Wednesday, March 8, 2017
So, I've recently discovered an interesting tool to visualize census data for Canada, www.censusmapper.ca. Among its various data, it allows to do visualization of population density bloc by bloc (rather, census tract by census tract, but most of them are bloc-sized). This made me want to do a kind of encyclopaedia of density, for typical forms of development in Québec, and maybe a bit from Canada too.
Why Québec? Because I live here and Québec has a special focus on low-rise developments lacking in a lot of North America. I may do one for American developments one day, with city-data providing a similar tool to explore population density bloc by bloc in the US.
Before going on, I'd like to point out a few things.
First, there is the question "is there a density threshold for walkability?". This depends on a lot of factors, and my own thinking on the subject has led me to doubt that residential density is even the most important factor. Overall, though, I tend to consider that local walkability is highly dependent on access to a modern supermarket, the most important and frequently visited store for most people, of which there tends to be about 1 per 8 000 to 12 000 people in North America and a 10-minute "walkshed" is about 1 kilometer big. So a walkable neighborhood, supposing a good design that maximizes walking speed, should have 8 000 to 10 000 people per square kilometer. Which comes down to 80 to 100 people per hectare.
Around here, people also suppose that the minimum density to support high-frequency transit is about 35 dwelling units per hectare, which would be about 60 to 80 people per hectare.
Oh, and a quick summary for units.
4 people per acre = 10 people per hectare = 1 000 people per square kilometer = 2 560 people per square mile
I'll use people/units per hectare in the following.
OK, so let's get started.
50 to 70 people per hectare
30 to 40 dwelling units per hectare
This is an old type of chaotic developments common to old villages, with small detached single-family homes living alongside semi-detached homes, duplexes and other low-rise multifamily buildings. What characterizes it is the lack of uniformity, neither building line, nor architectural style, nor building function are uniform. This is the orderly chaos of developments pre-zoning.
40 to 50 people per hectare
15 to 20 dwelling units per hectare
This is a form often seen in older suburbs, a transitionary period between the chaos of early villages and the strict planning of today's cities. Lots tend to be about 15m x 30m (50' x 100'), front yards are more common, rear alleys are extremely rare.
55 to 70 people per hectare
25 to 35 dwelling units per hectare
This is present in some older suburbs that were built before strict single-use zoning came about and that had a mix of homes and low-rise apartments. As a result, zoning in these areas often allow both single-family and multi-family uses, even today allowing for the replacement of old houses by small condo buildings. In a way, this is very similar to the old village mix, simply with a more orderly design, with a clear building line, for instance, with front yards and more regular spacing between buildings. Density is consequently very similar between the two. Still the density here is not quite up to par with highly walkable cities, it's a bit too low but it's pretty close and it can justify adequate transit options. When they were built, people tolerated smaller stores and more crowding per unit, so these were highly walkable then.
55 to 60 people per hectare
30 to 35 dwelling units per hectare
The duplex is perhaps one of the most common types of buildings in traditional Québec towns and villages, especially the squarish duplex with exterior stairways, balcony and porch. Uniform streets of these are relatively rare, but they exist, like this neighborhood in Trois-Rivières. The density here is still at or a bit below the threshold for minimum density. Traditional duplexes allowed people who couldn't afford single-family houses to afford housing by building a second story and renting it out, creating revenue that allows the owner to afford his own unit. Duplexes also allow for more air and light for every unit, with side windows made possible by each building being built apart from one another and separated by a few meters. This also allows for 1 or 2 parking spots to be built per unit, so even if you're in a car-centric city, this form of development is viable, all without violating some people's low-rise sensibilities.
60 to 90 people per hectare
50 to 70 dwelling units per hectare
Standalone triplexes aren't rare in older towns, but it's rare to have blocs full of them. Shawinigan, a small town north of Trois-Rivières is one of the rare cases I know of where this is a dominant typology of its older neighborhoods. The population density could be higher if it weren't for the fact that this city is in demographic decline and so housing is cheap, allowing singles to rent big apartments. I'm not kidding, I checked the rental ads for the town, you can get a 3-BR apartment in one of the buildings on the picture for 400$ a month. Anyway, if properly occupied, this typology would easily be favorable to walkable cities and good transit. Also, contrast this image with the previous one to see the impact street trees have on the beauty of a street.
120 to 150 people per hectare
60 to 75 dwelling units per hectare
This is mainly seen in major cities that had streetcar suburbs. Montréal has neighborhoods with this typology. It's a bit similar to the previous duplexes, but instead of being squarish detached structures, these are deeper than wide and built wall to wall. Otherwise, the concept is the same. Since side spacing is eliminated, it allows for essentially a doubling of density. We are well in the territory of the walkable city here, and indeed neighborhoods with this typology in Montréal are associated with strong neighborhood stores, high walk scores and low (30 to 50%) car commuting mode shares.
