What a legal secondary suite actually costs in Canada

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 refinance for building a suite

Since January 2025, CMHC has insured a refinance product aimed at homeowners adding a self-contained secondary suite. The details change, so read the current CMHC page and talk to a lender. As of 2026 the published outline is: 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 can go up to 90 percent loan-to-value; amortization can run 30 years; and debt-service ratios are capped around 39 percent GDS and 44 percent TDS, with a minimum credit score of 600 on at least one borrower.

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. 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 $7,250 credit does not fund an $80,000 suite.