2024 Ontario Building Code Updates

The 2024 Ontario Building Code (OBC) came into effect on January 1st, 2025 - the largest ever change in the OBC with +1,700 items being revised. The HCRA continues to supporting your educational needs as you prepare to adapt to these new requirements.

Licensees are encouraged to bookmark this page, to access up-to-date information on the 2024 OBC.

If you haven't already signed up for Ontario's Ministry of Municipal Affairs and Housing's CodeNews, we encourage you to here Building Code updates | ontario.ca. You may also request your free digital copy of the 2024 Building Code Compendium. The 2024 Ontario Building Code | ontario.ca

You can watch the MMAH webinars by going to the following link, answering the questions, and then accessing the dropbox files which contain webinars for each section of the updated code:

MMAH Webinars for the new 2024 Building Code

What you Need to Know about the Transition Timelines:

Please take careful note of the following dates in the transition timeline:

  • April 10, 2024: Release and filing of the 2024 Ontario Building Code.
  • January 1, 2025: 2024 Ontario Building Code in effect.
  • March 31, 2025: Deadline for permit applications using the 2012 Ontario Building Code, where working drawings were substantially complete before January 1, 2025.
  • April 1, 2025: All permit applications must use the 2024 Ontario Building Code.

Key Areas of Focus for the Ontario Building Code:

  1. Radon Mitigation: New houses in Ontario will require a rough-in for a subfloor depressurization system to address soil gas/radon.

    New Homes – C-NRPP

  2. Mass Timber: Updates (article 3.1.6.3) allow new occupancies to use mass timber and specify the range of heights (up to 18 storeys) for fully exposed timber, except in exits and public corridors.
  3. Secondary Suites and Multiplex Conversions: Ontario has aligned with the National Building Code (NBC) for secondary suites but will maintain flexibility on suite sizes to support housing objectives and minimize costs. Information on requirements such as ceiling heights, fire separation, and shared air systems can be found on this webpage.
  4. HVAC: The Heat, Refrigeration and Air conditioning institute (HRAI) has issues resources for the changes in the OBC relevant to HVAC. Click here to view.
  5. Large Buildings (Accessibility)
    1. Harmonize w/ NBC requirements to enhance current OBC requirements,
    2. All pedestrian entrances to be barrier free accessible.
  6. Applicable Law Changes: Updates to the Environmental Assessment Act and Conservation Authorities Act:
    1. Environmental Assessment Act
    2. Conservation Authorities Act
  7. Seismic design requirements: Updates to the Importance Category and Seismic Restraint matrices and terminology (e.g. seismic hazard index is replaced by seismic category). Find more information on this topic from the OAA here.

What did NOT make the 2024 OBC changes:

  1. Home-type care – Group B, Division 4 occupancies
  2. Guard changes, including climbability – MMAH plans to prepare a guide on guards for the industry
  3. Energy efficiency for houses and Large Buildings (did not adopt the NBC approach at this time), i.e. SB-10 and SB-12 will remain at this time
  4. Tornado resiliency of houses (Ottawa & Barrie submissions post tornado)
  5. Septic systems, chamber systems and new leaching bed type.

Additional Resources:

  1. Useful resources from Municipalities. Please note, that these have been generously shared by individual municipalities – the HCRA encourages you to check with your own local municipality on how they plan to interpret the new Code revisions, before starting any planning and permitting:
    • Perth County municipalities: Presentation overviewing the 2024 OBC Changes.
    • City of Markham: Contains details on OBC changes and timing/transition specifics, please click here
    • Municipality of West Grey Overview of Part 9 OBC changes, including secondary suites, HVAC, and structural and guard requirements Part 9 OBC Changes Overview
    • Clearview: Overview of changes to the OBC
    • The City of Kitchener: 2 sessions with an overview of changes to various aspects of the OBC PowerPoint Presentation
  2. NBC 2020 Illustrated Guides: The Canadian Board for Harmonized Construction Codes (CBHCC) has released complimentary illustrated resources for Housing and Small Buildings within the National Building Code (not all of the information will be applicable to the 2024 Ontario Building Code). These resources are accessible here
  3. 2019 Building Code Amendments related to Stairs, Guards and Handrails: Reminder that amendments related to stairs, guards and handrails came into effect on January 1, 2022. They were part of 2019 changes to the Building Code to further harmonize Ontario's Building Code with the 2015 National Codes.