Perhaps the two most distinctive features of Montreal's low-rise architectural landscape are (1) lots of exterior stairs and (2) lots of balconies. (Their density is, of course, also noteworthy, particularly in a North American context.)

The exterior stairs are somewhat curious to outsiders given all the snow the city gets. But it's maybe a good case study and follow-up to yesterday's post about 1925 Victoria Park Road and its proposed exterior corridors.

As for the second feature, the Globe and Mail recently published this wonderful little ode to the Montreal balcony. It is a great reminder that, when designed well, people really do love balconies and exterior spaces.

This is an ongoing debate in the world of multi-family development, and the outcomes often vary by city and sometimes by housing tenure. But at the end of the day, I have yet to meet anyone who doesn't appreciate getting outside in the summer.

Hedge fund manager Bill Ackman is a pretty wealthy guy and so it is fairly safe to assume that he could choose to live almost anywhere. For some people the ideal might be a low-rise house with a backyard in the suburbs.

But since 2018, Ackman has chosen a kind of penthouse apartment on the roof of a 1920's co-op building in Manhattan's Upper West Side. It was formerly the home of author Nancy Friday and Ackman supposedly purchased it for $22.5 million.

He is now looking to demolish the penthouse and build a new two-storey residence designed by architect Norman Foster. The design looks like this, which kind of reminds me of Philip Johnson's The Glass House:

Today it was in the news that Ackman has been having a fun time trying to convince his co-op board that a new set of glass boxes on the roof their building is a good idea. FT reported that the project has created "an atmosphere of fear and distrust among residents in the building."

I'm not exactly sure what it is about this proposal that is causing fear and distrust but Ackman is on record saying that he thinks this isn't about heritage preservation or architectural integrity; it's about people not wanting the disruption that comes along with construction. Fair.

One way to test this, I suppose, is to propose something more traditional or similar to what's already there. But I suspect that the other dynamic at play here is simply that he is a rich guy with a starchitect trying to build something cool.

Building things is tough.

London has a breed of specialist developers that are known as rooftop or airspace developers. What these developers do is build on top of existing and occupied buildings -- mostly residential. Firm examples include Upspace and Apex Airspace. According to this recent WSJ article, the city is also making moves to relax regulations so that more of these top-ups can be completed.

Brokerage Knight Frank estimates that in central London alone there are probably 23,000 buildings that could support a few extra floors, resulting in upwards of 41,000 new homes. I have done early feasibility studies for similar projects here in Toronto and they're not simple to execute. But building structures are typically constructed with a factor of safety and so, in some/most cases, you can build a little on top without doing any additional reinforcing. (Note: I am not a structural engineer.)

In any case, the benefits of airspace projects are obvious. You're creating additional supply in a tight housing market like London. Similar to Toronto's laneway housing program, it's not going to completely solve the larger problem of affordable housing. But every bit of new housing helps, regardless of where it lands on the spectrum of affordability.

One of the drawbacks, which is the headline of the above WSJ article, is that penthouse residents are getting demoted in the process. They're going from penthouse to sub, or sub-sub, or sub-sub-sub penthouse. They also need to endure a bit of construction right above them. Cry me a river?

But what is also important to point out is that there are lots of buildings out there which are facing capital expenditure shortfalls. They have maintenance and repair demands that simply aren't adequately funded. Adding additional floors can be a way for these buildings to generate that cash and, in some cases, residents are even partnering with airspace developers to share in some of the profit upside.

Not surprisingly, these sorts of arrangements are seemingly being met with a fair bit of support. Because in these instances, your options are basically as follows: Either you cut a repairs and maintenance check right now or you support a bit of development and then hopefully you'll be the one receiving a check in the future. I suspect we'll be seeing a lot more of this, not just in London, but in cities all around the world.

Photo by Sometimes I Snap on Unsplash