Anyone who has visited or lived in Montreal has seen an impressive variety of external staircases that decorate the homes of the Canadian city’s historic neighborhoods. Beyond the range of architectural styles that adorn the facades and interiors of this local type, the Plex is mostly defined by these acrobatic outdoor stairs, which contort themselves to link the two, three, and even four levels of separate apartments to the street. Built in the 19th and early 20th century for multiple income levels, the plexes ranged from simple to ornate, though many housed large working-class families.

“Once known for affordability, Montreal has now joined Canada’s real-estate frenzy,” writes Sandrine Rastello of Bloomberg. Today, plexes are increasingly sought after as wealthy urbanites renovate and update, and architects and developers build contemporary interpretations of the form with up to six levels. 

Similar to New England’s triple-deckers, but tighter together and with stairs on the outside, there are many explanations for why a city as icy as Montreal developed a housing type with such steep external stairs. According to Rastello, the French-Canadian tradition of subdividing residential buildings for multiple families by adding an external stair predates the plexes of Montreal.

Indeed, on my own travels to Quebec, I saw similarly tall and twisting spirals stairs connecting the multiple levels of the provincial capital’s 18th and 19th-century buildings.

There are also theories that the ubiquitous external stair was the result of zoning changes that required a setback from the front property line. Seeking to maximize rentable space, homebuilders and architects used the setback for circulation. The trouble was, this minimal space was so shallow that the stairs had to twist in order to fit.

Regardless, zoning affects the work of tradespeople who construct and repair the designs of architects. My own grandfather, who arrived in Montreal from Italy in the 1950s, initially took up work on the metalwork for the city’s staircases. Indeed, the steep outdoor stairs that pervade the streets of Montreal have provided a canvas for generations of skilled craftsmen to twist, bend, and weld the elaborate iron that allows the people of Montreal to (carefully) get to their front door.