Canada needs more housing. One of the Items frequently cited in preventing housing from being built is a building code requirement that multi unit buildings over 2 stories have 2 sets of egress stairs. Urbanists claim this is an unnecessary requirement. The IAFF says single egress stairs (SES) “Put simply, lives will be endangered.” As an architectural historian, and a firefighter, I think I’m uniquely qualified to weigh in on this topic.
Please note that the thoughts and opinions here are my own, and do not reflect positions of anyone else, unless otherwise noted.
The General Argument for allowing single stair buildings generally covers these points:
- Single stair buildings reduce construction costs
- They allow for more ideal unit layouts, suitable for smaller lots
- they are common in Europe
- Seattle and NYC allow them
- Fire safety can be achieved with mandatory sprinklers and pressurized stairwells.

The argument is that the 2 egress stair requirement prevents the construction of missing middle housing. Missing middle housing refers to a range of medium density housing types, like duplexes, townhomes, and small apartment buildings, that fit within existing single-family neighbourhoods. The dual egress stair requirement specifically effects stacked townhouses and small apartment buildings, where a multi-unit building with a single stair could be built in a standard single family home lot; The use of a single stair enables larger units to be built with better layouts. Missing middle structures are typically 3 stories, with midrise being in the 4-6 story range.

The 2 stair requirement typically results in a built form with a double loaded hallway. that is there are units on both sides of the hall, and with the exception of the corner units, only offers windows on one end. this can lead to units that lack natural light, and poor natural ventilation. They result in larger buildings, which would not fit on single lot.

How we got here
In April 2022, Conrad Speckert of LGA Architectural Partners (based in Toronto, and maintainers of the Singlestair.ca and https://secondegress.ca/ sites) and David Hine of David Hine Engineering Inc. submitted the code change requests to the Canadian Commission on Building and Fire Codes to modify Part 3 – Single Egress for Multi-unit Residential Buildings up to 6 Storeys and Part 9 – Single egress for Multi-unit Residential Buildings up to 3 Storeys. the Canadian Commission on Building and Fire Codes was established by the National Research Council to produce model building codes. Anyone can submit a proposed code change via a webform, The commission then evaluates the proposed changes for possible inclusion. It should be noted that this is the accepted and appropriate path for a code change to initiated.
In Nova Scotia, the Building Code Act regulations adopt the National Building Code of Canada 2020 with a errata and changes made prior to April 1 2023. Changes to that code can be made my the province, through regulations.
BC rapidly instituted a code change through regulation that took effect in August 2024 permitting single exit stair apartment buildings up to six stories as long as the following are met: occupancy load per floor limited to 24, travel distance to exit is limited, smoke management is included, sprinkler systems are installed, and increased fire inspections. The BC changes certainly sparked debate in Canada. The position of the Canadian Association of Fire Chiefs is that any changes to the NBC should go through the normal code adoption process, and that process should not be circumvented via alternate means to enable SES buildings. BC implemented the change very quickly, and both the BC Fire Chiefs, and firefighters association were concerned about safety. the Greater Vancouver fire chiefs indicated that they would be pressed to meet the response standards of NFPA 1710 to a six story SES building, among other concerns.
In a 2026 report to Halifax Council, it was pointed out that single stair buildings could be built now with approval of building officials through the NBC’s alternative compliance method, which allows builders to meet the goals of the building code through other methods. Approved single stair buildings in other provinces have been enabled this way, typically by shorting exit distances, including sprinklers where they would otherwise not be required, and increasing fire separation standards, beyond what would normally be required for a building that size. Several provinces have single stair buildings in excess of the NBC 2 floor height as a result of the alternative compliance mechanism in the NBC. Some examples of approved projects can be found at https://singlestair.ca/Pilot-Projects. Project pages there show plans and how alternative compliance was achieved.
The downside to alternative compliance is that it becomes regulatory red tape. there is not a rule, and the design becomes a negotiation with building officials. It enables missing middle housing, but not rapidly. This is why a change to the building code is the preferred solution.
