Thursday, July 21, 2011

Blocks of New York

Picking up on the topic of block dimensions and street widths from where commenters left off on Monday's post, I thought I'd share what must be the strongest statement ever made on this seemingly pedantic topic, made by architect Ernest Flagg in 1894:

"The greatest evil which ever befell New York City was the division of the blocks into lots of 25 x 100 feet.  So true is this, that no other disaster can for a moment be compared with it.  Fires, pestilence, and financial troubles are as nothing in comparison; for from this division has arisen the New York system of tenement-houses, the worst curse which ever afflicted any great community." -The New York Tenement-House Evil and Its Cure
A bit overblown, but Flagg had a point.  The fundamental problem was twofold: at 100 feet long, such a lot did not permit interior rooms of a tenement to have windows if walls were shared, yet, at 25 feet wide, there was not sufficient space to create meaningful side setbacks.  The chronicle of New York's tenement laws from 1879 to 1901 shows an attempt by the city to mitigate the effects of these dimensions, which, it turns out, had been chosen by the city's own hand-picked team of commissioners in 1811 as part of the broader grid plan for New York.

And why, after all, had the commissioners chosen blocks of these dimensions?  It can't be known with certainty, but in the 1807 state law empowering the commissioners, the New York legislature (at the urging of the city) had set forth certain planning requirements: 1) that no street be less than 50 feet wide, and 2) that once the commissioners had drawn up their plan, no new streets would be opened through city blocks.  The reason for these regulations seems to have been in part, according to surveyor John Randel Jr., to "[avoid] the frequent error of laying out short, narrow, and crooked streets, with alleys and courts, endangering extensive conflagrations, confined air, unclean streets, &c."

A prohibition on alleys, however, required that all blocks be fairly narrow, since interior block space in wide blocks, without alley access, would be distant from the street and have little economic value.  But the commissioners could not go too narrow either: due to the minimum street width requirements, a city with square blocks much less than 200' would have as much as 50 percent of its land area occupied by streets – a poor outcome for commissioners concerned with maximizing the amount of land for sale to private buyers. 

The resulting blocks of 200 x 800 were therefore an awkward compromise, as an attempt to keep blocks narrow enough such that the amount of inaccessible interior block space was minimized, while maximizing the ratio of buildable to non-buildable area by stretching the blocks out lengthwise.  In no other American city are similar blocks found, possibly due to the fact that in all, or nearly all other cities, alleys were not prohibited and could be called upon to open up overly large grid blocks.

San Francisco street map, showing narrow streets bisecting
grid blocks and reducing block widths to 150' and in some
cases as little as 100'.
Following the establishment of the initial plan, blocks were subdivided into individual lots by property owners, with a common dimension being 25' x 100'. Although Flagg writes that "[w]hen the city was first laid out, the division of the blocks into lots 25 x 100 ft. was entirely unobjectionable," as "people generally built houses of moderate dimensions, lighted at the front from the street, and in the rear from the yard," once land values rose – which did not take long – the deep lot provided a strong enticement to construct houses in the rear, notwithstanding the lack of street access.  Pre-law tenements soon followed, making the most profitable use of the blocks which the city had parceled out in the thousands to private developers.  The lot sizes, moreover, although presumably laid out with a single family in mind, actually contained an inherent bias against single family homes: since a rowhouse might only need 40' or 50' of depth, the creation of lots of 100' length, while prohibiting alleys, essentially made the construction of modest rowhouses an uneconomical proposition.

In the end, the intent of the city to avoid "unclean streets" and "confined air" by banning both new and narrow streets had led, in a lengthy causal chain, to the most filthy, cramped, darkest and least ventilated building type found anywhere in the United States – an urban form so dire that it ultimately contributed to a backlash against the entire notion of a dense urbanism of attached, street-fronting dwellings, and gave inspiration to the tower-in-the-park form which characterizes many or most public housing projects in New York.  The commissioners could never have forseen this outcome, but the lessons, as far as the importance of block and street width, are definitely worth thinking about.

For a some good background on all this, check out Columbia's series on New York apartments here.


  1. "[avoid] the frequent error of laying out short, narrow, and crooked streets, with alleys and courts, endangering extensive conflagrations, confined air, unclean streets, &c."

    Here we have some interesting justifications for wide streets. The first, to serve as a firebreak, is one that we don't much think about today, although we have a similar result in that wide streets are mandated to provide access by firetrucks ... which are themselves designed for wide streets (i.e. very large). In the Traditional City, the occasional larger street (what I call an Arterial or Grand Boulevard) served as a firebreak.

    The others have to do with simple sanitation. European cities have always had sanitation issues, apparently because Europeans just were rather filthy. Japanese cities were known for being very clean, even in the first Chinese records of the 7th century. This is not caused by street width itself, but they saw wider streets as a way of dealing with it apparently.

  2. Nathan: all of the reasons break down upon closer examination. The fire break justification can possibly be used to mandate a few wide streets, as you say, but is irrational when applied to cross-block streets. Would running a 20' street down the middle of a NY block increase the fire risk? No. In fact, it reduces the fire risk by providing additional access routes for fire equipment. This is true for almost any subdivision of a larger block by small streets.

    Confined air has little to do with street width and everything to do with building design, the placement of windows, etc., which is also related to parcel dimensions. The street width requirement ultimately encouraged the design of buildings with insufficient light and ventilation -- it would not have mattered whether they faced onto 15' or 100' streets.

