Markham Secondary Suites Guide for Homeowners
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:
- You must obtain a building permit before adding a secondary suite to your home.
- 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.
- 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:
- Application Forms
- Documents
- Construction drawings
- 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.