The Seattle Special
The City of Seattle introduced what has become known as the Seattle special, a six story SES building in 1978. The goal was to encourage multi unit infill on smaller lots. It has been very successful, and the same rules were adopted by Honolulu in 2012. While the Seattle special is a compelling success story, isn’t even recommend to other cities by Seattle. The chief fire prevention officer, fire marshal, and building department have all spoken caution about the style being exported to other cities, and maintain that the only reason for their success with that style is because of their well funded fire service. The Seattle Fire department has ~900 operations members, in 33 stations, serving a population of 755,000. the department has a Budget (2025) of $327million USD
Firefighting and Life Safety Impacts
To understand why single egress stairs in large buildings are a bad idea, we need to understand how fire response occurs, as well as how a fire spreads.
When a fire starts, at some point the fire is detected, and someone is notified. from there the fire department is alerted, dispatched, and travel to the scene. In best case scenarios, this can take 5-6 minutes for the first due unit to arrive. The NFPA 1710 standard specifies the ideal response time and number of firefighters required to deal with an incident. Many departments fall short of this standard. With the increased use of synthetics in our houses, Fires can grow rapidly and explosively in minutes.
In the above video, the synthetic fire room flashed over in less time then the typical response time for a first arriving unit. Once that unit arrives, additional time is needed to reach the unit, setup equipment and begin to fight the fire.
The best data suggests that ~12% of fires occur in multi-residential buildings. This amounts to about 2400 fires per year across the country. 96% of these fires resulted in injury or death to occupants. In just over half of unintentional residential fire deaths (~179/year), the individual was age 70 and up. In 14% of unintentional residential fire deaths, there were mobility-related issues or cognitive impairments. these were people who needed to be found promptly and rescued by the fire department.
Modern multi-unit buildings are designed to contain a fire to a unit. This is why unit and stairwell doors have auto-closers on them, However there is no guarantee that these will work. People prop open doors, and auto-closers fail, or get disabled because they can be inconvenient. If a fire starts in a unit, and the door is left open, The hallway fills with smoke. If their is open access to stairwell, the stair becomes a chimney, rendering it impossible to use for residents above the fire floor. This also complicates firefighting efforts, as crews now need to climb a stairwell in an IDLH (Immediately dangerous to life and health) environment before they even get to the fire floor.
Firefighters stage in stairwells – they get clogged with hose and other equipment. this means it becomes harder for residents to egress.
A benefit cited by single stair proponents is improved ventilation in units. Given the above situation combined with increased airflow can lead to a wind driven fire. This turns a normal fire into a blast furnace, with much more rapid fire spread, and much higher heat, into the hallway and stairwell. To be clear, I’m not suggesting that we should have poorly ventilated apartments for fire safety, but pointing out how the bad situation above can be made worse.
SES proponents argue these concerns can be addressed with sprinklers and pressurized stairwells. Both of these rely on mechanical systems, and both can fail. Pressurizing stairwells requires fans, and sprinklers rely on fire pumps, both those rely on electricity, the supply of which cannot be guaranteed in a fire. There have been numerous examples where sprinklers have failed to control a fire, or even activate when needed. problems with smoke alarms were reported in almost 9% of fires, while in 7.3%, automatic extinguishing equipment did not work because the fire was too small or other reasons. The 2022 Winters Hotel fire in Vancouver, B.C., where two people perished in a building equipped with a sprinkler and fire alarm system, shows that fire protection systems are not the sole enablers of safety
reliance on mechanical solutions required stepped up inspection regimes from cities.
A single stairwell constitutes a single point of failure. If that stairwell becomes unavailable, the workload for firefighters increases – they must find alternate means to access the fire, as well as alternate means to evacuate residents. Research of Canadian apartment building fires showed 9% originated in the means of egress hallways and stairwells and that smoke affected primary access routes in more than 42% of the fires. SES Proponents typically down play the risk, citing examples from buildings that exist, which have multiple sets of stairs.