    As for cleanliness, it seems logical that a smaller street should be easier and quicker to clean than a very wide street. The example of Portland shows how these wide streets quickly became filthy, muddy quagmires, as it was too expensive to pave them. Why this was seen as a "cleaner" alternative I'm not entirely sure.

  3. Today I read this history of tenements and apartments in New York, by Andrew Dolkart:

    It also contains that quote above about 25x100 foot parcels.

    Dolkart notes that in the late 1800's there was widespread belief that clean, cool air would cure tuberculosis. Some model tenements had balconies to allow people with TB to lie outside in the night air. Of course we now know the bacterial source of TB, and access to fresh air isn't the issue.

    But considering that back in those days, tenements were for the sick and dirty poor, and the healthy, prosperous rich lived in country houses with plenty of windows and space, it was easy to think that the lack of "light and air" in traditional cities was the cause of social and health problems.

    Now that apartments in old law tenements (from the late 1800's) rent for $2500 for a 1 bedroom (example:, I don't think there is any stigma against these places. Electric lights, air conditioning, running water and fireproof construction make the old arguments invalid.

  4. Thanks for commenting, Joseph. The explanation for TB was a mistake; however, even if it had been correct, my point was that the street width regulations did nothing to ensure access to fresh air anyways, so even on its own terms it was not a success. Mandating wide streets was an easy substitute for critical thought about urban form (the thing Flagg's essay is concerned with, in great detail).

    It's true that the apartments have become desirable today, although it has required occupancy to fall dramatically such that, as I tried to show the other week, the old "tenements" now have a population density comparable to single-family rowhouses.

  5. Charlie, you should read The New York Rapid Transit Decision of 1900, from the Historic American Engineering Record. Reformers like Flagg were effectively agitating against the communities formed in the slums (typically ethnic, i.e. not fully American according to the Progressives), but framed their arguments in terms of urban form. That this sort of proto-urban renewal progressed in the same manner in New York and London should be enough to dispel the notion that slum clearance was truly a question of the city's urban form.

  6. Alon -- thanks for that. I can't claim to know what Flagg's precise intentions were in writing this piece. It's possible, or likely, he shared the attitudes of the time as to the "slum dwellers," but I do not think this article really reflects that. He seems to be genuinely troubled that the construction industry mindlessly replicated 25' x 100' tenements when, by combining two, three or four lots, the same amount of square footage could be built at lower cost and with far greater exposure to natural light (the concern with keeping the square footage constant seemingly indicating that he did not view density itself as problematic, but simply the way it was arranged). Given the attention to costs and designs, the intended audience seems to be financiers, builders and architects, not politicians and social reformers. And even if it was all an elaborate pretext, I think his argument stands on its own.

  7. Oh, the argument certainly stands. Flagg himself almost certainly believed in what he was saying; the patrician reformers (who included the various technical experts of the time) truly were horrified by the slums, but could not bring themselves to propose reforms that were too socialistic. It's the same mindset that created auto-oriented suburbia, when the subways failed to produce the desired sprawl. If you ask me the same mindset is going on today, only the reformers have done a 180 and are now proposing mixed uses, managed diversity (what Stuff White People Like mocks as "much needed diversity with people who are, for all intents and purposes, exactly the same as them"), higher density, and TOD. That's why I keep writing blog posts warning that the US is becoming like France.

    On the specifics relevant to this post, the 20'*100' tenement block was favored in New York in the middle of the 19th century, as an alternative to squatter homes and Five Points tenements. New York spent the period roughly from the 1850s to the 1890s enforcing property owners and landlords' claims against squatters, rejecting adverse possession claims often on flimsy grounds. It also demolished Five Points, partly for hygiene reasons (Canal Street was awful) and partly for social ones (it was a slum); this is what created the Lower East Side familiar to everyone from stories of tenement hardship.

  8. I agree with Alon that a lot of urban design choices were made as a result of dealing with problems that were not really design-oriented in the first place. Wider streets to deal with sanitation issues, for example, which were really a matter of trash collection, sewage, drainage, and also just personal habits. Today's "slums" in Brazil and elsewhere, Calcutta (Kolkata today) or Kinshasa for example, are actually rather nice examples of emergent Traditional City patterns, however with all of the problems of poverty and insufficient utilities (sewage, trash collection, water etc.) New York's tenements of the 19th century were rather horrible, but the tower blocks of the 20th Century, into which the poor were moved, haven't been much better. In the meantime, those horrible 19th century tenements, despite their design flaws, have become rather desirable one-bedroom apartments for young professionals and rent at $2500+ per month. For some reason, poor people in the U.S. have a self-destructive tendency, which results in them living in self-created squalor, instead of using their limited means to make the most appealing living spaces possible. Just ask anyone who is a landlord to Section 8 tenants.

  9. Alon: interesting thoughts on this. I've been trying to find out a little more about Flagg, and it seems he was a vociferous critic of the 1811 Commissioners' plan from a Beaux Arts point of view -- the very type of aesthetics-oriented perspective that earned the scorn of 20th century progressive reformers. One source calls him a "confirmed individualist." Clearly there's some overlap with the reformers of the time, but he doesn't appear to have been suppressing socialist leanings. He was, after all, proposing a market-based solution to a perceived failure in government planning.

    Nathan: The buildings Flagg was proposing were in between the "old law" tenements and the 20th century tower blocks -- these "new law" apartments were built throughout Washington Heights and the Bronx, and sporadically throughout the rest of Manhattan (but especially in the UES and UWS). The earliest public housing projects (1930s) imitated their form, before spinning off into either low-rise garden apartments or the tower-in-the-park format.

  10. Fascinating!! Thank you.