Subscribe
It's fun to examine projects that I could never underwrite or build in Toronto. Here's another one from Tokyo — a 10-storey, single-stair apartment building on a busy street, next to a metro station.
The site itself is only 59.49 m2 (~640 ft2), and the building footprint is 47.97 m2 (~516 sf), for a total of 388.28 m2 (~4,179 ft2). There's retail on the first and second floors, one home per floor on levels 3 through 8, and then a two-storey home on levels 9 and 10. All of this is serviced by a single elevator, and a single open-air egress stair off the back.
The building itself uses a simple structural system involving 6 columns (which you can see evenly placed on the plans). According to the architect's notes, they started with a simple 4-column design, but apparently the columns were too large and compromised the suite layouts.
Tokyo is a unique city and this kind of housing wouldn't work everywhere. But there's a universal lesson here: removing barriers and allowing small infill projects is a good thing for cities. Until these projects are feasible, we won't know exactly what the market actually wants and could support.
Photos from Hiroyuki Ito Architects
As many of you know, the Ontario Building Code requires multi-residential buildings over two storeys in height above grade to have more than one means of exiting the building. This typically means two exit stairs.
If you'd like to build something more ambitious than this, you generally have two options. One, you could design your second-floor homes to be multi-storey. I'm not a building code expert, but I've seen architects like Craig Race (and others) do this without triggering the requirement for a second exit.
Your second option is to apply for what's called an "alternative solution." This is basically a way of saying to the building department, "Hey, my design deviates from the standard prescriptive method, but it still achieves an equal or greater level of safety, performance, and functionality, so you should approve it anyway."
Last year, the City of Toronto sent a message that it was going to be more open to single-egress alternative solutions. It commissioned a report that looked at the feasibility of relaxing egress requirements for buildings up to four storeys and published a guide to help builders prepare these proposals. The goal was and is to encourage more missing middle housing.
So has it worked?
This past week, Pamela Blais shared her experiences on Twitter. She is trying to build a three-storey sixplex (Part 9 of the Ontario Building Code) with a single stair, so she submitted an ASP. It included:
Fully sprinklered building
Widened exit stair (1200mm vs. 900mm)
Expanded landings (1650mm)
Stairwell skylight for smoke exhaust
Improved fire ratings (structure, suite separation, exits, and balconies)
Balcony in every home for refuge or direct exit
And the city's response was: "Nope. This does not meet the required performance levels."
I can also share that we have had meetings with code consultants regarding the feasibility of doing a single stair in a six-storey building and the guidance we received was that there's no way an ASP would be approved. We would be wasting our time and money. All of this should make it clear that we're not there yet.
Thank you, Pamela, for sharing your experience. As one commenter on Twitter said: "A noble quest you are on."
One of the trademarks of Tokyo's urban landscape is a lot of exterior exit stairs. For example, our hotel is almost 20 storeys and it has two exit stairs, both of which sit outside of the building. Here's a photo taken from the corridor. You can also see other buildings in the background with similar exit stair configurations.
It's fun to examine projects that I could never underwrite or build in Toronto. Here's another one from Tokyo — a 10-storey, single-stair apartment building on a busy street, next to a metro station.
The site itself is only 59.49 m2 (~640 ft2), and the building footprint is 47.97 m2 (~516 sf), for a total of 388.28 m2 (~4,179 ft2). There's retail on the first and second floors, one home per floor on levels 3 through 8, and then a two-storey home on levels 9 and 10. All of this is serviced by a single elevator, and a single open-air egress stair off the back.
The building itself uses a simple structural system involving 6 columns (which you can see evenly placed on the plans). According to the architect's notes, they started with a simple 4-column design, but apparently the columns were too large and compromised the suite layouts.
Tokyo is a unique city and this kind of housing wouldn't work everywhere. But there's a universal lesson here: removing barriers and allowing small infill projects is a good thing for cities. Until these projects are feasible, we won't know exactly what the market actually wants and could support.
Photos from Hiroyuki Ito Architects
As many of you know, the Ontario Building Code requires multi-residential buildings over two storeys in height above grade to have more than one means of exiting the building. This typically means two exit stairs.
If you'd like to build something more ambitious than this, you generally have two options. One, you could design your second-floor homes to be multi-storey. I'm not a building code expert, but I've seen architects like Craig Race (and others) do this without triggering the requirement for a second exit.