Prompt response from the fire department, with sufficient aerial apparatus on scene is really the only way to mitigate risks from a single egress point. This means cites need to increase staffing and buy more equipment. But even this might not be enough, as the lots best suited for missing middle densification are also the most access constrained, in many cases only one side of the building can be properly accessed.

Canadians tend to build with wood. The NBC currently allows Lightweight timber frame construction up to 6 stories. There are many examples of these buildings in Halifax. Lightweight construction can burn. The Hanwell Drive fire in Middle Sackville is a good example. The fire separations enabled everyone to get out, however the sprinklered building lost much of its roof and top floor in the fire. This building has 2 stairwells, one of them remains intact.
Constructing SES buildings out of non combustible construction could be one way to reduce the risk. NYC allows SES buildings of up to 6 stories. Each story is limited to 2000sqft, and the building must be of non combustible concrete or steel construction. The structure of concrete buildings wont burn, which greatly reduces the risk of structural failure in fire. The downside is that it requires specialized skill to construct and is more expensive, negating some of the benefits of SES construction. Many other jurisdictions which allow much larger SES buildings primarily build with non-combustible construction.
The Grenfell tower fire in London, England was certainly made worse by the existence of only one stairwell. it became clogged with firefighting equipment, and also became a chimney. Grenfell tower was a 24 story building of non-combustible construction, though it lacked sprinklers, adaquite fire alarms, and was wrapped in a flammable foam cladding. That fire serves as a reminder that safety is achieved through multiple complementary approaches, and simply doing away with a requirement for a second egress stair is not a viable solution.
Micro Mobility
A recent trend in residential fires is with micromobility devices – e-bikes and e-scooters. Their use has them typically stored in the entry areas of buildings and units. When a Lithium ion battery fails, it releases toxic gasses and jets of flame. There have been several fire deaths reported in various cities when a mobility device caught fire and impeded escape. There have been mobility device fires in units in Halifax. A single egress point compromised by a mobility device can be a serious danger and hazard to residents.
Conclusions
There probably is room to relax the Canadian national building codes 2 story rule. The International building code, used in much of the US allows for single egress stairs in building up to 3 stories, with 4 units per floor. Even the IAFF and IAFC, who strongly oppose increasing the permitted building height state that it unsafe in buildings over 3 stories. The National Fire Protection Association Life safety code, NFPA 101, allows for 4 stories. Both codes require alternate measures, including limited length of exits, and inclusion of sprinklers.
Given the positions of the IAFF, IAFC, and NFPA, changing the NBC to allow 3 stories SES should be fairly uncontroversial. Adoption of the 4 story NFPA guidance should be considered more carefully
The NFPA publishes consensus standards. they form committees made up of experts on all sides, and the stuff they all agree upon makes it into the standard. Its not a perfect system, but its a credible process that generates sound recommendations. In the Fall of 2024, the NFPA held a SES Symposium, which resulted in a report, attached below.
Code changes for larger buildings should go through the normal code adoption process, to ensure the science behind it is sound. The leap from 3/4 stories to adoption of the Seattle Special requires more consideration, and larger investment in the fire department. Once buildings get above 6 stories, you are no longer dealing with missing middle housing, and the justifications for SES become suspect, and were beyond the scope of the 2022 Code Change request.
Notes
- CAFC page on Single Egress stairs https://cafc.ca/page/single-egress
- IAFC Position Statement: https://www.iafc.org/about-iafc/positions/position/reducing-stairs-in-residential-buildings-higher-than-three-stories
- IAFF Position: https://www.iaff.org/wp-content/uploads/2025/03/2025-Single-Exit-Position-Stmt-FINAL-1.pdf
This report was produced by Len Garis, retired Surrey BC Fire Chief , and professor with the University of the Fraser Valley to look at what data can tell us. it is the source for many of the statistics in this post.







































































