Older central Montreal neighborhoods, developed in the early 20th century, are among Canada’s densest urban areas. This is achieved through the iconic Montreal “plex” design, stacking two or three apartments on narrow lots without sacrificing livability or relying on high-rise buildings.

Key insights:

The older neighbourhoods in central Montreal – developed in the first half of the 20th century – comprise some of the densest urban areas in Canada, something that is achieved without sacrificing livability or frequent recourse to high-rise buildings.

As this Small Housing Case Study outlines, the key to this puzzling success is the iconic Montreal “plex”, i.e., the stacking of two (“duplex”) or three (“triplex”) apartments on narrow (20-25 feet) lots with each apartment having its own front and back door and civic address.

This convivial solution that nicely combines density, livability, affordability, and conservation, iconic to Montreal, flourished in the first half of the 20th century but then fell victim to changing building regulations in the post-war period. A demand for this traditional housing solution eventually led to a relaxation of building regulations and return of the plex as an acceptable housing solution.