Tag Archives: housing

Density – the limitations of zoning

San Francisco. CC image from C1ssou

A few days ago, Charles Marohn posted “It’s so much more than density” on his Strong Towns blog.  In it, Charles pushes back against the idea that density is good, arguing that the reality of great places is more complex. Marohn’s conclusion is spot on, but throughout his post he creates several strawmen arguments, some of which rubbed me the wrong way:

Equating planners with zoners: Charles styles this as “planners zoners.” In this world, all planners love zoning, and love the available tools that zoning offers. In my professional experience, this is rarely the case.

I’m not sure why planners zoners are generally so keen on density, but they are, to the point where it often comes across as an obsession. I have a theory. I think a lot of planners zoners yearn to be spatial planners. They go to school to build great places. They get out into the real world and are given this ridiculously blunt instrument — zoning — and are frustrated that they can’t wield it to create Paris. Few stop to ask what zoning regulations were used to create Paris (hint: there weren’t any). Density, especially when given as a bonus for attainment of certain performance objectives, is the closest thing a modern planner zoner gets to their professional roots. We all suffer the consequences.

Perhaps it’s the personalization of this that bugs me, because the analysis of the systems is spot-on. Zoning is a blunt instrument at best, but many of my fellow planners (not merely zoners) do indeed ask about Paris. They understand the limitations of zoning. They are also constrained within the system. They make use of the tools available.

The most realisitic path to change is from within, usually via a zoning re-write like currently underway in DC, or recently completed in Philadelphia. Wholesale repeal of zoning codes seems unrealistic. Even Houston, without Euclidian use zoning still bears many of zoning’s ills through other regulations, such as parking requirements. Change in the regulatory environment is likely to be incremental.

Still, these professionals must contend with pressures on them from various stakeholders. In Philly, the city council is trying to un-do many of the recent changes. In DC, many of the bad practices Marohn decries (using the mindset of zoning as incentive rather than allowance)  are urged by residents, not by planners.

Location matters: Regarding the desirability of density, there needs to be a distinction between using bonus density as an incentive and merely allowing greater density and letting the market supply it organically. Part of this confusion might stem from your frame of reference. During the rise of the housing bubble, Paul Krugman made note of America’s two distinct housing markets:

When it comes to housing, however, the United States is really two countries, Flatland and the Zoned Zone.

In Flatland, which occupies the middle of the country, it’s easy to build houses. When the demand for houses rises, Flatland metropolitan areas, which don’t really have traditional downtowns, just sprawl some more. As a result, housing prices are basically determined by the cost of construction. In Flatland, a housing bubble can’t even get started.

But in the Zoned Zone, which lies along the coasts, a combination of high population density and land-use restrictions – hence “zoned” – makes it hard to build new houses. So when people become willing to spend more on houses, say because of a fall in mortgage rates, some houses get built, but the prices of existing houses also go up.

For those of us in the Zoned Zone, simply allowing for more growth (and density) will produce different results than a similar regulatort adjustment in Flatland.  Anecdotes of these constraints in expensive cities abound: consider recent articles from Brooklyn and San Francisco, among others.

Marohn  notes that density does not cause productivity in places; density is a byproduct of productive (and valuable) places:

A strong town — a productive place — is generally of a higher density than an unproductive place. That financial productivity, however, is not caused by the density. There is a correlation — as productivity goes up, so does density — but one does not cause the other.

Leaving aside the question of correlation vs. causation, nothing in Marohn’s post takes the context of the place and pent-up market demand into account. Two planners talking about the desirability of density could use the same argument, but the location of the planner (Flatland or the Zoned Zone) dramatically changes the impact of that argument. In Flatland, where supply is not constrained, density not supported by the market must be shaped via some sort of regulation. However, urbanists advocating for density in the Zoned Zone are often just asking to remove the constraints that make density illegal.

With that in mind, attacking planners for pushing density without considering their context and market conditions (and the nature of the intervention) can confuse the issue. There’s no doubt that incentives can backfire – zoning is a blunt tool, after all. But that’s not always the motivation when arguing in favor of more density.