190 to 220 people per hectare
90 to 120 dwelling units per hectare
This is like the previous case, but instead of being limited to 2 stories, you have 3. Obviously, this results in a 50% boost to density and creates very high density. This doesn't provide more parking than the attached duplexes of the previous example, while density is boosted. So it won't satisfy suburban parking requirements and it will yield lower car mode shares, simply because it's next to impossible to maintain universal car ownership due to the lack of parking spot. Many Montréal neighborhoods include a mix of 2-story and 3-story attached buildings, and have density between these two examples of uniform duplex and triplex developments.
200 to 280 people per hectare
120 to 150 dwelling units per hectare
Yes, these do exist in North America. Very rare, but you can find them in the Vieux-Québec area of Québec City. Tightly packed 2- and 3-story buildings with high lot coverage. Very high density, very few parking spots and narrow streets. Nice to visit, more debatable how nice to live in considering the proximity of buildings both in front and in back.
These are developments made since the advent of mass motorization, often, but not always, with parking. These developments often incorporate modern construction techniques, whereas the traditional developments didn't.
25 to 30 people per hectare
10 to 13 dwelling units per hectare
This is the usual sprawl-type development in suburbs all around Québec. Generally wide (20m x 35m) plots with wide 1-story houses (with livable basements) and driveways. Density half to a third that of traditional villages and even 30 to 50% less than earlier single-family suburbs. Far from density thresholds for walkability and for transit services.
60 to 80 people per hectare
45 to 60 dwelling units per hectare
This is a type of low-rise apartments often built in suburbs. Some are apartments for poorer residents, others are more upscale for the middle class and sold as condos. They offer similar density to tradition isolated duplex neighborhoods or traditional village mixes, but offer a lot more parking. They also have bigger setbacks and thus maintain air and light in a way that is tolerable for the suburban-minded. As they tend to have little or no underground parking, instead opting for parking lots, they are quite cheap to build.
100 to 120 people per hectare
80 to 90 dwelling units per hectare
This is more or less the maximum density you can get while respecting suburban parking requirements without getting into mid-rise or high-rise territory and without resorting to massive underground parking to keep costs down. This density is sufficient to provide for walkable neighborhoods and to sustain transit lines. However, the quantity of parking lots they generate reduces the desire to walk and makes it easy for people to opt to own and use cars.
140 to 160 people per hectare
55 to 65 dwelling units per hectare
This is essentially the traditional attached duplex neighborhood adapted to the car era, with slip-under, front-loading garages to satisfy parking requirements. The result is that they retain the old duplexes' density, but at a cost of comfort to walk and of street design. The massive driveways mean frequent curb cuts making walking less comfortable and reduces trees and grass to a minimum, making the area less hospitable to human beings. The number of units per hectare here isn't all that high, but the location of these buildings near Montréal, the size of the units, the private door and the back yard all result in a high number of occupants per unit, and thus higher population density than the isolated low-rise apartments in the two previous types.
100 to 130 people per hectare
40 to 45 dwelling units per hectare
This is a rare form of modern townhouses present in a few areas. Its modernity is not just in its architectural style, but in the parking present below the back yard's porch, with a driveway sloping down between each group of townhouses. This is an innovative attempt at reconciliation of the car-centric development but with an urban face, limiting curb cuts and preserving front and back yards while still offering at least one parking spot in a garage per house. However, it's not particularly affordable and its design over 4 stories (basement, 1st floor, 2nd floor and 3rd floor) means a lot of stair-climbing for every member of the family. No need for a Stairmaster with a house like that.
330 to 380 people per hectare
140 to 160 dwelling units per hectare
I wasn't sure whether I should have included this in traditional or modern developments. On one hand, its architecture style is reminiscent of the duplexes built over garages and there are some driveways and garages present, at the same time, it clearly offers way less parking than most other modern developments. Anyway, this is, as far as I'm aware, the densest low-rise area in Montréal, located in Parc-Extension. These are effectively 4-story buildings as the basement has units too. It's also a particularly poor area, populated by recent immigrants for the most part, so it has higher than average number of occupants per unit.
350 to 500 people per hectare
250 to 300 dwelling units per hectare
This is a form of planned condo development on old disaffected industrial grounds. The planning is very evident and show bloc-sized planning, with huge garages in the interior of the blocs being covered by parks for the enjoyment of the residents, though the park is not visible from the street as it is elevated a couple of stories up. The high cost per square foot and deep building results in a very high amounts of units, as most of them are studios or 1-bedroom apartments. It's good density but that doesn't help life on the street as much as previous eras duplexes and triplexes.
800 to 1 200 people per hectare
500 to 800 dwelling units per hectare
I couldn't avoid mentioning the highest density blocs of Montréal that I know. These are high-rise apartments located near Concordia university in downtown Montréal. These are not only high, they have pretty high lot coverage, for a very high population density. This is the kind of development you can barely imagine anywhere else but there, to satisfy student's requirements for housing. The use of the ground floor for retail and restaurants also helps attract and retain people to the area, unlike the pretty sterile modern condos shown in the previous type.
