An Oshawa bungalow has four real ways to grow: open up the main floor, add a second storey, turn the basement into a registered second unit, or build a garden suite in the yard. Oshawa charges $7.79 per m² for interior finishing and $15.56 per m² for new living space as of October 2026, and its zoning allows 9.0 m of height and 40% lot coverage in the R1-A to R1-E zones. Which option fits depends on your lot, your basement and who's going to live there.
Key takeaways
- Oshawa's 2026 permit fee is $15.56 per m² for an addition or a habitable accessory building and $7.79 per m² for basement finishing, under Building By-law 33-2009.
- In the R1-A to R1-E zones of Zoning By-law 60-94, a house can be 9.0 m tall and cover 40% of the lot, or 45% with an accessory apartment.
- Oshawa issued 246 two-unit house registration certificates in 2023 and 338 in 2024, according to the Oshawa open data.
- All accessory buildings on an Oshawa lot, a garden suite included, are capped at 60 m² of ground floor (90 m² in R1-G and R1-H), per the Oshawa accessory apartment rules.
- A minor variance in Oshawa costs $856 per lot at the Committee of Adjustment.
- Starting work with no permit application adds a 50% surcharge to the Oshawa permit fee.
Which bungalow renovation fits your house?
Start with the problem, not the project. If the house feels cramped but has enough bedrooms, opening the main floor may be all it needs. If you need more bedrooms, you either go up or go out. If you need a separate home for a parent, an adult child or a tenant, it's the basement or the yard.
Here is how the four options compare in Oshawa, as of October 2026:
| Option | What you get | Oshawa permit fee | Rule to check first |
|---|---|---|---|
| Open the main floor | A bigger kitchen and living space in the same footprint | $7.79 per m² | Whether the wall is load-bearing (an engineer decides) |
| Add a second storey | Bedrooms and a bathroom upstairs, same lot coverage | $15.56 per m² | 9.0 m height limit in R1-A to R1-E |
| Basement second unit | A self-contained apartment with its own entrance | $7.79 per m² | One extra parking space per unit |
| Garden suite | A small separate house in the backyard | $15.56 per m² | 60 m² ground floor for all accessory buildings |
Note: fees are the City of Oshawa's 2026 rates per m² of floor area, before the minimum fee of $160; they are permit fees only, not construction costs. Zoning limits depend on your lot's zone.
Opening up the main floor of a bungalow
Most bungalows have a bearing wall running down the middle, between the kitchen and the living room. Taking it out is very doable, but it's structural work. A licensed engineer sizes a beam to replace it, the posts at each end carry point loads down to footings in the basement, and the ducts, wiring and sometimes a plumbing vent inside that wall have to go somewhere new.
It needs a building permit, and electrical changes go through the Electrical Safety Authority with a licensed electrical contractor. Our guide to removing a load-bearing wall covers beams, permits and the kitchen layout in detail. If you're doing the kitchen at the same time, our kitchen cost post has our 2026 ranges.
Adding a second storey to an Oshawa bungalow
Going up doubles your space without giving up the yard, and in Oshawa's R1-A to R1-E zones you have 9.0 m of height to work with. At $15.56 per m², a 1,000 sq ft (92.9 m²) second storey works out to a permit fee of about $1,446, calculated from the Oshawa fee schedule.
The fee is the easy part. The hard part is whether the foundation and main-floor walls can carry a new floor, which an engineer confirms, and where you'll live while the roof is off. Our 2026 range for a 600 to 1,200 sq ft second storey is $300,000 to $800,000 before HST, and any work on the main floor below adds to it. Our second storey planning guide walks through the structure, permits, zoning and HST rebate in Durham Region.
Turning the basement into a second unit
Basement apartments are common in Oshawa. The City issued 246 two-unit house registration certificates in 2023, 338 in 2024 and 251 from January 1 to November 26, 2025. Across Durham Region, Ontario, permits were issued for 999 additional residential units in 2024 and 1,004 in 2025.
When you build the unit through a building permit, Oshawa issues the two-unit house registration as part of the process. Units that existed before July 1994 are legalised through Municipal Licensing instead. The rules we plan around:
- Parking. One extra space for each accessory unit, so three spaces for a house with two units, each 2.75 m by 5.75 m, with 50% of the front yard kept as landscaped open space.
- Ceiling height. The Building Code asks for 1.95 m in a secondary suite, and 1.85 m under beams and ducts. Older bungalow basements sometimes fall short, which means lowering the floor or rerouting ducts.
- Fire separation. Between the units, the Code allows a continuous smoke-tight barrier of 15.9 mm Type X drywall on the walls and the underside of the floor framing in place of a rated assembly.
- Lot coverage. Oshawa raises the limit to 45% when the lot has an accessory apartment.
You don't pay development charges for a second unit in an existing house under the Development Charges Act. For scale, a new single detached house in Oshawa carries $130,682 in development charges. On cost, our 2026 range is $45,000 to $95,000 to legalise a basement that's already finished, and $80,000 to $180,000 for a full legal basement apartment. Our legal basement requirements guide goes deeper.
Building a garden suite behind an Oshawa bungalow
A garden suite suits a parent who wants their own door, or a bungalow on a deep lot. Oshawa counts it as an accessory building, and all the accessory buildings on the lot together can't exceed 8% of the lot area, 50% of the house's coverage or 60 m² of ground floor (90 m² in R1-G and R1-H). It can be 4.5 m tall, sit 0.6 m from the side and rear lot lines, and must be 3 m from the house. Your existing garage or shed counts against the same cap.
