In Calgary, "duplex" gets used loosely — the DDF® feed exposes a single PropertyAttachedYN flag that captures side-by-side duplexes, semi-detached homes and half-duplex infills together. This page filters to attached single-family properties that also carry a legal secondary suite.
Why the "attached" filter is broader than "duplex"
A true side-by-side duplex, an attached infill, and a semi-detached home are all marketed differently but share the same DDF® attribute. We show them together and flag the property sub-type on each card so you can distinguish quickly. If you need side-by-side specifically, confirm the configuration with the listing agent or on the plot plan before booking a showing.
The three-door setup
The most common legal-suite duplex in Calgary is a three-door infill: an upper unit on each side with a shared or separate legal basement suite. Rent scales quickly, but the capital cost and lot-yield economics differ from a detached legal-suite home — the mortgage-helper home page is a better fit if you're occupying one side.
Watch for
- Firewall / party-wall assemblies rated to current code.
- Separate utilities per unit vs. sub-metered.
- Individual civic addresses and Secondary Suite Registry entries.
- Land-use district and any bare-land condo declaration.
LegalSuites.ca reads CREA DDF® listing remarks and structured fields to interpret each listing's suite status. That is a lead for discovery — not a legal determination. Before writing an offer, confirm any suite against the City of Calgary secondary-suite information page and its Secondary Suite Registry, and engage a licensed REALTOR® and Alberta-qualified inspector.
