How might we put affordable housing on disused & small sites in San Francisco?

Tim McCormick
Nov 4, 2015 · 4 min read

by Tim McCormick, November 3, 2015

I. Tax Breaks, on the Urban Agriculture Model

This past year, California passed legislation AB551 creating tax breaks for urban farms. If urban land-owners agree to let disused lots be used for an urban farm for 5 years, the property tax on it can be reduced to that of agricultural land (effectively, negligible). Many people have questioned why a state with huge urban housing shortages would give tax breaks to incent gardens on vacant land, rather than housing. (see The Atlantic,, etc).

mapping of disused spaces, by dSpace project / Nicholas de Monchaux’s Local Code project

On the other hand, I think the program might provide a useful model for a similar interim-use legislation for housing. In writing & passing that legislation, sponsors had to have looked into a lot of issues about what would be legally & administratively possible. Good lead work!

I think one reason people don’t usually think of such an approach for housing is that hardly anyone conceives that (legitimate) urban housing can be moveable or temporary — even though there are plenty of precedents, including low-cost new housing being erected in London currently (Y:cube, and other projects from YMCA London branches). In my opinion, interim-use housing is potentially a huge opportunity, because large amounts of land goes disused for long stretches of time: because land-banked, planned for development, in dispute, in appeal, project lost financing, business cycle goes down, current owner not incented/focused on developing (eg govt agencies), etc.

It’s an interesting question why cities today mostly don’t imagine movable/temporary housing. They do fairly widely embrace other types of building/facility that are moveable: such as popup retail (e.g ProxySF, The Yard at AT&T Park, etc), modular classrooms, modular offices at building sites, etc. Movable/modular housing is pretty common in many industry contexts such as energy industry, or construction workers; and of course trailers/RVs/manufactured housing are widespread in US.

Anyway, I think it’s another case where tangible proof-of-concept projects are key to overcoming preconceptions. Also, particularly in California, the development of interim-zoning provisions, more formalized than existing Conditional Use process, which might be not, or less, subject to permanent-use procedures such as CEQA (state environmental law) appeal.

II. Small Site / Public Surplus Land

Issues of private disused sites tend to overlap with issues of small-site and public-surplus sites development. As the dSpace project map suggests, and as the current Proposition K (ballot measure) addresses for SF city-owned land, most cities have many disused land parcels, particularly smaller ones. Often, smaller lots are considered undevelopable by conventional housing/building developers, as (in their assessment) the fixed costs of dealing with any site couldn’t be recouped. Traditional “affordable housing” ie BMR developers rely on Fed/State subsidy funds that often can’t be applied to building smaller than 40 units. Importantly, there is also an exemption in CEQA for small infill sites, which removes a key procedural/appeals barrier.

The other week I spoke to PropK’s sponsor, SF Supervisor Jane Kim, at an affordable housing event, and asked her if a) its requirement for city agencies to inventory land might be extended to smaller parcels than its current 1/4-acre threshhold, and b) if we might do a contest to invite proposals for how to create housing on such parcels, since they’re currently mostly considered unusable. (even though most current SF housing is on lots smaller than 1/4 acre = 11,000 square feet!). She seemed quite interested in both. Subsequently I had a chat about it on Facebook with architects Mark Hogan and David Baker, who are both very involved in affordable + infill housing, and with Kearstin Dischinger of SF Planning.

PropK calls for ‘surplus’ public lands to be preferred for sale/lease to development of 100% affordable (defined as up to 120% AMI) on projects < 200 units. It also says “Establish policy that the first priority use of surplus City-owned property shall be for the purpose of providing housing, shelter, and other services for people who are homeless.”

This is all interesting because it may help create significant momentum, if not mandate, for many land parcels to be used for homeless and affordable housing. And in many cases, particularly smaller parcels, existing parties/models may not particularly have means or priority to do that, opening a door for new proposals/approaches. In response to the omnipresent question “where do you get the land?” raised whenever any housing idea proposed, we can note, actually there’s land available all over, even in the densest cities, which cities and owners may wish or be willing to use for housing, but don’t see how to by conventional means.

So let’s consider all the possibilities for using this land creatively: prefab demos, self-build projects, digital fabrication eg WikiHouse — let a hundred housing flowers bloom!

video for dSpace project, proposing reuse of SF disused spaces

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Tim McCormick

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editor, @YIMBYwiki; founder, @Houslets (open-source modular building research & design), San Francisco. @Possibilist_. tmccormick at gmail.

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