Brandon Donnelly — Daily insights for city builders. Published since 2013 by Toronto-based real estate developer Brandon Donnelly. — Page 99

Vietnam has a building typology known as tube housing.

It is characterized by narrow building frontages, often in the range of 3 to 4 meters, and multiple skinny levels. From what I've read , tube housing first appeared in the 17th century in cities like Hanoi. Its ubiquity over the years, however, has been aided by a myriad of factors, including Vietnam's transition from capitalism to socialism. This change meant that far fewer apartment buildings were being constructed, and so households had to take matters into their own hands and build what they could.

I've also read that this building type may have something to do with the way properties were taxed based on their frontage rather than their site area, though I haven’t been able to find a reliable source for this. Whatever the case, the end result is exactly what we discussed in this recent post — The 9-Step Rule: Why Simple, Narrow Buildings Are Good for Cities . Except with these frontages, it wouldn’t even take nine steps if the average building width is closer to 3–4 meters.

What is equally interesting about this housing type is that it represents a ground-up intervention (as opposed to the result of top-down urban design) and it is highly adaptable. It is not uncommon for additional floors to be added to these tube houses as needs change, and for the ground floors to serve as garages, living rooms, thriving commercial spaces, or as all three at once . It is an entirely flexible space that fuels entrepreneurship and allows households to make money.

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Just think about how much easier it would be to open your own shop if you already owned the space. Conversely, how many of these ground-floor businesses wouldn’t exist if only there were a single line in the zoning regulations that said: “Nah, sorry, you can’t start and operate your own business here.” That is what I often worry about when it comes to land-use policy: what human potential are we quashing as a result of our decisions?

Earlier in the week, I came across this tweet about Paris: "Haussmann cracked the code on what makes a beautiful medium-density city. Why is it then that we can't replicate this all around the world? Genuine question." This is a topic that is near and dear to this blog, so I thought we should discuss it.

But before we can answer this question, I think it's important to ask whether it's even fair to call Paris a medium-density city. Paris is generally considered to be the densest city in Europe. Most sources peg Paris proper (inside the Boulevard Périphérique) at around 21,000 people per km². However, there are areas that reach over 50,000 people per km² , which is dense enough to rival any big megalopolis. So, from my perspective, I would not classify Paris as medium density.

It's a high-density city.

The primary reason why this feature is so often overlooked is likely because the buildings aren't very tall. People see mid-rise buildings of 6–8 storeys and automatically assume that these must translate into some form of a medium-density city. But this is the height–density fallacy. The two do not necessarily correlate. Paris is an example of a high-density city with mid-rise buildings. But I also can think of many low-density cities with high-rise buildings.

Another reason I suspect Paris's high urban density is often missed is that it's also a highly livable and loved city. It doesn't feel that dense (even if living spaces are compact and expensive). The term density can also carry negative connotations for some. Paris, high density? It can't be. But that just helps to prove the point that density is good. You can't have urban vibrancy without it.

All of this gets at one part of the answer to our original question. Paris is not more widely replicated because building height is only one aspect of the Parisian model. Paris is not mid-rise buildings transitioning down to single-family houses. Paris is not mid-rise buildings in only designated areas. Paris is mid-rise buildings everywhere — and at very high densities.

Not every city is prepared to do that. But if you truly want to emulate Paris, then that's what it will take.

My internet friend (and fellow Penn alum), Bobby Fijan , is a strong proponent of more family-friendly housing in urban centers. And by strong proponent, I mean that he is both building more family-friendly housing as a developer and publishing thoughtful research on the topic. His most recent project is this study , which surveyed more than 10,000 people, and looked at what it will take to build more urban homes for young families.

What he and his co-author Lyman Stone found is the following:

• People who don't have enough space at home are less likely to have children.

• Apartments are a growing share of new housing in the US, but they are becoming increasingly less family friendly.

• Americans are willing to pay more in rent per square foot for the same amount of space if there are more bedrooms.

• Developers are not properly accounting for the higher vacancy and turnover associated with smaller apartments (especially in the current market environment).

• Cities could increase the number of family-friendly apartments if they did things like exempt them from FAR calculations, accelerate approvals/permitting, and so on.

This is a topic that I feel similarly about. I am an urbanist and I believe that cities are at their best when they provide for every generation and demographic segment. It's also not a new topic for cities like Toronto.

But I do think cities like Toronto and Vancouver are a bit unique. If you look at some of the floor plan examples in the report , you'll find one-bedroom apartments at 750 square feet and two-bedroom apartments at 1,100 square feet. Part of the thinking is that these floor plans could accommodate additional bedrooms in order to make them more family friendly (and it would be accretive to developers based on the above finding).

But by Toronto standards, these would be very generous apartments. At 750 sf, it is likely the apartment would already have 2 bedrooms and possibly even a den/office. The reason for this is that affordability has been strained for a long time in this city, and the market responded with shrinkflation. Every square foot has already been optimized.

So if we truly want to encourage more family-friendly apartments, I believe that we are going to need to change the cost structure underpinning the development of these homes. In other words, we need to make them cheaper to build so that more families can afford a bit more space. The way you start to do this is by doing some of the things listed in the last point above and by reducing added taxes and levies.