Small Housing Case Study: Single Egress Stairs

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Key insights:

By prohibiting single egress designs at scale, the National Building Code limits the feasibility of “missing middle” buildings. The two-egress requirement made sense when the NBC was first developed in the 1940s when wood frame buildings were highly combustible and fire safety features were primitive.

Today, modern firefighting practices, advanced fire alarms, automated sprinklers, fire resistant separations (walls, doors, ceilings) and other innovations have rendered the two-egress model obsolete in low-rise settings. It is now technically possible to create multi-unit wood frame buildings with a single egress that are as – or even more – fire safe than a two egress building of yesteryear.

This case study explores an emerging movement across Canada to change the NBC to allow for single-egress residential buildings. At the forefront of the movement is LGA Architectural Partners and David Hine Engineering, who have submitted an application to the Canadian Commission on Building and Fire Codes to amend the NBC so as to allow single-egress buildings of up to six storeys above grade.