VANPLEX
David Babakaiff
Written by David Babakaiff — Co-Founder, VanPlex | 25+ Years BC Construction

Ottawa Areas | Inner City

Missing Middle in Old Ottawa South

Old Ottawa South is a mature, compact neighbourhood in Capital Ward, set between the Rideau Canal and the Rideau River (neighbourhood profile). The lots are older and smaller than the suburbs. Under four units as-of-right, a multiplex is permitted, and here the real question is whether it fits the lot.

A modern infill triplex between older narrow red-brick homes on a tree-lined Old Ottawa South street

What Old Ottawa South Lots Look Like

Older, smaller inner-city lots

Old Ottawa South is a mature, compact neighbourhood of about 7,000 residents in Capital Ward. The housing is mostly single-detached with semis and modest infill on narrow inner-city lots.

Between the canal and the river

The neighbourhood sits between the Rideau Canal to the north and the Rideau River to the south, with Bronson Avenue on the west and Avenue Road on the east. Bank Street is the walkable commercial spine.

Infill is already happening

Compared to other central neighbourhoods it has seen little high-rise, but modern infills are increasingly common. The new zoning makes small multiplex infill a clearer path than the case-by-case fights of the past.

This is land where value sits in location, not lot size. The streetcar-era street grid produced narrow lots, so the constraint on a multiplex is usually frontage and coverage, not the unit cap. The 2026 by-law turns infill that once meant a case-by-case fight into a clearer as-of-right path when the geometry works.

Which N-Zone, and Whether It Fits

The March 2026 reform replaced the old R-zones with size-based Neighbourhood (N) zones. Most of the residential interior is the base N1 zone with the four-unit baseline; lots closer to Bank Street can sit in higher N-zones. On a narrow inner lot, the binding question is the size envelope: frontage, lot area, setbacks, and coverage. Work the numbers before assuming four units fit. Confirm your zone and its standards on geoOttawa.

Best For

  • ✓ Owners of a serviced inner-city lot who want infill without a rezoning.
  • ✓ Builders who can design a multiplex form to a narrow lot envelope.
  • ✓ Anyone weighing a high-location, small-lot infill over a wide suburban site.

Usually Fails When

  • ✕ The lot is too narrow or small to fit four units to the N-zone standards.
  • ✕ A heritage designation or conservation overlay restricts the build.
  • ✕ You assume four units fit without checking frontage and coverage limits.

What To Verify Before Spending Money

  • → Your Neighbourhood (N) zone and its frontage and lot-area minimums on geoOttawa.
  • → Whether the multiplex form meets setbacks, height, and coverage without a variance.
  • → Whether any heritage or conservation overlay applies to the lot.

Frequently Asked Questions

Can I build a fourplex in Old Ottawa South? +
Yes, in principle. Ottawa Zoning By-law 2026-50 allows up to four units as-of-right on a serviced residential lot, and Old Ottawa South is fully serviced. The real test is fit: these are older, narrow inner-city lots, so four units must still meet the Neighbourhood (N) zone's frontage, setback, and coverage standards.
Do Old Ottawa South's small lots fit four units? +
Sometimes. The four-unit permission applies, but a narrow inner-city lot can run short on frontage or lot area to fit four units inside the zone standards. Removing parking minimums helps. Where four units do not fit, three or a duplex-plus form may be the buildable answer. Check the standards on geoOttawa.
What zoning applies to an Old Ottawa South multiplex? +
Lots fall under the size-based Neighbourhood (N) zones that replaced the old R-zones in March 2026. Most of the residential interior is the base N1 zone with the four-unit baseline. Lots closer to Bank Street can sit in higher N-zones allowing more. Confirm the exact zone on geoOttawa.
Do I need parking for an Old Ottawa South fourplex? +
No minimum is required. By-law 2026-50 removed minimum parking requirements city-wide. On the small, often laneless lots common here, dropping the parking requirement is frequently what makes four units physically fit at all.
What can I build in Old Ottawa South if a fourplex does not fit my lot? +
Three units or a duplex-plus form can be the buildable answer. Old Ottawa South's narrow, streetcar-era lots sometimes run short on frontage or lot area for four full units inside the Neighbourhood (N) zone standards. Where the geometry does not work for four, a smaller unit count on the same lot often still clears the standards.
Does a heritage designation affect a multiplex build in Old Ottawa South? +
It can. A heritage designation or conservation overlay on a specific lot restricts what can be built there, separately from the Neighbourhood (N) zone rules. Old Ottawa South has seen little high-rise but growing infill, so check for a heritage or conservation overlay on the parcel before assuming the by-law's as-of-right permission applies without limits.
Is Old Ottawa South a good place to build a multiplex compared to a suburban lot? +
It depends on what you value. Old Ottawa South offers a high-location, small-lot infill site inside Capital Ward, between the Rideau Canal and the Rideau River, near the Bank Street commercial spine. A wider suburban lot elsewhere in Ottawa gives more room to fit a fourplex, but Old Ottawa South's location is the reason land here holds its value.
How many people live in Old Ottawa South, and does that affect infill approval? +
Old Ottawa South has about 7,000 residents and is a mature, compact neighbourhood in Capital Ward. Population size itself does not change the as-of-right permission under By-law 2026-50. What matters for approval is whether the specific lot meets the Neighbourhood (N) zone's frontage, setback, and coverage standards.

Next: test whether four units fit your specific lot with the feasibility guide, or start at the Ottawa Missing Middle hub.

Official Sources Referenced

City of Ottawa: New Zoning By-law (Engage Ottawa)
https://engage.ottawa.ca/zoning
City of Ottawa: Council approves landmark new Zoning By-law (Jan 28, 2026)
https://ottawa.ca/en/city-hall/city-news/newsroom/council-approves-landmark-new-zoning-law-enable-housing-and-economic-development
City of Ottawa: New Zoning By-law 2026-50 (provisions and map)
https://ottawa.ca/en/planning-development-and-construction/zoning/new-zoning-law
Bill 23, More Homes Built Faster Act, 2022 — Legislative Assembly of Ontario
https://www.ola.org/en/legislative-business/bills/parliament-43/session-1/bill-23
Province of Ontario: More Homes Built Faster Act overview
https://www.ontario.ca/laws/statute/s22021
CMHC: Housing Markets, Data and Research
https://www.cmhc-schl.gc.ca/professionals/housing-markets-data-and-research
Statistics Canada: Census of Population — Housing
https://www12.statcan.gc.ca/census-recensement/2021/ref/index-eng.cfm
Opticos Design: Missing Middle Housing (origin of the term)
https://missingmiddlehousing.com/
General information, not legal advice. Zoning and permitting rules are set by the City of Ottawa and the Province of Ontario, and both change over time. Verify current requirements directly with the City of Ottawa Planning Department before making a decision.

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