Heights and Streets

 Well, since there seems to be some further chatter about optimal density in the air, this seems like as good a time as any to address some thoughts I've been having regarding streetscapes and density, particularly in terms of height. 

After all, height is a key to density in urban space: rowhouses are only so dense if they are still one story (and you can get a lot more density from buildings further apart if they're taller as well). But also density is key to density: that spacing is also critical. So what works?

1. Consistency is Key

One of the elements that I think the article I linked above does a really good job with is the idea that we're not necessarily talking about every building being the same size or shape (that's a different kind of urban form anyway), but we are talking about the default background of the city being consistent--and consistently dense.

The far side of this street in Amsterdam, for instance, is pretty much the same design (though you can definitely tell where each building starts and ends from coloration and decorative details) but the close side has clearer variation (though I'm sorry about the photo, which did not capture that as well as perhaps it might). The general overall sense of the built environment here is consistent though, on both sides of the street, even if there is more color and material variation on the closer side.

Likewise, this Parisian street scene has more variation (it's not literally all the same height) but a general consistency of size, if not appearance: it's all in the 3-6 story range. Nothing is short (no single family homes) and nothing is huge (no 8+ story buildings standing out). 

That consistency is key both for a coherent urban form and for efficient use of land.

This is especially true if you have narrower streets, as in the above London picture--which again showcases how consistency of size does not have to mean uniformity of building material or appearance.

You can have an interesting, varied city without having to radically alter heights--although I do want to emphasize that I quite like the left side of the street in that first Amsterdam picture too. There's nothing wrong with attractive consistency in appearance as well!

2. Width and Spacing Matter Too

Relatedly, the width of the street and the spacing between houses/apartments/buildings/etc. is also key to effective and consistent density.

Gazing across the Thames at St. Paul's Cathedral we have a natural experiment in heights: due to regulations of St. Pauls views, none of the buildings in front of it can be taller than it, or even rival it. But they're sitting on extremely premium land in the City and adjacent to it (the City of London, that is, the square mile at its heart, not just Greater London). So they want to get maximum value out of their parcels--which means that you can see very little space between the buildings.

That closeness can be key to density in an overall urban setting.

Take this shot across Chicago. Ignore for the moment the truly high-flying towers of the dense downtown core, and look at the overall urban fabric: most of the green is deliberate parks, not open space between apartments except where there are a few overdense apartment blocks surrounded by greenery--itself an intentional choice. By and large when you look at a dense, urbanist urban form (and Chicago does pretty well on this by US standards) you see this kind of close together, 3-6 story "midrise" apartment/condo construction.

That doesn't mean that your close together buildings can't have flair: I have concerns about the accessibility to people like my parents of apartments like the above, in Montréal, but they're distinctive and dense at the same time. And they even have a setback from the road to allow for the staircase and the front yard--though it helps that the street here is not particularly wide by North American standards.

To me, the greatest flaw in neighborhoods like Wallingford in Seattle (above), is the combined failure of these two elements: the street is too dang wide and while you can see one little apartment behind the grocery store in the above picture (and another is across the street to the right), the vast majority of what you see is separated single-family housing.

Of course we need to have that in the mix as well. But combining the spaces between houses with the lack of consistent height in the buildings we do have and the width of the roads...they collectively undermine the effective density of the city overall even if each individual plot has something not too bad on it.

3. Background and Variation

Again, the major point of the linked article I want to reinforce and highlight is that we're talking about the basic background of a city. There's plenty of space for variation, be it to parks and other open spaces, to single-family homes, or to high-rises.

This nice midrise part of Croydon is just a short walk from this open space (a park):

The idea isn't to banish parks and open space, but to make them deliberate and communal, rather than haphazardly attached to whatever property you individually happen to possess or occupy.

Likewise, this reasonably dense (if very wide in the street!) section of Chicago is just minutes from these high-rises:

So again, the idea isn't to say "only midrise housing please, get rid of the bigger stuff."

I've been pretty open on this blog about my love for Vancouver-style urbanism, and the mix of high-rise and mid-rise there is one of my favorite elements, for instance. 

It's really about making sure that the basic unit of a dense urban city isn't trying to somehow be detached single-family homes set against a wide four-lanes-plus-parking street. That is an inherently undense form, no matter how much you vary it with high-rises. Those should exist (at least the homes--the roads are perhaps a different question) but they should exist as a variation to a consistent urban emphasis on those 3-6 story buildings that allow for a mixture of density and openness that allows a city to actually house its residents.

Most of the time: it's not like Amsterdam doesn't have (like the whole West doesn't have) a housing crisis. But it's certainly a better start than just single family homes like a typical US design.