- $1,500–$2,050Typical monthly rent for a legal 1 or 2 bedroom basement unit in Durham in 20261
- 90%CMHC-insured refinancing of your home's value after the suite is built2
- 3 unitsAllowed on most urban residential lots in Ontario without rezoning3
- No capOn annual rent increases for units first occupied after Nov. 15, 20184
Why a legal suite is a strong investment right now.
Treat your basement like any other investment: steady demand, favourable rules, and financing designed for exactly this.
Renters want exactly this
Durham keeps growing as people leave Toronto for more space. In mid-2026, one-bedroom apartments in Oshawa averaged around $1,600 to $1,750 a month and two-bedrooms around $2,000.1 A bright, legal basement unit with its own entrance competes directly for those renters.
The province wants you to build it
Ontario's More Homes Built Faster Act lets most urban homeowners add up to two extra units without a rezoning application, and those extra units don't pay development charges.3 Your municipality still requires a building permit, which we handle.
Financing is built for suites
Since January 2025, CMHC-insured refinancing lets owner-occupiers borrow up to 90% of the home's value once the suite is finished, over up to 30 years, on homes valued under $2 million.2 Many homeowners fund the whole build this way.
New units set their own rent
A basement unit first lived in after November 15, 2018 is exempt from Ontario's annual rent increase guideline, which is 2.1% for 2026.4 Normal notice rules still apply, but your rent can keep pace with the market.
See what a suite does to your mortgage.
Pick your town and unit, enter your mortgage payment, and see how much a tenant could cover. Every number updates as you go.
Your tenant covers 0% of your mortgage.
After vacancy, upkeep and costs
Before income tax
Yearly net income ÷ build cost
From rent alone
See the breakdown
Estimates only, for planning. Rents are typical 2026 asking rents for legal basement units and vary with finishes, size, light and the exact street. The model sets aside 4% for vacancy and 5% of rent for maintenance. Rental income is taxable, and many costs are deductible; talk to an accountant and a mortgage professional about your situation. This is not financial advice.
What one looks like when we're done.
An unfinished Oshawa basement turned into a self-contained two-bedroom apartment with a full kitchen, full bathroom, powder room and laundry.
- Size
- About 1,200 sq ft
- Build budget
- $90,000 – $120,000
- Time on site
- 8–10 weeks
- Rents for
- About $2,250 a month
Why legal, not just finished.
An unpermitted apartment can void your insurance, block refinancing, and cost you at resale. A legal one is an asset lenders, insurers and buyers recognize. Here is what makes a unit legal in Ontario.
- Building permit and inspectionsDrawings approved by your municipality, with inspections at each stage.
- Fire separationFire-rated ceilings and walls between the units, and interconnected smoke and CO alarms.
- A safe way outAn exit that meets code, plus egress windows in bedrooms.
- Its own entranceA separate or properly protected entrance for the tenant.
- Ceiling height and lightMinimum ceiling heights and window area for living spaces.
- Heating, ventilation and electricalSafe heating, proper ventilation, and a panel that can carry both units.
From basement to income in four steps.
Most legal suites take about two months on site once the permit is issued. Permit timing depends on your municipality.
1. Site visit and numbers
We check ceiling height, windows, entrance options and your panel, then give you a written price and a rent estimate.
2. Design and permit
We draw the layout to code and handle the permit application with your municipality.
3. Build and inspections
Licensed trades build it, and inspectors sign off at each stage.
4. Ready to rent
You get a finished, legal unit with the permit records that prove its rent-control exemption.
Find out what your basement could earn.
We'll visit, check what your basement needs to be legal, and give you a written price and a realistic rent estimate. Free.
Sources
- Rent estimates are ours, based on Durham rental listings and rent reports from Rentals.ca and Zumper, July to September 2026. Basement units usually rent slightly below above-grade apartments.
- CMHC mortgage insurance for secondary suites, effective January 15, 2025: owner-occupied homes of up to four units, up to 90% of the as-improved value, amortization up to 30 years, value under $2 million. The separate $80,000 Canada Secondary Suite Loan Program announced in 2024 was cancelled in Budget 2025 and never opened.
- Ontario More Homes Built Faster Act, 2022. Local zoning and building rules still apply; confirm with your municipality.
- Government of Ontario, residential rent increase guideline: 2.1% for 2026; new units first occupied for residential purposes after November 15, 2018 are exempt.