Small Housing Case Study: Exemptions in Building Code on construction & conversion of buildings

Montreal’s Iconic Plex: How Building Code Exemptions Revived a Classic Housing Model
In Montreal’s older central neighbourhoods, narrow-lot “plex” buildings — duplexes and triplexes stacked vertically, each with its own front and back door — created some of Canada’s densest, most livable urban areas without relying on high-rises.

This case study explores how post-war building regulations nearly erased this housing type, and how public demand led to key building code exemptions that brought the plex back. It’s a story of density, affordability, and conservation working in harmony.

Discover how smart code flexibility can reintroduce housing forms that meet today’s gentle density needs.

Keywords: Montreal plex; duplex housing; triplex housing; gentle density housing; building code exemptions; small-scale multi-unit housing; affordable housing Montreal; urban density solutions; missing middle housing Canada; heritage housing models