Modular Homes & Garden Suites in Markham, Ontario

Getting your building permit in Markham

An eligible lot still needs a building permit before anything is delivered. Here's how Markham's process actually works — verified against the Markham building department's own pages.

How do you apply for an ADU building permit in Markham?

Through ePLAN (City of Markham online permit portal) (application portal ↗). All building permit applications must be submitted online through Markham's ePLAN portal — paper applications are no longer accepted. A non-refundable $100 pre-application fee is paid before drawings can be uploaded, and the official 'date of application' is the date Pre-Screen review is approved, not the date you upload. Markham's building-permit page ↗

1. Confirm your lot allows a garden suite under Comprehensive Zoning By-law 2024-19 — Markham offers an optional paid Zoning Preliminary Review ($315 for low-rise, two review cycles included) to verify zoning compliance before you apply
2. Line up any 'applicable law' approvals flagged on the City's Applicable Law Checklist — for example a conservation authority (TRCA) permit on regulated valley or floodplain lots, or a Heritage Permit if you're in one of Markham's four heritage conservation districts
3. Create an ePLAN account, start a housing (HP) permit application for the garden suite, and pay the non-refundable $100 pre-application fee to unlock drawing upload
4. Upload your forms and drawings per the ePLAN Submission Standards and pay the estimated permit fee in full — staff run a Pre-Screen review to confirm the package is complete, and Pre-Screen approval sets your application date
5. Plans review runs in electronic cycles with email notifications — respond to examiner comments and resubmit revisions until approval; any fee balance owing must be paid before the permit is issued
6. Download the issued permit, print the permit card and one set of approved plans for the jobsite, then build and call in inspections at the required stages
7. Once the property has a second dwelling unit, register it with Markham Fire & Emergency Services (two-unit registration — confirm with the City how this applies to a detached suite)

What does a Markham ADU permit application need?

• ePLAN application (replaces the paper Building Permit Application Form) plus Permit Applicant Authorization if the owner isn't the applicant
• Applicable Law Checklist (conservation authority, heritage and other approvals required by applicable law)
• Schedule 1: Designer Information (BCIN-qualified designer)
• Energy Efficiency Design Summary Form
• Site plan with a zoning summary (permitted vs proposed), property lines referenced to a current survey, and locations/dimensions of all existing and proposed buildings
• Floor plans of every level showing rooms, plus electrical layout — lighting, switches, outlets and interconnected smoke alarms
• Building elevations with limiting-distance calculations, including the face of the existing house toward the garden suite
• Sections with wall/ceiling/fire-separation construction details, stair/guard/handrail details
• Structural (foundation and framing) designs and HVAC plans with heat loss/gain calculations

How much does an ADU building permit cost in Markham?

Expect roughly $1,300–$2,200 in City permit fees for a ~600 sq ft (56 m²) detached garden suite — Markham's 2026 residential rate is $22.08–$24.75 per m² (a garage-with-dwelling-unit/coach house is a flat $2,062) under Building By-law 2025-121, plus the $100 ePLAN pre-application fee and about $250 for plumbing — an estimate; the City verifies the exact fee during plans review and confirms the current rate at application.

Ontario's provincial rules mean development charges are not collected for qualifying additional residential units (Bill 23 extended ARU relief). Markham's own development-charges page doesn't publish an ADU-specific exemption note, so confirm the detached garden-suite treatment with Markham Development Finance (905-477-7000 ext. 3324) before budgeting.

How long does an ADU building permit take in Markham?

Ontario's Building Code requires a decision on a complete house-class application within 10 business days. Markham's published service standard for houses is 10 business days from Pre-Screen approval for a complete application; incomplete applications run roughly 20–40 business days, and each plans-review resubmission cycle adds time.

Registration: Markham requires two-unit houses (secondary suites) to be registered with Markham Fire & Emergency Services — $246 per registration plus a $260 fire inspection under User Fee By-law 2025-125; occupying an unregistered two-unit house can result in court action and fines. The published registration program is framed around basement apartments/second suites, so confirm with the City how registration applies to a detached garden suite.

Worth knowing before you apply

• ePLAN-only: paper applications are not accepted, a non-refundable $100 fee is due before you can even upload drawings, and the 10-day review clock starts at Pre-Screen APPROVAL — an incomplete upload doesn't start the clock
• A garden suite is a 'housing (HP)' permit class with fuller drawing requirements than a shed-type accessory building — including electrical/smoke-alarm layouts, fire-separation sections, and elevations with limiting-distance calculations showing the house face toward the suite
• The Applicable Law Checklist must be cleared with the application: lots in a conservation-authority regulated area (TRCA valleylands/floodplains in Markham) need CA sign-off, and Markham's four heritage conservation districts (Thornhill, Markham Village, Buttonville, Unionville) require a Heritage Permit for new construction before building permit issuance
• Garden-suite zoning standards (size, height, rear-yard placement, street-access route) come from Comprehensive Zoning By-law 2024-19 and are lot-specific — the optional $315 Zoning Preliminary Review is the low-risk way to confirm them before paying full permit fees
• Markham's ARU framework is actively changing: Council endorsed allowing up to 3 additional residential units (4 units total) on most low-rise residential lots, with amendments running through late 2025 — and ARUs are excluded in some environmentally sensitive areas, so check the current status for your address
• Fees are estimated at application and must be paid in full before plans review begins; examiners verify the fee during review and any balance owing must be paid before the permit is issued

Fees and timelines are estimates from Markham's published schedules, verified July 9, 2026. Rates and processes change — always confirm current requirements with the building department before you apply.