature and urban life. The plan activates the street edge and retains the customary backyard placement, contributing to the collective open space of the block and respecting the neighborhood fabric.

Through its refined response to single-stair reform, Steplight realizes the potential of the Family Zoning Plan with diverse, contextual housing that incrementally yet substantially inserts density and housing choice into these areas.

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Learn more about the 2025 National Single Stair Competition. 

Sponsors of the competition include Arnold Ventures, Livable Communities Initiative, Abundant Housing LA, Green Development Company, California YIMBY, East Bay for Everyone, Westside Urban Forum, California Community Builders, Urbanist Ventures, Joint Center for Housing Studies at Harvard University, Center for Building in North America, Build Casa, YIMBY Action, YIMBY Law, Housing Action Coalition, Housing Policy Innovations, Parking Reform Network, Strong Towns, and Codified Life Safety.