Oshawa allows a maximum of three units on the lot, with no more than one in an accessory building. So you can have the house, a basement unit and a garden suite, but not two suites in the yard. Good published cost data for Durham garden suites doesn't exist yet. The closest is Toronto, where permits list a median of $180,000 and the industry told the City real costs often exceed $300,000 to $400,000. See our garden suites page for how we build them.
What's specific to renovating in Oshawa
These are the Oshawa details that catch people, and that don't apply the same way in Whitby or Ajax:
- The zoning by-law. Oshawa works from Zoning By-law 60-94. Bungalows in the R1-A to R1-E zones get 9.0 m and 40%; larger-lot R1-F to R1-H zones allow 10.5 m.
- The Committee of Adjustment. If your plan breaks a zoning rule, five community members appointed by Council hear the minor variance, for $856 per lot.
- CLOCA. If the lot is in a fill-regulated area or floodplain, or the work could affect a watercourse, you need a Central Lake Ontario Conservation Authority permit as well. A minor permit for small additions is $535.
- The airport. Near the Oshawa Executive Airport, the City needs airport clearance before it issues a permit. That matters most for a second storey.
- Review times. Oshawa says record application volumes mean it cannot guarantee review timeframes. Ontario's Building Code sets 10 business days for a complete application on a house with no unit above another, and 15 for other small buildings, which can include a house with a basement unit.
- Building first, permit later. Oshawa adds a 25% surcharge when work starts after an application is in, and 50% when there's no application at all.
How we'd approach your bungalow
James comes out first and looks at the whole house: the basement height, the foundation, where the bearing walls run, the lot and the driveway. Often the answer is a mix, like opening the main floor now and roughing in for a basement unit, and it's cheaper to decide that before anything is drawn.
Ceara Jarvis's studio, Juliette Interiors, designs and draws it with us. A licensed engineer stamps the structure. We apply for the permit, the variance if one's needed and the CLOCA permit if the lot is regulated. One crew does the work, we book the inspections, and you get the registration or the closed permit at handover.
Our projects page shows finished work, and we're writing up more case studies now. The Greenwood project was a ten-month renovation in Toronto that we took through permit, design and construction.
Questions
Can I add a second floor to my bungalow in Oshawa?
You can add a second floor to most Oshawa bungalows if an engineer confirms the foundation can carry it and the new roof stays under the zoning height. In the R1-A to R1-E zones of By-law 60-94 that height is 9.0 m. Above it, you need a minor variance from the Committee of Adjustment, which costs $856 per lot.
How much is a building permit for a bungalow renovation in Oshawa?
An Oshawa building permit for a bungalow renovation is charged by floor area as of 2026: $15.56 per m² for an addition or second storey and $7.79 per m² for basement finishing. The minimum fee is $160. A 1,000 sq ft second storey works out to about $1,446.
How do I make a basement apartment legal in Oshawa?
A basement apartment becomes legal in Oshawa when you build it under a building permit, and the City then issues a two-unit house registration certificate. Units that existed before July 1994 go through Municipal Licensing instead. You'll need one extra parking space for the unit and a basement built to the Building Code's ceiling height and fire separation rules.
Can I have a basement apartment and a garden suite on the same lot in Oshawa?
You can have both a basement apartment and a garden suite on one Oshawa lot. The City allows up to three units on a lot, with no more than one in an accessory building. The garden suite has to fit within the accessory building limits, including 60 m² of ground floor for all accessory buildings outside the R1-G and R1-H zones.
Do I need CLOCA approval to renovate my Oshawa bungalow?
You need CLOCA approval for an Oshawa bungalow renovation only when the lot is in a fill-regulated area or floodplain, or the work could affect a watercourse. Interior work like opening a main floor usually isn't affected. Additions and garden suites on regulated lots are, and a minor CLOCA permit is $535.
Is it cheaper to renovate an Oshawa bungalow than to move?
Whether renovating an Oshawa bungalow beats moving depends on the house and the project, and nobody can answer it without numbers for both. Moving costs commission, legal fees and land transfer tax before you spend anything on the new house; the provincial tax alone on a $1.2 million house is about $20,475, calculated from Ontario's rates. Our renovate or move guide sets the two side by side.
If you'd like James to walk through your bungalow with you, contact us.
Sources
- $7.79 per m² for interior finishing and $15.56 per m² for new living space media-002-ca.cdn.govstack.com
- 9.0 m of height and 40% lot coverage media-002-ca.cdn.govstack.com
- Oshawa open data arcgis.com
- Oshawa accessory apartment rules oshawa.ca
- $856 per lot oshawa.ca
- licensed electrical contractor esasafe.com
- 999 additional residential units in 2024 and 1,004 in 2025 media-003-ca.cdn.govstack.com
- 1.95 m in a secondary suite publications.gov.on.ca
- Development Charges Act ontario.ca
- $130,682 in development charges oshawa.ca
- median of $180,000 toronto.ca
- Zoning By-law 60-94 oshawa.ca
- Central Lake Ontario Conservation Authority permit oshawa.ca
- $535 cloca.com
- Ontario's rates ontario.ca