Tishman Speyer, the San Francisco Giants, and MVRDV have just completed a new residential building in San Francisco called "The Canyon."

The first phase of the larger Mission Rock masterplan (which also includes a project by Studio Gang), the complex got its name because of a walkway that cuts through the plinth of the building and that, well, looks like a canyon. You can see it in the above image if you look closely. There are even stairs that take you up as you walk through it.

But what is most interesting about this walkway is not its geological reference. It would be how it performs at the ground floor and for the homes that face into it. It's a way of creating a narrow mid-block connection (and we like narrow streets), while at the same time allowing more light into the center of the block.

So I'd be curious to see/experience what it's like in the middle of this canyon. Hopefully it's interesting.

Photo: Jason O'Rear

This proposal by Dubbeldam Architecture + Design, called Incremental Density, is both an obvious step in the right direction and a problem. It is directionally right because it is exactly the kind of "gentle density" that we need and that many of us hope to see in our cities.

Four to six storeys, prototypically built on an as-of-right basis all across city, possibly by small-scale owner/developers. In fact, this approach is one of the things that Toronto's new mayor, Olivia Chow, has been speaking about on her first day in the office:

Further, Chow said she wants to make it “easy and fast” for those who want to “build up” their single-family, often detached, homes to address what is known as the “missing middle” due to a history of “red tape” around zoning.

“What I’m saying is ‘build, build, build, build,’ up to four storeys if you want to have four units,” she said. “You can rent out three of them and some money right. Then you are creating more housing, and you’re earning some extra dollars,” she continued.

“So I want to unleash the power of the homeowner and say to them, ‘go build it,’ because we need housing right here now.”

Here's the problem, though. I'm going to go out on a limb and assume that at least a few people will not want 6 storeys beside them and their backyard. I mean, I struggled with a 2.5 storey laneway house for many years. (11 to be exact.)

So how do we get from where we are today to what you see above? It's going to take some finessing. Maybe it's only in specific areas and on certain sites to start, or maybe we need to gradually increase the massing over time. Either way, I too am ready to "build, build, build, build."

What do you all think of this proposal?

Images: Dubbeldam

We have spoken before about buildings, such as this 6-storey one in Paris, that were allowed to be built with only a single exit stair. This is noteworthy because, here in Canada, if you were to try and build an equivalent 6-storey building on an equivalent 100 square meter site, you would be required to have two exit stairs. And that would create more non-leasable space and make it even more challenging to develop such a small building.

It is for this reason that single-stair buildings have been getting an increasing amount of attention as of late. They are seen as a way of encouraging more missing middle housing.

So where are single-stair buildings currently allowed? Below is a map from Seattle-based Larch Lab showing the maximum number of storeys for point access blocks (what they call single-stair buildings) around the world. Based on this, Canada is one of the most conservative countries on the planet when it comes to required exiting (I don't want to speak for any of the grayed-out countries). It also shows that much of the world allows 6 or more storeys.

Larch Lab is a major advocate for point access blocks and they have this policy brief outlining the problem and the opportunities. One of their most interesting statistics has to do with minimum project size inflation. As recent as 2000, only about 13% of all multifamily completions in the US had more than 50 units. Today, this number has jumped to more than 55% of all new multifamily buildings, meaning we are quickly losing our ability to build small and intimate.

Point access blocks can help with this.

Of course, the reason we have exiting requirements in our building codes is because of life safety. But there's research to suggest that this level of redundancy may not be needed in certain buildings. According to the above policy brief, the average death rate (caused by a building) in point access block countries like Switzerland, France, Italy and Germany, is significantly lower than that of the US. On top of this, almost no countries in the EU require buildings less than 28m tall to be sprinklered. The US does.

All of this said, I don't think that single-stair buildings are a silver bullet for missing middle housing. It is just one important ingredient in a complicated recipe. And as evidence of this, we can look to Seattle. The 2018 Seattle Building Code allows point access blocks up to 6 storeys, which is a rare occurrence in the US. However, the city appears to be still working on missing middle reform. Presumably other ingredients are still -- missing.

Image: Larch Lab