How Much Does a Garden Suite Cost in Toronto & the GTA?

Prefab / Modular Suite

$225,000 - $300,000

~400 - 550 sq ft

Factory-built panels or modules finished on site. The fastest, most budget-predictable route to a one-bedroom suite — site costs (foundation, servicing) still depend on your lot.

Custom 1-Bedroom

$285,000 - $400,000

~450 - 645 sq ft

A single-storey custom suite designed for your lot, with a full kitchen, laundry, and finishes chosen for their purpose — rental durability or family comfort. The most common build.

Two-Storey / 2-Bedroom

$400,000 - $520,000

~800 - 1,100 sq ft over 2 floors

Where the lot's setbacks and angular planes allow the height, a second storey nearly doubles living space on the same footprint. Higher cost reflects added structure, stairs, and mechanicals.

The build (hard costs)

The physical construction of the suite — usually 75 to 85 percent of the total, scaling directly with size and finish level.

• Excavation and foundation
• Framing, roofing, windows, and exterior cladding
• Mechanicals — plumbing, electrical, heating, and ventilation
• Insulation, drywall, and interior finishes
• Kitchen, bathroom, flooring, and fixtures

Everything else (soft costs & connections)

The items construction-only quotes quietly exclude. On our quotes these are included in the all-in number.

• Land survey — around $2,000
• Architectural design and structural engineering
• Building permit fees and application management
• Arborist report and tree protection, where required
• Servicing trenched from the main house (water, sewer, hydro)
• HST on the project

Servicing Distance

Water, sewer, and hydro are typically trenched from the main house out to the suite. The further the connection has to travel across the yard — and the more hardscaping in the way — the more trenching, materials, and labour are required. Long servicing runs are the biggest hidden cost driver.

Site Access

Crews and equipment need a way into the backyard. A wide side yard keeps costs down, while a narrow gap between houses can mean hand-digging, smaller equipment, and craning materials over the home — all of which add to the budget.

Trees, Grading & Drainage

A flat, well-drained lot with no protected trees is straightforward. Protected trees can shift the suite's position or foundation type, and sloped or poorly drained sites can require retaining walls or grading work before the suite is even framed.

Finish Level

The same footprint can be finished as a durable rental or a high-end family suite. Cabinetry, flooring, tile, fixtures, and windows are where finishes swing the total from the low end of the range to the top.

One Storey vs Two

A second storey adds structure, stairs, and a more complex roof and mechanical layout, pushing all-in cost toward $520,000 at the top of the range. It can still be the efficient choice when your buildable footprint is limited.

Custom vs Prefab

Prefab and modular suites start around $225,000 and compress timelines, but offer less design flexibility. Custom builds fit awkward lots and specific needs precisely. Our prefab cost guide compares the two paths honestly.

City of Toronto

Garden suites have been legal citywide since February 2022, capped at 60 m² of floor area and up to two storeys where setbacks and angular planes allow. Narrow-lot access and tree protection are the common cost variables; rents are the region's strongest.

Central Toronto Laneways

Lots backing onto a public laneway build laneway suites instead — permitted since 2018, typically two-storey, and priced at a premium for tight-site logistics. See our laneway suite cost guide for the $320,000 to $520,000 range.

York, Peel & Durham

Under Bill 23 and O. Reg. 462/24, up to three units are as-of-right on most residential lots, and each municipality sets its own suite envelope — some allow larger suites on bigger lots. Generous suburban yards often mean easier access and shorter trenches.

Halton & Hamilton

The same provincial framework applies, with municipal bylaws setting size and setback limits. Larger lots in Burlington, Oakville, Milton, and Hamilton can support generous single-storey suites; development charges are waived for qualifying units in most municipalities.

Insured Mortgage Refinance

Since 2025, qualifying homeowners can refinance up to 90% of their property's as-improved value specifically to add a secondary suite. Applied as the largest, cheapest layer of a funding stack, it can meaningfully cut the borrowing cost of a garden suite build. Eligibility criteria apply.

Multigenerational Home Renovation Tax Credit

A refundable federal credit worth 15% of up to $50,000 in eligible costs — up to $7,500 back — when the suite is built for a senior (65+) or an adult eligible for the disability tax credit. One claim per eligible person.

Development Charges Waived

Development charges are waived for additional residential units in most municipalities, removing a fee that would otherwise add tens of thousands of dollars to a new detached dwelling. We confirm the application for your municipality during feasibility.

HELOC or Mortgage Refinance

Home equity funds the bulk of most builds — a HELOC drawn against construction milestones, a refinance for a lump sum at mortgage rates, or a blend. Lenders will want a fixed-price contract for a permitted project, which our all-in quotes provide.

Rental Income

One-bedroom garden suites in the GTA typically rent for $1,900 to $2,600 per month — a long-term rental unit on land you already own, without buying a separate property. Payback on rent alone generally runs 12 to 18 years, before appreciation. We never guarantee a figure, but income is the most common reason owners build.

Multigenerational Living

Many families build for aging parents or adult children — private, self-contained, and steps from the main house. The MHRTC can return up to $7,500 in qualifying cases, and the avoided cost of retirement housing or rent elsewhere is often the strongest return of all. See our in-law suites page.

Added Property Value

A second dwelling and an income stream both contribute to a property’s value, though the impact varies by market. For a full breakdown of rents by area, payback timelines, and resale, read our garden suite rental income & ROI guide.

Keep the Footprint Simple

A clean rectangular plan is cheaper to build than one with lots of corners, offsets, and roof complexity. Simple shapes use materials efficiently and frame faster, which lowers both labour and material cost.

Shorten the Servicing Trench

Positioning the suite to minimize the distance water, sewer, and hydro must travel from the main house reduces trenching and connection cost. A feasibility review identifies the most cost-effective placement on your lot.

Start with Feasibility

A zoning and site review up front prevents expensive redesigns later. Knowing your size, height, setback, tree, and access constraints before drawings begin keeps the project on budget from day one.

Consider Prefab

Prefab and modular suites start around $225,000 and compress on-site construction to 10-16 weeks. If a standard plan fits your lot and needs, the savings are real — compare honestly in our prefab cost guide.

Choose Durable Mid-Range Finishes

For a rental suite, durable mid-range finishes often beat premium ones on value. They cost less up front, hold up to tenants, and rarely change what you can charge.

Build the Incentives Into Your Budget

Insured mortgage refinancing up to 90% of as-improved value, the MHRTC, and waived development charges can shift your net cost meaningfully. Factor confirmed programs in early — see our financing guide — rather than treating them as a bonus.