Oshawa · Rental Income, Done Legally

Legal Basement Apartment in Oshawa

Can you legally rent out your basement in Oshawa? Yes — and it's one of the smartest things you can do with space you already own. It can help pay your mortgage. Or give family their own place. The trick is doing it legally, so it earns you money, not a fine. Here's what Oshawa asks for, in plain words.

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Oshawa at a Glance

3Units allowed on most lots
3Parking spaces total for a two-unit home
50%Of the front yard stays landscaped
60Days to automatic registration after final inspection

The #1 Thing That Stops a Project

Oshawa's Parking Math

More Oshawa basements get stopped by parking than anything else. The rule is simple, but not every driveway fits it — so we check it on the first visit, before you spend a dollar.

2
Main home
+
1
The suite
=
3
Total spaces
  • Each space must be at least 2.75 m × 5.75 m (about 9 ft × 19 ft).
  • Two of the three need a clear path to the street — they can't all be single-file. The third may be tandem.
  • At least one space must sit in a side yard, rear yard, or garage.
  • Making a space street-accessible often needs a curb cut, approved by the City or the Region of Durham.

Rule Book 1 · Oshawa Zoning

The Rest of the Local Rules

Beyond parking, these are the property-level rules under Zoning By-law 60-94 that decide whether your lot works.

Landscaping & Lot

  • At least 50% of the front yard must stay landscaped — you can't pave it all for parking.
  • A hard-surface walkway at least 0.81 m (32 in) wide from the suite entrance to the street.
  • Up to 3 units per lot, one of which may be in an accessory building (garden suite).
  • Minimum lot frontage varies by zone — we confirm yours during planning.

Location Limits

  • The suite can't be on hazard lands flagged by CLOCA (the conservation authority).
  • Lots near an MTO highway corridor (401/407) or a Metrolinx transit corridor may need separate approvals.
  • If your lot just misses a rule, a minor variance through the Committee of Adjustment can often still make it work.

A legal suite is fully self-contained — its own kitchen and bathroom, built to the standard of our kitchen renovations in Oshawa and bathroom renovations in Oshawa, with the same structural and beam work we use to open up a basement.

Rule Book 2 · Inside the Suite

What the Building Code Requires

The Building Code sets the safety rules inside the suite — the same across Ontario. Here's what matters most in a basement:

The Essentials

  • Ceilings at least 1.95 m (6 ft 5 in), dropping to 1.85 m under beams and ducts. Low headroom is the most common thing that needs design work first.
  • An escape window in every bedroom — big enough to climb out of in a fire.
  • Fire separation between your suite and the unit above.
  • Hard-wired, interconnected smoke and carbon-monoxide alarms — and as of January 1, 2026, a CO alarm on every storey.
  • Minimum room sizes so the space is genuinely livable.
See the full room-by-room size table in our Durham guide

How It Works

Permitted, Inspected, Registered

A legal suite isn't just built — it's permitted, inspected, and registered. We carry all of it.

1

Confirm Your Zoning

Zone, frontage, the parking math and any CLOCA, MTO or Metrolinx considerations — checked before we design.

2

Design & Drawings

Scaled plans showing room areas, egress, fire separation and alarm locations, to Oshawa's standards.

3

Building Permit

Filed through Oshawa's portal as an added dwelling unit. Required for any second unit created after July 1994.

4

Build & Inspections

Built to code and passed through fire separation, egress, plumbing and electrical inspections to final sign-off.

60

Automatic registration. Build it through the permit process and it's registered as a two-unit house — your certificate is issued within 60 days of the final inspection. (A suite built before July 1994 follows a separate legalization path — we'll tell you which applies.)

Why Build It Legal

A Registered Suite Is Worth More

Real Income

A registered unit rents with confidence — tenants can even verify it with the City — and the rent counts on a mortgage.

Resale Value

Officially a two-unit house — worth more and simpler to sell. Buyers aren't inheriting an unpermitted risk.

Safe & Insured

Code fire separation, egress and alarms protect your tenants and your home — and keep your insurance valid.

Built Once

An unpermitted suite can be ordered closed and torn out. Done legally the first time protects it for good.

Common Questions

Oshawa Basement Apartment FAQ

How many units can I have on my Oshawa lot?
Up to three residential dwelling units per lot under By-law 60-94, of which a maximum of one accessory unit may be located inside an accessory building (such as a garden suite or converted garage). We confirm your specific lot on the first visit.
Do I really need extra parking?
Yes — one more space for the suite, bringing a two-unit property to three total, each at least 2.75 m × 5.75 m, with two having unobstructed street access. It's the single most common reason a basement can't be legalized, so we check it before anything else. Creating those spaces sometimes needs an approved curb cut.
My basement ceiling feels low — is that a dealbreaker?
Not necessarily. The Code requires about 1.95 m (6 ft 5 in) across living areas, dropping to 1.85 m under beams and ducts. Many Oshawa basements qualify; where they're tight, design choices (relocating ducts, adjusting the layout) often solve it. We assess this early so there are no surprises.
Does the suite get registered automatically?
When you create the unit through the building-permit process, it's registered as a two-unit house and you receive your certificate within 60 days of the final inspection. A suite built before July 1994 follows a separate legalization path through Municipal Licensing & Standards.
My basement was finished before I bought the house — is it legal?
Not automatically. Units built before July 1994 follow a different legalization path (a registration application, a $500 fee and a declaration), and newer unpermitted work usually needs to be brought up to Code. We'll assess exactly what you have.
What affects the cost of a legal basement apartment?
Ceiling height and whether the floor needs lowering, a separate entrance, egress windows, parking and curb-cut work, the kitchen and bathroom layout, fire separation, and electrical/HVAC separation all drive cost. After a site visit we give you a clear, locked scope and price — not a guess.
Bylaw information last reviewed July 2026. Municipal requirements can change — Cornerstone confirms current City of Oshawa requirements with the building department on every project. Sources: City of Oshawa Accessory Apartments & Two-Unit Houses pages; Zoning By-law 60-94; Ontario Building Code.
Part of Our Durham Legal Suites Guide
See requirements for every Durham town, plus the full second-suite overview
Back to Hub →

Also building legal suites in Whitby, Clarington, and across Durham Region.

Thinking About a Basement Suite in Oshawa?

Start with a free basement check. We'll run the parking math on your lot, tell you straight if it works, and give you a clear, locked price. Built once, built right.

Start Your Basement Diagnostic Call 1-888-404-7383

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