So here you go, an overview of densities present in Québec, from traditional villages with isolated buildings to modern developments. This can provide a good idea of the possible ways to achieve a density that is sufficient for walkability and transit use, and how high-rises are not necessary to achieve sufficient density.
So this was a description of some housing typologies found in Québec, both traditional and modern. But Canadian cities can be a bit different, they're more like American cities in some ways, often with a focus on single-family housing and bigger tenement buildings.
45 to 60 people per hectare
20 to 25 dwelling units per hectare
For anyone who knows American small towns, this is nothing new. These are detached homes built close to one another but not sharing walls, on narrow but deep lots, a typology of urban housing extremely common in anglo North America. The density isn't quite high enough for walkability today, but once upon a time, you could have expected many of these homes to have taken in boarders. Today, this is extremely rare and families are smaller, so population density is probably much lower than 100 years ago.
80 to 100 people per hectare
35 to 45 dwelling units per hectare
This is just a denser form of the previous, with even narrower lots and homes nearly touching, with barely enough space for a man to walk between them. The density here is similar to Japanese single-family house neighborhoods and is actually sufficient for a walkable neighborhood and adequate transit services.
100 to 130 people per hectare
45 to 55 dwelling units per hectare
This is the traditional form of development in Toronto, the equivalent of Montréal's duplex neighborhoods, except instead of relatively wide duplexes on shallow lots, these are detached and semi-detached homes that are very narrow on very deep lots.
60 to 100 people per hectare
15 to 30 dwelling units per hectare
Just like Montréal has duplexes built over garages which are an adaptation of its traditional duplex type of housing, anglo-Canada has a modern adaptation of the old narrow and deep urban home... the snout house. Thus named because of the protruding garage doors that look like a snout and reduces front-facing windows to a minimum. Note that the population density here is uncommonly high considering the number of dwelling units. We're approaching 4 people per household on average, versus 2,5 on average in Québec single-family housing. I don't know why that is, but that ratio is high all across Mississauga, at least, in that area. Is it an ethnocultural community that has unusually high fertility rates? Is the price of housing pushing people to live with their parents and children longer? I don't know.
110 to 130 people per hectare
70 to 90 dwelling units per hectare
This is a relatively rare case of an old type of density in an old Anglo-Canadian city (Hamilton). As the lots are narrow and deep and buildings are detached, you can see some areas where, among the old urban homes, you can spot narrow and long apartment building 3 to 6 stories high. However, this process seems to have been interrupted by the arrival of modern zoning practices and parking requirements. It's interesting to note the difference between low-rise apartments in Québec and in Anglo-Canada, with Québec having small low-rise apartments built wall to wall, often owned by one of the occupants, without the need of a lot of capital to own it, and Anglo-Canada having bigger apartment buildings that were probably owned by richer owners who resided somewhere else.
250 to 400 people per hectare
200 to 300 dwelling units per hectare
I know of nothing else that can showcase the lack of middle housing in Anglo-Canada than this. High-rise apartment buildings carved out of old neighborhoods of urban homes, resulting in 2-story urban homes being next to 20+-story apartment buildings with underground parking. This is probably the stuff of nightmare of most NIMBYs... and even of a ton of urbanists, I suppose. I would be curious to know the value of the remaining homes next to the high-rises, to see if their value is higher or lower than similar homes a bit further away, just to test the theory that high constructions depress the value of neighboring low-rise single-family properties. Anyway, very high density nonetheless, almost Paris-level density in some areas.
500 to 800 people per hectare
350 to 500 dwelling units per hectare
Vancouverism is the name used to describe the style of development that forms the basic pattern of Vancouver's downtown. Funnily enough, it's not unlike the previous chaotic development in Hamilton in that it combines low-rise and high-rise developments on the same bloc. The difference is that Vancouverism is more ordered than what we see in Hamilton's central neighborhood, building lines are more respected, the placement of the skyscrapers resembles a checkerboard, to prevent buildings from cutting light and air access to one another and to avoid a trench feeling for people on the street. The density level is probably among the highest in the Western world, equaling or topping the dense neighborhoods of Barcelona and Paris. This is Manhattan Upper East Side levels of density. The main issue of such development is cost, as skyscrapers are not affordable to build at all. Vancouver's out of control housing market makes such development possible, but that may not be the case everywhere.
OK, so this was just a catalog of density of different development patterns seen in Québec and the rest of Canada. I don't claim this list to be exhaustive. I think it may be useful to have such a catalog to know what different levels of density look like and to lay to rest some ideas. Thus, both the idea that you HAVE to go very high to achieve walkability-supporting density (when even 2-story developments with detached buildings can approach that threshold) and that there is no point to go very high because lower lot coverage means you won't get more floor space are wrong.