Planning · 8 min read
What a legal secondary suite actually costs in Canada
Legal basement suite costs in Canada in 2026: fire separation, egress, CMHC refinance rules, and the MHRTC. Not the same job as finishing a rec room.
Finishing a basement and building a legal secondary suite are different projects that happen to occupy the same floor. A rec room needs drywall, a ceiling, and a bathroom if you want one. A legal suite needs a self-contained kitchen, a bathroom, a sleeping area, fire and sound separation from the rest of the house, legal egress from the bedroom, and usually a separate entrance. Many municipalities also want a separate electrical panel or sub-panel, and parking or landscaping that matches the zoning.
Our basement calculator prices finishing. Use it to understand the rec-room number, then add the suite-specific lines below. Confirm the current bylaw with your building department before you draw anything. This is not legal, tax, or mortgage advice.
What the work actually costs
From an unfinished basement in Toronto or Vancouver, a legal secondary suite commonly plans in the $80,000 to well over $150,000 range. The spread is almost entirely fire separation, a second kitchen, egress windows or a new entrance, and whether the existing ceiling height, plumbing stack, and moisture problems are already solved.
A finished rec room that already has a bathroom sits lower, because you are converting rather than building. A laneway or garden suite is a different product again, with foundation, servicing, and often a six-figure construction budget before the interior is fitted.
The lines a rec-room budget misses
- Fire-rated separations and self-closing doors between the suite and the principal dwelling
- Sound attenuation in ceilings and shared walls, which is a comfort requirement as much as a code one
- Egress: a bedroom window that meets size and opening rules, or a proper exit door
- A full kitchen, including range ventilation to the exterior
- A second electrical service or sub-panel, smoke and CO alarms, and often a second heating zone
- A separate entrance, stairs, and exterior work, including drainage at a new door
- Drawings, engineering, permit fees, and extra inspections
- Parking, landscaping, or servicing upgrades if zoning requires them
CMHC suite refinance: status uncertain
In January 2025, CMHC began insuring a refinance product for homeowners adding a self-contained secondary suite. Its status is now uncertain. A mortgage broker reported in late 2025 that it ended after Budget 2025, and we have not been able to confirm it is still offered. Confirm with your lender before you plan around it. As originally published, the outline was: you already own the home; you or a close relative live in it; the new suite is self-contained and not used as a short-term rental of less than 90 days; the extra money is for construction and completion only; the as-improved value must be below $2 million; owner-occupied properties of up to four units could go up to 90 percent loan-to-value; amortization could run 30 years; and debt-service ratios were capped around 39 percent GDS and 44 percent TDS, with a minimum credit score of 600 on at least one borrower.
Even where it is offered, that product does not make an illegal basement legal. Lenders still want permits, and the suite still has to comply with the local bylaw. A HELOC or a conventional refinance remains the path when the property is over the value cap, the occupancy test fails, or you are not adding a unit.
The multigenerational home renovation tax credit
The federal MHRTC is a refundable credit for creating a self-contained secondary unit so a senior aged 65 or older, or an adult eligible for the disability tax credit, can live with a qualifying relative. For the 2025 tax year, CRA's published figures are 14.5 percent of up to $50,000 in qualifying expenditures, for a maximum credit of $7,250 per qualifying renovation. Those are 2025 figures. The credit follows the lowest federal tax rate, so a renovation finished in 2026 likely earns 14 percent, or up to $7,000, though CRA has not published the 2026 figures yet. You claim it in the year the renovation is completed, on line 45355 with Schedule 12.
A rental suite for a tenant who is not a qualifying relative is not this credit. Confirm eligibility, eligible expenses, and the year of completion on Canada.ca before you treat it as money in the budget. It is not tax advice, and a credit of about $7,000 does not fund an $80,000 suite.