Reassessing the Street-in-the-Sky in Times of Coronavirus

As Covid 19 spreads its way around the world, a fear of urban density is similarly catching on, with suburbs, exurbs, the countryside, and even oceanic floating colonies being posited as possible solutions for limiting contagion. Sound familiar? It’s certainly not the first time the city is becoming viewed as an “evil”. In the 18^th century, London’s nascent bourgeoisie began to feel that the metropolis was no place to bring up children, what with all those business dealings going on in the home, so they moved to the countryside, where they started to emulate the aristocracy, and started commuting by horse and carriage to a place of work now separate from home. Later, in the 19^th century, the reason to move out of cities was precisely to get away from the pollution emitted by the very factories the bourgeoisie was busy building, which the invention of the railway and the streetcar made possible. Then, in 1950s post-war USA, the government encouraged the construction of suburban settlements by guaranteeing affordable mortgages (G.I. Bill) and by building urban expressways on which to drive a V8 downtown; expressways that destroyed inner city neighborhoods inhabited mostly by African Americans and Latinos. Today, the reason for fleeing the city en masse is different yet again: a deadly virus that is easily caught in crowded places. Office buildings around the world sit largely empty, as many of their workers are staying home and teleworking; the same for universities and schools. The safest place is the home, and even that can be risky if things like communal stairwells, elevators and entrance lobbies have to be physically shared with neighbours.

The house with its own front entrance is once again the ideal model of domesticity, but is low-density suburban sprawl the only kind of “urbanism” that can provide it? Do the many advantages of urban density necessarily have to be given up for this kind of housing model? The current pandemic panic is making us forget that we are also living through another deadly emergency, albeit one that strikes randomly (or through “acts of God” if you’re religious) in the form of wildfires, droughts, and extreme weather events such as hurricanes and floods. Sprawl, with its automobile dependency, is an important contributor to climate change, but it is also behind the emergence of deadly viruses, since (as some scientists believe) these are transmitted to humans from wild animals such as bats whose natural habitats are being encroached upon. In reality, the safest place to live from the point of view of both dangerous viruses as well as climate change is a city. 

The question that should be asked, then, is which urban residential building types perform best when it comes to minimizing the transmission of deadly viruses. It’s certainly not typologies whose circulation systems are deeply embedded within the interior of a building, such as the typical apartment building whose flats are accessed by way of interior stairwell landings (typical in Europe) or long, double-loaded corridors (typical in North America). Buildings with outdoor circulation systems such as balcony walkways, access decks, or porticoed galleries are a typology that is interesting in this regard. Unfortunately, however, such access systems fell out favour after several failed housing projects from the 1970s employed them.

Access decks became a feature of many 1960s and 70s megastructures after architects Alison and Peter Smithson portrayed a “street-in-the-sky” in their scheme for the Golden Lane housing competition of 1953. Habitat 67 in Montreal, for example, by Moshe Safdie, the slogan of which is “for everyone a garden”, has outdoor access decks in a city that sets world records for annual snowfall; but then Montreal also has a curious vernacular tradition of stacked dwellings reached by exterior stairs ascending directly from sidewalks.

Habitat 67 is considered an upstanding address, but many other housing megastructures are not, precisely because streets-in-the-sky became ideal places for street-gangs. A Clockwork Orange, Stanley Kubrick’s 1971 film adaptation of Anthony Burgess’s dystopian novel, which used Thamesmead estate near London as a location, articulated a public fear and loathing of megastructures at that time.

However, access decks are much older than the brutal and brutalist megastructures they are widely identified with. The 17^th century corralas of Granada or Madrid, for example, never became notorious for crime even though they contain access decks, here in the form of porticoed galleries around courtyards.

So why did the megastructure’s street-in-the-sky become so despised? The question literally answers itself: the access decks of megastructures tend to be very long, serving many dwellings. In the case of Amsterdam’s Bijlmermeer or Rome’s Corviale (pictured below), the walkways reach 500m and 960m in length respectively.

When a single walkway serves too many dwellings, neighbours don’t feel that they have communal ownership of that space, whereas if walkways are relatively short and used in relatively small or medium-sized housing projects in which neighbours are more likely to be familiar with one-another, then this problem is less likely to emerge. Indeed, outdoor access decks can even become spaces of communal sociability if they are designed well.

Interestingly, outdoor walkways need not be limited to low or mid-rise buildings. The tallest building with outdoor access that I am aware of is the 27 story tall Renaissance Fira Hotel near Barcelona, by Jean Nouvel; the luxurious suites of which are accessed by outdoor walkways that overlook a dramatic vertical void filled with vegetation. Of course, exterior circulation won’t work on buildings much taller than that for reasons of safety, comfort, and economics, so it is definitely ruled out for skyscrapers. But then 27 stories is plenty tall and monumental.

Cromwell Buildings are noteworthy for being among the smallest stacked dwelling typologies to use outdoor access decks. These privately built affordable housing projects were a notable success, with many built throughout the UK. The one below is in Southwark, London, and dates from 1864. Serving no more than three flats per floor, its exterior access system forms a unique feature of its front façade.

Having sufficient width for dwellers to keep some potted plants on communal walkways helps with sociability. But if the deck is very generously proportioned, it can even become a recreational space. Rotterdam’s Spangen social housing project of 1921 by Michiel Brinkman features a genuine street-in-the-sky avant la lettre: it was designed to be wide enough for a milkman’s delivery cart to make its morning rounds. One of the most inventive modern housing designs of the 20th century, this typology works well because privacy is not compromised, enabling communal sociability to occur voluntarily.

Another early modernist housing project of interest is Edwin Lutyens’s Grosvenor estate in Westminster, London, from 1930. Not unlike the Spanish corrala, the orientation of communal access balconies around a communal courtyard makes the latter theatrical, if not operatic; a veritable amphitheatre for the spectacle of everyday life. Note the rigour of the floor plan, as well as the staggered pillars supporting the galleries.

The lesson, then, that this brief study of street-in-the-sky precedents can teach is simple: keep outdoor access decks communal instead of completely open to the public, and keep them short and sweet, without too many flats sharing them. Small is beautiful indeed.