How single-exit stairway apartments change layouts, costs and community
Cities from Vancouver to Toronto are changing rules to allow single-exit stairway apartment buildings. The design can cut costs, improve daylight and still meet modern fire-safety standards.
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By Torontoer Staff
Several Canadian jurisdictions have begun permitting single-exit stairway apartment buildings, a form long common in Europe and Australia but restricted in North America. Architects and planners say the design can deliver larger, brighter units and add gentle density, while meeting contemporary safety standards.
Early approvals in Vancouver and Toronto, and guidance from Edmonton, suggest the model may spread. Developers and code consultants argue that modern sprinklers, ventilation and fire-retardant assemblies can provide an equal or better safety outcome than the traditional corridor-plus-two-stairwell layout.
What a single-exit stairway building looks like
Unlike the North American norm of a central corridor with stairwells at each end, single-exit designs concentrate vertical circulation in one shared stair. Apartments are arranged to get windows on two or more sides, improving cross-ventilation and daylight. Variations include scissor stairs, which intertwine stair flights to serve apartments on alternate levels while keeping openings compact.
Why architects and advocates favour the approach
- More usable floor area, since long internal corridors are reduced or eliminated
- Bigger, family-friendly units with windows on multiple sides
- Lower construction costs, typically 6 to 13 per cent less in some studies
- Potential for gentler densification in low-rise neighbourhoods, addressing the so-called missing middle
- Shared stairways that can strengthen neighbourliness compared with long, anonymous corridors
Architects also point to aesthetics and urban fit. On small lots, single-exit buildings can produce more interesting apartment plans and a finer grain of housing than large, repetitive blocks.
Safety, technology and the building code
The key to wider acceptance is integrating contemporary fire-safety measures. Common elements in approved projects include automatic sprinklers throughout, fire-retardant floors and walls exceeding minimum durations, wider stair landings to allow simultaneous passing of firefighters and evacuees, and mechanical systems that pressurize stairs to keep smoke out.
Some architects have added exhaust fans that activate with fire alarms to clear smoke from stairwells. Research, including a Pew Charitable Trust analysis, finds that four- to six-storey single-exit buildings with sprinklers have a strong safety record when compared with conventional apartment buildings and single-family homes.
This is the missing link to the missing middle.
Inge Roecker, architect and UBC professor
How approvals are happening in Canada
Cities are using alternative solution proposals to assess single-exit designs on a project-by-project basis. In Vancouver, council recently amended the local code to allow these apartments more clearly. Edmonton has provided guidance for alternative solutions, and Toronto has issued at least one postwar approval after detailed negotiation.
Those approvals often require prolonged review and, in some cases, political involvement. A Toronto developer and planner secured a permit only after they persuaded municipal officials that their design would exceed the safety performance of code minima, and after intervention at the mayoral level.
This was the first single exit stair project with an alternative solution proposal that has come to our attention. Our goal was to help find a way to make it work and set an example that this kind of building is feasible.
Shirven Rezvany, spokesperson for Mayor Olivia Chow
Officials at the national level are also adapting model codes, and jurisdictions in the United States, including Seattle and New York, plus the state of Hawaii, now permit new single-exit buildings under specified conditions.
Practical considerations for residents and buyers
- Confirm the building has a full sprinkler system and documented evacuation procedures
- Ask about stair pressurization and backup power for mechanical ventilation
- Review insurance implications and whether the building uses enhanced fire-rated materials
- Consider unit layouts on lower-rise sites: expect more daylight, cross-ventilation and family-sized plans
- Assess how the shared stair is designed for daily use and informal social interaction
Where this could lead
Code change tends to follow demonstration. The example of taller engineered-wood buildings shows how early approvals can shift expectations and open the door for broader regulatory updates. Building-code consultants predict a similar arc for single-exit stairway apartments as more projects prove safe and deliver livable units at lower cost.
Then we went to six, and everyone’s like, ‘Oh, nothing happened to these six-storey buildings. They were totally fine.’ And next thing we’re allowed 12s, and now we’re allowed 18s.
Jack Keays, building code consultant
If municipalities continue to refine approval pathways and require robust safety measures, single-exit stairway buildings could expand housing options in established neighbourhoods while offering better apartment designs and lower construction costs.
Early projects will matter. They will shape how officials judge trade-offs between layout, livability and safety. For buyers and renters looking for low-rise family housing with thoughtful design, the new wave of single-exit buildings is worth watching.
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