Perceptions of density often miss the mark: Marohn also cites the example of urban renewal as a failure of the fetishizing of density. I’m not sure that this narrative holds up to the history, however – at least as it applies to the density of urban renewal projects. As I’ve written before, perceptions of density are often well off from the reality.

This isn’t to endorse either the process or product of urban renewal, but the goals of those projects were often aimed at reducing density and overcrowding.

Beware unintendend consequences: As I noted at the top of this post, I don’t disagree with Marohn’s conclusion at all:

Ultimately, the notion that we can solve the problems that we face in our cities by simply increasing the density requirement in our zoning codes is not just naive, it is dead wrong. Density is an expected byproduct of a successful place, not the implement by which we create one. Building a Strong Towns is a complex undertaking, one that defies a professional silo or a simple solution.

More on Marohn’s follow-up, Density Redux, to follow…

The gated Washington region

The Gated City in action: Today’s Washington Post on the inadequacy of the region’s housing supply in meeting demand. In short, Ryan Avent called it. The region is producing jobs, people want to move here, yet it hasn’t been able to produce enough housing to meet that demand. From the Post article:

“If businesses find they can’t have their workers live near where they can work, they’re going to go somewhere else. And the workers themselves might also go somewhere else,” said Lisa A. Sturtevant, an assistant professor at George Mason’s school of public policy, who co-authored the study with Stephen S. Fuller, director of the university’s Center for Regional Analysis.

Their research showed that the Washington area, defined by 22 counties and cities, is expected to add 1.05 million jobs through 2030. More than a third of those jobs will be in professional and technical sectors, but significant growth also is expected in administrative, service and health-related jobs that often pay lower wages. If those numbers hold true, that boom will require as many as 731,457 additional units to house workers in the jurisdictions where they work, the study found.

That means the region would need to produce about 38,000 new housing units per year, “an annual pace of construction never before seen in the region and below what local jurisdictions have accounted for in their comprehensive plans,” the study concludes. Data show that over the past 19 years, the region has averaged 28,600 building permits a year; last year, about 15,000 building permits were issued in the region.

In addition, much of the new housing needs to be multi-family units (to make efficient use of available land) and affordable rentals (to put it within reach of younger workers and those with lower salaries), George Mason’s researchers argue.

For more on Fuller and his work, see Lydia DePillis’s April City Paper profile.

I must, however, take issue with the Post‘s framing of the issue.  From the second paragraph in the article:

With that growth comes a vexing problem: How do you house those new workers in ways that are both affordable and don’t worsen the soul-crushing commutes that already plague the region’s residents?

The problem here isn’t vexing at all.  Nor, frankly, is the solution.  The solution is rather obvious: we need to grow up instead of out.  We need to add density. We need infill development around existing infrastructure assets. Admittedly, implementing that solution is certainly more vexing than simply stating it aloud, but let’s not let the challenge of implementation obscure the diagnosis of the root problem.

Density, productivity, and housing prices

Ryan Avent recently spoke at the Kauffman Foundation‘s conference for economic bloggers. His short presentation touches on a number of economic issues as they relate to urban economies and their role in our national economy.

The presentation tackles Tyler Cowen’s Great Stagnation thesis.  Avent specifically looks at the benefits of density on productivity and innovation, and how the dispersal of the American population has had a disparate impact on American productivity.

The implications for cities are clear – the dense areas (owing to the benefits of agglomeration and economies of scale) are extremely productive, but they’ve not been the areas seeing growth in recent decades.  Instead, the less-dense places in the sun belt have grown.  Avent attributes this to the sun belt’s ability to expand supply and keep housing costs low (citing Ed Glaeser).  The implication is that the low cost of living is attracting people to areas that are less productive than the dense but hard-to-expand coastal cities.

Adaptation in housing, organically

A few housing-related tidbits that I’ve accumulated over the past week.

Richard Layman laments the lack of quality development, noting the difficulties involved with larger scale infill projects, especially when compared against smaller scale renovation projects of single rowhouses or small apartment buildings.  The smaller scale renovations take on a more organic character, while the scale of the larger projects necessitates more centralized planning and development.

