CMHC Housing Supply Challenge
Round 4: Building for the Future

Single Stair Alternative Solutions

Design Innovation for Middle Housing


Prescriptive building codes across Canada require two means of egress for any multi-unit residential building exceeding two storeys. However, a review of codes across other jurisdictions shows that multiplexes and small apartment buildings can be safely constructed with a single exit stair. This approach supports gentle density, maximizing land use on small sites while improving sustainability, accessibility and design flexibility.

Single exit stair (SES) building design adds enough floor area for at least another bedroom on each storey of a building and improves the feasibility of infill housing on small properties. The solution also allows for apartment layouts with more natural light and fresh air, as well as making it easier to provide an elevator to make three-storey buildings fully accessible.

The Canadian Urban Institute hosted a series of “Single Stair Sessions” to bring together leading architects, engineers and building code experts to explore how alternative building code compliance can expand housing options in urban areas:

March 18: Single Stair Sessions, Day 1 – Pilot Projects and Prototypes

March 19: Single Stair Sessions, Day 2 – Safety And Sustainability

March 20: CityTalk - Addressing Canada’s Housing Supply: Can Regulations Drive Housing Innovation?

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