Your second option is to apply for what's called an "alternative solution." This is basically a way of saying to the building department, "Hey, my design deviates from the standard prescriptive method, but it still achieves an equal or greater level of safety, performance, and functionality, so you should approve it anyway."
Last year, the City of Toronto sent a message that it was going to be more open to single-egress alternative solutions. It commissioned a report that looked at the feasibility of relaxing egress requirements for buildings up to four storeys and published a guide to help builders prepare these proposals. The goal was and is to encourage more missing middle housing.
So has it worked?
This past week, Pamela Blais shared her experiences on Twitter. She is trying to build a three-storey sixplex (Part 9 of the Ontario Building Code) with a single stair, so she submitted an ASP. It included:
Fully sprinklered building
Widened exit stair (1200mm vs. 900mm)
Expanded landings (1650mm)
Stairwell skylight for smoke exhaust
Improved fire ratings (structure, suite separation, exits, and balconies)
Balcony in every home for refuge or direct exit
And the city's response was: "Nope. This does not meet the required performance levels."
I can also share that we have had meetings with code consultants regarding the feasibility of doing a single stair in a six-storey building and the guidance we received was that there's no way an ASP would be approved. We would be wasting our time and money. All of this should make it clear that we're not there yet.
Thank you, Pamela, for sharing your experience. As one commenter on Twitter said: "A noble quest you are on."
One of the trademarks of Tokyo's urban landscape is a lot of exterior exit stairs. For example, our hotel is almost 20 storeys and it has two exit stairs, both of which sit outside of the building. Here's a photo taken from the corridor. You can also see other buildings in the background with similar exit stair configurations.
Oftentimes these stairs will also be positioned on a building's primary elevation, making them form part of the overall architectural expression. There's no shame in doing that here. This is curious to me because it means that, on tight urban sites, you're giving up part of your frontage to egress. The alternative would be to burry it in the middle of the building and have it transfer over at some point.
In any event, my first thought when I see a lot of exterior circulation is usually that the place must have a mild climate. And indeed, this is true of Tokyo. The average January and February lows and highs are 10 degrees and 5 degrees, respectively. Snow is extremely rare here. But that doesn't seem to be what's driving this egress approach.
Because if you go up north to Sapporo, where they get upwards of 500cm of snow each year, it too has exterior exit stairs. Closer to home, there's also the example of Montreal, which is similarly known for its exterior stairs (both in its older housing stock and in some of its newer housing stock). So it can't just be a weather thing.
The more likely hypothesis is that it's simply cheaper and easier to build this way. There may also be local regulations that either directly or indirectly encourage it, beyond it just being more cost effective. Interestingly enough, though, exterior stairs don't seem to be as common in newer buildings (but this is just my anecdotal observation from the last few days).
We talk a lot these days about single-stair buildings. And I think it's clear that we need to start allowing this for larger infill projects. But Tokyo also has me wondering if we should be having a parallel conversation about more open-air exit stairs and corridors. Climate is clearly no excuse. If it can help bring down the cost of building, then it's something to consider.
Oftentimes these stairs will also be positioned on a building's primary elevation, making them form part of the overall architectural expression. There's no shame in doing that here. This is curious to me because it means that, on tight urban sites, you're giving up part of your frontage to egress. The alternative would be to burry it in the middle of the building and have it transfer over at some point.
In any event, my first thought when I see a lot of exterior circulation is usually that the place must have a mild climate. And indeed, this is true of Tokyo. The average January and February lows and highs are 10 degrees and 5 degrees, respectively. Snow is extremely rare here. But that doesn't seem to be what's driving this egress approach.
Because if you go up north to Sapporo, where they get upwards of 500cm of snow each year, it too has exterior exit stairs. Closer to home, there's also the example of Montreal, which is similarly known for its exterior stairs (both in its older housing stock and in some of its newer housing stock). So it can't just be a weather thing.
The more likely hypothesis is that it's simply cheaper and easier to build this way. There may also be local regulations that either directly or indirectly encourage it, beyond it just being more cost effective. Interestingly enough, though, exterior stairs don't seem to be as common in newer buildings (but this is just my anecdotal observation from the last few days).
We talk a lot these days about single-stair buildings. And I think it's clear that we need to start allowing this for larger infill projects. But Tokyo also has me wondering if we should be having a parallel conversation about more open-air exit stairs and corridors. Climate is clearly no excuse. If it can help bring down the cost of building, then it's something to consider.
Share Dialog
Share Dialog
Share Dialog
Share Dialog
Share Dialog
Share Dialog