As for your point about “organic” development, in my experience, which I admit is relatively limited, my sense is organic (re)development that includes significant amounts of new construction is more about adaptive reuse of extant places, complemented by (hopefully high quality) infill.

Along similar lines, Rob Holmes over at mammoth points to a great discussion of housing in Haiti (Incremental House, Wired), with a particular focus on adaptation and organic elements.  This isn’t the first time mammoth has mentioned the idea of incremental housing development, which Rob touched on in his very interesting list of the best architecture of the decade (including more infrastructural/engineered spaces like the Large Hadron Collider).  Quinta Monroy, an incremental housing project in northern Chile, has a fascinating approach to both building shelter and also growing and adapting with the residents:

Quinta Monroy is a center-city neighborhood of Iquique, a city of about a quarter million lying in northern Chile between the Pacific Ocean and the Atacama Desert.  Elemental’s Quinta Monroy housing project settles a hundred families on a five thousand square meter site where they had persisted as squatters for three decades.  The residences designed by Elemental offer former squatters the rare opportunity to live in subsidized housing without being displaced from the land they had called their home, provides an appreciating asset which can improve their family finances, and serves as a flexible infrastructure for the self-constructed expansion of the homes.

Quinta Monroy

Elemental’s first decision was to retain the inner city site, a decision which was both expensive and spatially limiting: there is only enough space on the site to provide thirty individual homes or sixty-six row homes, so a different typology was required.  High rise apartments would provide the needed density, but not provide the opportunity for residents to expand their own homes, as only the top and ground floors would have any way to connect to additions.  Elemental thus settled on a typology of connected two-story blocks, snaking around four common courtyards, designed as a skeletal infrastructure which the families could expand over time:

We in Elemental have identified a set of design conditions through which a housing unit can increase its value over time; this without having to increase the amount of money of the current subsidy.

In first place, we had to achieve enough density, (but without overcrowding), in order to be able to pay for the site, which because of its location was very expensive. To keep the site, meant to maintain the network of opportunities that the city offered and therefore to strengthen the family economy; on the other hand, good location is the key to increase a property value.

Second, the provision a physical space for the “extensive family” to develop, has proved to be a key issue in the economical take off of a poor family. In between the private and public space, we introduced the collective space, conformed by around 20 families. The collective space (a common property with restricted access) is an intermediate level of association that allows surviving fragile social conditions.

Third, due to the fact that 50% of each unit’s volume, will eventually be self-built, the building had to be porous enough to allow each unit to expand within its structure. The initial building must therefore provide a supporting, (rather than a constraining) framework in order to avoid any negative effects of self-construction on the urban environment over time, but also to facilitate the expansion process.

Obviously, applying this idea to a western city (as opposed to a slum) raises a whole different set of issues, but it’s a particularly interesting idea when contrasted against the highly planned and professionally designed structures Richard Layman notes.  It provides a jumping point to look at the continuum between several of the elements that the Incremental House mentions in their self-description:

Much of the housing around the world occupies a space in between the planned/unplanned, formal/informal and the professional/non-professional, offering people a small space space to negotiate the tremendous shifts taking place in the urban landscape.

DC’s stability provides less of an opportunity to shift between those poles, but the idea is nevertheless interesting.  Rob Holmes expands on what this means:

Elemental, in other words, have exploited the values and aims of ownership culture (which mammoth has suggested understands the house to be first a machine for making money and only second to be a machine for living) not to support a broken system of real estate speculation and easy wealth, but to present architecture as a tool that can be provided to families.  While the project is embedded with some of the assumptions of the architects (such as that faith in the potential of ownership culture, for better or worse), this tool is primarily presented as a framework, a scaffolding upon which families are able to make their own architecture.

Framework is a good way to put it – much of the work in planning seeks to establish frameworks (legal, physical, financial) around which cities and grow, evolve, and adapt – Layman’s point shows there is more we can do on that front.