What Is a Secondary Suite?

Homeowners create a secondary suite (also called an “accessory suite”, “second suite” or “secondary unit”) as an additional residential dwelling unit within a house.

• A house contains a maximum of two dwelling units, which comprise the main living area and the secondary suite.
• Builders can construct the secondary suite on the same floor, above, or below the main part of the house, and they can design it to span more than one storey.
• Secondary suites can be added to:
  • Detached houses
  • Semi-detached houses
  • Row townhouses

Where to Start

Review Markham’s Guide for Homeowners for detailed requirements to create a dwelling unit/ADU:

1. You must obtain a building permit before adding a secondary suite to your home.
2. Property owners must review the Guide for Homeowners to confirm that their property complies with all applicable requirements, including site, parking, fire separation, HVAC, and other requirements.
3. Use the City of Markham’s Property Details Search tool to find out the zoning applicable to your property. This free service provides the zone designation, official plan designation, by-law number, and applicable law summary.

How to Apply

Building Permit Requirements

You must apply online through the ePLAN Portal to obtain a building permit.

• Submission requirements depend on building location, the type of municipal services on the lot, and if the building is new or being renovated.
• There are four main parts to every building permit application:
  1. Application Forms
  2. Documents
  3. Construction drawings
  4. Permit Fees

Find a comprehensive list of the required drawings, documents, and forms here.

Building Inspections

• Review the Guide for Homeowners for the list of inspection stages.

Registration

• Register all secondary suites with Markham Fire and Emergency Services. Fire and Emergency Services staff must check the entire home – for a fee – in order to register the building.
• You must provide documentation to Fire and Emergency Services. Review the Guide for Homeowners for the full list.
• Contact Markham Fire & Emergency Services to begin the process:
  • Phone number: 905 415 7521
  • Email: Fire-PreventionChiefs@markham.ca

Review the Guide for Homeowners for more information on how to build a secondary suite.