Cities need Goldilocks housing density – not too high or low, but just right
The trend for elite towers that reach ever skywards isn’t healthy for a sustainable community or for a balanced quality of life
Lloyd Alter, theguardian.com, Wednesday 16 April 2014
In London, Boris Johnson brushes aside opposition to a new development scheme at Convoys Wharf that might threaten the remains of the Royal Dockyard at Deptford. He says: “We need to build thousands of new homes in the capital and proposals to do that at Convoys Wharf have stalled for far too long.”
In Toronto, where I live, theatre impresario David Mirvish (whose dad owned the Old Vic) is knocking down four designated heritage buildings to build three 85-storey Frank Gehry towers. But as Chris Hume of the Toronto Star notes, “There are two types of heritage, let’s not forget: one we inherit; the other we bequeath.”
In New York, sleek new towers for the tenth of the 1% are rising through previously sacrosanct height limits. These are hugely expensive to build, but get such high prices that there seems to be no limit to how high or how skinny they can go. Critic Michael Kimmelman sums up the problem in one sentence: “Exceptional height should be earned, not bought.”
In so-called hot cities such London, Toronto and New York, the planners and politicians are letting a thousand towers bloom. In others such as Seattle, Washington or San Francisco, battles are raging over height limits and urban density, all on the basis of two premises: 1) that building all these towers will increase the supply of housing and therefore reduce its costs; 2) that increasing density is the green, sustainable thing to do and that towers are the best way to do it.
I am not sure that either is true. I am an architect and I certainly consider myself an environmentalist, but it appears to me that in a lot of cities, these new glass towers don’t add much at all to the city in terms of energy efficiency or quality of life. Often they don’t add many more housing units than the buildings they replace. I am also a heritage activist, not because I particularly love old buildings, but because there is so much to learn from them and from the neighbourhoods. and cities that were designed before cars or electricity or thermostats, and were built at surprisingly high urban densities.
There is no question that high urban densities are important, but the question is how high, and in what form. There is what I have called the Goldilocks density: dense enough to support vibrant main streets with retail and services for local needs, but not too high that people can’t take the stairs in a pinch. Dense enough to support bike and transit infrastructure, but not so dense to need subways and huge underground parking garages. Dense enough to build a sense of community, but not so dense as to have everyone slip into anonymity.
At the Goldilocks density, streets are a joy to walk; sun can penetrate to street level and the ground floors are often filled with cafes that spill out onto the street, where one can sit without being blown away, as often happens around towers. Yet the buildings can accommodate a lot of people: traditional Parisian districts house up to 26,000 people per sq km; Barcelona’s Eixample district clocks in at an extraordinary 36,000.
Building tall does not necessarily even increase residential density; in fact, it can do the opposite. In New York’s tall, slender towers, the elevators and stairs take up a huge proportion of the floor space, and there is lot of expensive exterior wall for each unit. The construction costs for this kind of building are ridiculous, and only the very, very rich can afford to pay the price, so apartments are therefore often huge as well; consequently the population density can actually go down.
There is less street life too, as ground floors are taken up with lobbies and exits and ramps instead of stores and restaurants. The great majority of the new projects that are busting through height limits, view corridors and historic districts do nothing to ease the housing crisis and nothing to improve the urban fabric.
At the Goldilocks density, construction is a lot cheaper and the buildings a lot more efficient; in Montreal’s Plateau district, the buildings are mostly just three storeys high, with exterior stairs. Every inch of interior space is used for living, making them almost 100% efficient, and accommodating over 11,000 people per square kilometre. New, greener forms of construction can be used, as Thistleton Waugh did with their 12-storey timber tower in London’s Hackney. In Toronto, architects such as Roland Rom Coltoff of RAW are rebuilding and revitalising neighbourhood high streets with very attractive, modern low-rise buildings, putting the housing where you want it, near transit and schools.
Building to the Goldilocks density is also more resilient: it’s easier to get in and out of your flat when the power goes out when you live on the fourth floor than when you live on the 40th. After Superstorm Sandy, the older walkups in New York’s Lower East Side were reoccupied a lot more quickly than the taller towers with flooded elevators and elaborate electrical systems.
It is not a coincidence that the lower but dense patterns of development seen in Paris, Barcelona and Montreal were built before there were cars. People tended to live in smaller flats, closer together, with narrower streets that acted as their living room, pantry and entertainment centres. They still do today, and as cars are often so inconvenient to park, it is easier to walk or cycle. Not surprisingly, by occupying less space and not driving, they have a lower carbon footprint per capita.
There is lots of room in our cities to do this: not everyone has to live in Chelsea on either side of the Atlantic. New York isn’t even particularly dense, at 2,050 people per sq km, even less than Toronto’s 2,650, which is half of London’s 5,100, which still puts it only 43rd on the list of densest cities. They’re just spiky. Get out of the hot spots and a there’s lots of room to grow.
Economists such as Ed Glaeser would flatten neighbourhoods like Greenwich Village and fill them with 40-storey towers, claiming that increased supply will lower the cost of housing. Economist (and Economist correspondent) Ryan Avent says much the same thing, noting that nimbys use zoning rules, historical designations and public pressure “to preserve neighbourhoods, views, and buildings they love from changes they fear”. They would let Adam Smith and the law of supply and demand decide how our cities are built.
The key to building a healthy and green city isn’t putting wind turbines on the roof of a glass tower; the way to solving our housing crises isn’t handing the keys to the planning office to a bunch of living and dead economists. It is to build walkable and cyclable communities at the Goldilocks density: not too high, not too low, but just right.
Lloyd Alter is managing editor of TreeHugger.