Housing supply is a cumulative exercise because even at very fast growth rates most houses already exist. Montreal doesn't build a ton of low-rise anymore, but they also don't have much land left and the economics that produced their plex system of small apartment blocks has changed dramatically over the past 125 years when they were most popular (just like anywhere really where the times keep on changing).
Below at 2021 numbers for Montreal and Calgary, I dropped some of the less important housing types. Montreal suburbs are excluded here, just the city only - that probably downplays the number of single homes as the suburbs have more, but for this analysis is it's not that important.
The main takeaway - while Monteal doesn't build a ton of low-rise anymore, they will always have such a weight and existing supply it will never feel like it. To contextualize just home much existing volume of low rise Montreal has in an unrealistic scenario, if Montreal never built another low rise unit and Calgary built 6,000 low rise a year (or about 500 a month as is the pace lately), we'd only reach their 2021 supply number of low rise in 2084, in time for Calgary's 200th anniversary!
Type, 2021 data | Calgary (city) | Calgary % | Montreal (city) | Montreal % |
Single +Duplex | 297,215 | 59% | 165,630 | 20% |
Low rise (Semi-detached, row, apartment under 5 storeys) | 164,180 | 33% | 516,335 | 64% |
5+ Storeys | 40,700 | 8% | 130,615 | 16% |
Total | 502,095 | 100% | 812,580 | 100% |