Designing A San Francisco With The 100,000 New Housing Units The City Needs

What if you could build housing in the gaps between a city’s buildings?


To bring down San Francisco’s out-of-control rents, the city’s chief economist estimated that it needs to build an extra 100,000 housing units in the next few decades. The problem is where to build: Residents tend to argue that there’s no space and aren’t interested in new developments that replace old San Francisco buildings.


In a new exhibition at SPUR, the San Francisco Bay Area Planning and Urban Research Association, architecture students show some innovative ideas about where those 100,000 units could fit.

Under the city’s new Affordable Housing Bonus Program, developers can now add an extra two stories to buildings in some areas if they meet certain requirements for including affordable apartments.

One part of the exhibition looks at how much housing could be squeezed into that extra space–and into gaps left by short buildings that don’t reach the height allowed by current zoning.

After conversations with a city planner, two professors at California College of the Arts led a studio asking students to look at that unused space. “We started talking about underused capacity in the city, and this myth that San Francisco has no place to build and that’s why we have a housing crisis,” says Christopher Roach, an architect and adjunct professor at CCA, who co-curated the exhibition with CCA professor Antje Steinmuller.

“If you know, for instance, that large sections of Mission Street are zoned for 65 or 85 feet, and you walk by a little one-story shoe shop or auto body repair shop, you’re just like, ‘Oh my gosh, we could build housing on top of this thing,'” he says.

The students mapped out those gaps, and the space available if all buildings in a neighborhood could also add two stories. Then–taking inspiration from other cities, like the elevated walkways in Hong Kong and rooftop additions in Vienna–they modeled ways that the space could be used.


On a stretch of Lombard Street lined with motels, for example, they envisioned building housing towers in the motel parking lots. Long elevated walkways would cross between towers, with more apartments built on top of the walkways. The design would also cover most of the wide street with a new traffic tunnel; on top, a pedestrian walkway would pass new museums, schools, and other public buildings.

On part of Third Street, apartments built into bridges would stretch over a wholesale produce market and connect to more towers.

While much of the current building in San Francisco have been high-rises located closer to the downtown area, the designers wanted to look at different neighborhoods where it’s currently politically difficult to build, pushing people to reimagine how those neighborhoods “should” look.

A second part of the exhibition, from students at Yale, considered how the 100,000 units could be added by rethinking how people live, inspired by the coliving arrangements that many San Franciscans already use out of necessity.

“They start with this premise of trying to find ways of developing collective forms of living and working that don’t put people into indebtedness,” says Roach.

Looking at vacant or underused city-owned spaces throughout the city–such as the middle of a wide road–they identified places to build new housing cooperatives, and then focused on how the housing would be arranged inside.


If most apartments in the city have one or two bedrooms, these apartments were designed from scratch to include space for dozens of people to live together, making private space more public.

All of the designs are meant to help people see the city differently. “We feel like our job . . . because we are somewhat insulated from the politics, is to push the boundaries, and maybe provoke people a little bit to think beyond the kind of constraining image of the city that they have right now,” says Roach. “In a way it’s a thought exercise to get us out of the kind of paralysis that we’re in in terms of addressing density in San Francisco.”

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About the author

Adele Peters is a staff writer at Fast Company who focuses on solutions to some of the world's largest problems, from climate change to homelessness. Previously, she worked with GOOD, BioLite, and the Sustainable Products and Solutions program at UC Berkeley, and contributed to the second edition of the bestselling book "Worldchanging: A User's Guide for the 21st Century."