A truly ridiculous floor plan, the result of Chicago not allowing single exit stair design and not allowing scissor stairs (interlocking separate enclosures).

Stockholm’s pedestrian fatality rate per 100k is 0.45. The U.S. is over 5x that. Like much of the EU Stockholm uses standards of 9.8’ for city street lanes and allows for 10.8’ in bus and truck corridors. The U.S. sets a 26’ minimum width for streets and common lane widths are 12-14’.

Three different kinds of illegal stepping out of our Stockholm apartment.

After the Grenfell fire, England changed its building codes to cap single-stair buildings at just 18 meters (or ~60 ft) high. Their own regulatory cost analysis found that if they capped it at 30m instead, it would achieve 90% of the benefits while cutting the overall societal cost by almost half.

E24-24, my proposal to raise the IBC’s single-stair apartment building height limit from three stories to four, has passed the final membership vote, and will now officially make it into the 2027 IBC 🎉

New page on switchgear (electrical infrastructure for larger buildings) just dropped. it is a great explainer on what the hardware is and what to expect. app.bchydro.com/accounts-bil...

In Canadian Architect, I write out 10 case studies of housing innovation in Canada, from single-stair multiplexes to Indigenous-led city-building and rapid-assembly panelization. www.canadianarchitect.com/housing-in-a...

The Council just passed legislation to allow single-stair and single-entrance apartment buildings up to six stories in DC. Allowing single-stair buildings: ✅ Reduces housing construction costs ✅ Enables housing on narrow city lots ✅ Facilitates more family-sized units The bill passed unanimously.

"The kinds of multifamily we build most of, where many homes share a common internal corridor, is actually vastly more dangerous than single-stair buildings which are smaller and have fewer residents per corridor or stair." commonwealthbeacon.org/opinion/the-...

Single-stair gets the New York Times treatment. @holz-bau.bsky.social reminds us why they call the last line the kicker: www.nytimes.com/2026/03/04/b... (gift link)

In the second issue of EXPO, I look at the history of the condominium in Canada. Why did condos become the primary mode of delivering multi-unit urban housing? Why did we build so many? And what happens now that nobody's buying?

'Fully embracing the single-stair model would improve life in Toronto & beyond by enabling the design of buildings w/ abundant natural light, cross-ventilation, & more generous layouts, and by also supporting the formation of stronger, intergenerational social bonds' www.kpmb.com/insight/how-...

Doug Ford said it had to close because the roof was unstable. Massive snow dump, roof just fine. Doug Ford lies.

Interesting floor plan that shows what mitigations are possible that are not a second stair or sprinklers (neither of which are common in new apartment buildings in France). The lower floors have a short double-loaded corridor with five units of up to 4BR, which I... divisare.com/projects/548...

Updated to include changes in City of Vancouver, recent change from 16 to 20 storeys in Sweden, and permissions for existing buildings in Nova Scotia. secondegress.ca/Jurisdictions

Fascinating 2008 paper on "Redefining fire safety in Swedish high-rise buildings" speaks to risk-informed design of single exit stair high-rise buildings in Sweden, featuring the Turning Torso (54 storeys, residential/offices) and the Kista Science Tower (31 storeys, offices) wuz.se/wp-content/p...

A new bombshell modeling report by the State of Minnesota has found that small single-stair buildings with smoke-separated stairwells are likely to be SIGNIFICANTLY SAFER than typical double-loaded apartment buildings

Today, the City of Vancouver approved the code change to the Vancouver Building By-Law (VBBL) to allow Single Exterior Exit Stair (SEES?!?) for up to 6 storeys in height, as well as accommodating scissor stair layouts for 6 storeys of limited area by reducing the minimum distance between exits.

Excited to share a new video I produced with Urbanarium on their Decoding Timber Towers competition, which challenged teams to design 8–20+ storey buildings out of wood! Check it out here: www.youtube.com/watch?v=gQ42...

The Mid-rise Pattern Designs endorsed by the Government Architect of New South Wales (Australia) provides a catalogue of small lot and corner lot apartment building designs of 4 to 7 storeys in height. Take a look at the floor plans and renderings. www.planning.nsw.gov.au/government-a...

Somebody in the audience pointed out something that I didn’t know, which is that Queensbridge Houses, the largest NYCHA project in the city (and thereby largest public housing complex in North America), is single-stair. platform-affordable-dwelling.bk.tudelft.nl/database/201...

"Although corner stores may seem a trivial issue, allowing them near where people live can make a neighbourhood more pleasant and, well, convenient. But antiquated zoning laws make them illegal in most neighbourhoods of Canada..." www.theglobeandmail.com/opinion/edit...

“The era of shoebox condos is over” in the Globe and Mail today - a feature on single stair: ”Yet with features such as sprinklers, smoke-sealed doors and more reliable fire alarm systems, mid-size apartment buildings can be just as safe...” www.theglobeandmail.com/investing/pe...

