Montreal’s zoning regulations determine what you can build, buy, or convert on any given lot. For plex investors, understanding these rules is the difference between a profitable acquisition and a costly mistake. Here’s your 2026 guide to navigating the system.
🏗️ Montreal Zoning Categories Explained
RH — Residential
RH-1: Single-family only
RH-2: Duplexes allowed
RH-3: Up to triplexes
RH-5: Up to 5-plexes
RM — Mixed Residential
RM-1: Low density (2-3 storeys)
RM-2: Medium density (3-4 storeys)
RM-3+: High density (5+ storeys)
Often allows ground-floor commercial
Each borough has its own urban plan (Plan d’urbanisme) that maps these zones at the lot level. You can check any address on the City of Montreal’s online zoning map. The zoning code appears on the property’s certificate of location and determines what type of building is permitted.
📍 Where Plexes Are Allowed
Plexes are concentrated along Montreal’s main arterial streets and in the central boroughs. RH-2 and RH-3 zones dominate the Plateau, Rosemont, Villeray, and Mercier–Hochelaga-Maisonneuve. Roughly 60% of Montreal’s residential land permits multi-unit dwellings of some form.
Suburban boroughs (Pierrefonds, Kirkland, L’Île-Bizard) are predominantly RH-1 single-family zones. Laval and the South Shore have their own independent zoning frameworks. Always verify zoning before making an offer—a property listed as a “duplex” may be a non-conforming use if the zoning has changed.
🔄 Conversion Rules and CCU Permits
⚠️ Converting a single-family home into a duplex or triplex requires the property to be in a zone permitting that density. No amount of permits can override zoning.
If zoning permits it, you need a CCU (comité consultatif d’urbanisme) approval for conversion. The process involves submitting architectural plans, a public consultation period (30 days), and borough council review. Typical timeline: 3-6 months. Fees range from $500-$2,000 depending on the borough.
Key requirements for conversion: separate entrances for each unit, fire separation between floors (1-hour fire rating minimum), adequate parking (varies by borough—typically 0.5-1 space per unit), and compliance with the Quebec Construction Code. Budget $80,000-$150,000 for a single-family to duplex conversion in 2026.
📊 Key Investment Zones in 2026
Rosemont–La Petite-Patrie
$850K-$950K
Median duplex/triplex. Strong rental demand, proximity to metro, mostly RH-3 zoning.
Villeray–Saint-Michel
$750K-$880K
Most affordable central plex market. Blue line metro extension will boost values 10-15%.
Saint-Michel
$680K-$800K
Up-and-coming area. Lower entry prices, RM zoning along major streets, strong rental yields.
These three sectors combine favourable zoning (RH-3 to RM-2), strong rental demand from proximity to universities and transit, and prices still below the Montreal island median for plexes (~$855K in early 2026). Investors targeting a GRM (gross rent multiplier) under 15x should focus on Saint-Michel and northern Villeray.
🏢 Height, Density Limits and Value Impact
Montreal regulates building height (typically 9-12 metres for RH zones, up to 20+ metres in RM-3+), lot coverage (60-80% maximum), and floor area ratio (FAR). A property zoned RH-3 with unused density (e.g., a bungalow on a lot that permits a triplex) represents a significant upside opportunity.
Properties with higher-density zoning command a 15-25% premium over comparable properties in RH-1 zones. In 2026, the City of Montreal continues to encourage densification along transit corridors, and some boroughs are rezoning areas near future REM and metro stations to permit higher density—creating value for early investors.
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