Fascinating article. This really stood out to me: smaller cars are more popular in Canada than in the U.S., but due to Transport Canada tying its safety standards to the U.S., Canada gets stuck with our huge cars instead of smaller European models. I wonder if the same is true of U.S. cities 🤔

I’m at the launch of Oregon’s design competition for sunlight suite buildings - neighborhood-scale mulifamily buildings designed around one central staircase. “This is one of those innovations whose time has come,” says Gil Kelley of @1000oregon.bsky.social.

Single-stair buildings up to 6 stories are legal in Baltimore City! Headed to Mayor Scott's desk for signature.

This pilot project for SES building design is also featured here. Others of similar configuration have been accepted in Vancouver, Edmonton and Hamilton. singlestair.ca/Office-Ou

Winner of Billings Architectural Association's 2025 Single-Stair Housing Competition by Trae Schwenneker. The competition focused on urban infill in Downtown Billings, MT. The winning project honors the historic brick architect of Montana Avenue w/ ground-floor retail & four upper levels of condos.

Our team placed 2nd in the Urbanarium "Decoding Timber Towers" architectural ideas competition (1st place to @moriyamateshima.bsky.social) with our 20-storey mass timber tower featuring a compact elevator and exit stair core, exposed ceilings, prefab balconies and a balanced mix of 1 to 4 bed homes!

Pew finds something that everybody in codes and standards knows but few will say out loud: we apply far stricter fire safety standards to apartments than to houses. www.pew.org/en/research-...

“Modern apartments have a fire death rate … six times lower than older apartments… (or) single-family homes…” Aka why new single stair flats would be among the safest buildings in your city. www.linkedin.com/pulse/why-bu...

Modular, mass timber, and single-stair This workforce housing project in Montana maxes out the current IBC code limitations on single housing with a 10,000 sf floor plate and 8-bed units that each feature shared living, kitchen, and laundry. www.idcubedmodular.com/blank

This comparison shows the price of putting an internal garage on a rowhouse Both of these rowhomes are ~16' wide Left: 2BR+Den/3BA Right: 4BR/3.5BA So the cost is losing TWO bedroom.

Visited two of my favourite Point Access Blocks (single stair apartment buildings) in Berlin… E3 on Esmarchstrasse in Prenzlauerberg (encapsulated mass timber, noncombustible exterior stair) and Walden 48 co-op housing project nearby in exposed mass timber and treated wood cladding.

Why are single-stair buildings actually SAFER than two stair buildings in some circumstances? It seems counter intuitive… obviously, more redundancy is better, right?

Important TOMORROW: The LA City Council is going to vote on whether to legalize single stair buildings. Opponents have launched a disinformation campaign, and we need people to give public comment in support. Will you be joining me tomorrow at 10am in City Hall?

Design study comparing single-stair vs multiple stair egress on a small 5,500 SF lot in Denver: (L) double-loaded corridor •71% efficiency •(4) units (R) single-stair •87% efficiency •(4) dual-aspect units

Week 2 On a tiny corner lot in Boston, Condor Street Housing shows how much a single stair can do. A small elevator makes every unit barrier-free, linked by a short corridor to meet code. Even on one of the tightest sites, the plan delivers safe and accessible homes.

Behold the power of single stair

My first Starter Pack! The Canadian urbanism and planning community on here is growing. Give these folks a follow. Some well known faces … and some you should get to know! (please re-post!) go.bsky.app/AEYL7FZ

I had a good conversation with Joe Kelly on his Mass Construction Show podcast about single-stair. It’s for construction/code/fire folks, so it was more technical than most.

A new state has joined the single-stair club: New Hampshire now allows four stories of multifamily, four units per floor, with a single stair. And it’s the cleanest code section there is – same conditions as for three stories. www.centerforbuilding.org/trackers?tra...

LA's City Planning department thinks single stairs would be great for Los Angeles:

Greater Toronto got its Greenbelt in 2005. It took 20 years for the City of Toronto to partially legalize sixplexes. I think, if you want a greenbelt, you need to legalize substantial density *first*. Not just sixplexes. Single-stair mid-rises everywhere (high-rises around all subway stations).

Yesterday, Laurence Holland and Kevin Bridgman of KPMB Architects wrote an article on the principles of the Downsview Urban Design Guidelines... They note: "If Canadian building codes are reformed to permit single-stair egress up to six floors,..." (see thread) www.kpmb.com/insight/the-...

"Canada must remove barriers with the European Union to more deeply integrate Canada's economy with the EU in order to reduce our dependence on the US" 🟢 Agree: 85% 🔴 Disagree: 12% open.substack.com/pub/canadian...

Would someone like to guess what all these Spanish apartment buildings have in common that makes them illegal to build in most of North America?

Single stair Swiss high rise. 23 floors of apartments. 1, 2, 3, 4, and 5 (!!!) bedroom homes. Large, functional balconies. Solar protection. This proposal didn't even win the competition. I don't love all of the concrete, but imagine this building made of timber. afasiaarchzine.com/2025/07/rank...

Many North American cities spend more on transit expansion than cities in Europe and Asia, but get very little transit built because they are not efficient at building transit. Toronto, LA, Seattle, NY are probably the worst offenders.