Ontario announced a new 2024 Ontario Building Code (OBC). The changes prioritize public safety, housing affordability, sustainability, and climate resilience while streamlining processes for builders and municipalities. The new Building Code aligns with the National Building Code while retaining provisions specific to Ontario’s needs, ensuring consistency across the province. The 2024 OBC will be effective January 1, 2025.

Timing and transition provisions

The 2024 Building Code comes into effect on January 1, 2025, with a three-month grace period until March 31, 2025 for certain designs that are already underway.

Please take careful note of the following transition period dates:

Until December 31, 2024

  • Permit applications must be submitted using the 2012 Building Code

January 1, 2025 to March 31, 2025

  • Permit applications may be submitted using the new 2024 Building Code
  • Permit applications may be submitted using the 2012 Building Code if the applicant demonstrates that their working drawings were substantially complete by December 31, 2024

April 1, 2025

  • Permit applications must be submitted using the 2024 Building Code

2024 Ontario Building Code Change Highlights

The list below includes highlights and new requirements that may be applicable to local projects. Please note that this list is not the complete or final list of code changes. 

Please visit the Province of Ontario's website for more information on the 2024 Ontario Building Code. 

Farm Buildings
  • Harmonizing with NBC and located in a new section of the OBC - Part 2.
  • Farm building requirements will be divided into small and large buildings.
  • New occupancy classification - Group G, Division 1 to 4.

 
 Houses
  • New requirements for guards around windows.
  • Increased restrictions on opening sizes for stair guards.
  • Expanded requirements for carbon monoxide alarms.
  • New minimum separation distance requirements for exhaust outlets.
  • Minimum sump pit sizes.

Two Unit Houses / Secondary Suites 
  • Smoke tight barriers replace traditional fire separations.
  • Mandatory installation of interconnected smoke alarms.
  • Increased requirements for carbon monoxide alarms.
  • Lower ceiling heights and shared egress options.
  • Prohibited sharing of return air on purpose built 2-unit buildings (conversions of existing buildings can still share furnace for up to 4 units under Part 11). 
 Large Buildings (Fire Safety)
  • Harmonization of fire protection with NBC (standpipe, fire alarm systems, sprinklers).
  • Standpipe connections are to be located in exits.
  • If sprinklers are installed, a fire alarm system is required.
  • Sprinklers are required on all storeys below other storeys that are required to be sprinklered.
  • Mezzanine and interconnected floor space requirements (changes to exit, egress, fire compartments, smoke control, travel distance, and more.)
Septic Systems (Ontario-only changes) 
  • Increased safety requirements for septic tanks, treatment units and holding tanks. 

Structural Design
Harmonization with the National Building Code in the following areas,
  • Earthquake design
  • Importance categories – revises the descriptions.
  • Solar panels – introduces provisions to calculate wind and snow loads for roofs.
  • Canopies and parapets – new provisions to calculate wind loads for attached canopies, roof parapets, and balcony guards at top of buildings.

 

Accessibility 
  • All pedestrian entrances are to be barrier free accessible.
  • Service counters and water bottle filling stations in new commercial and public buildings must be accessible. 
 Carbon Monoxide
  • Current requirements have been enhanced by expanding residential requirements and adding care occupancy and some commercial establishment requirements.

 
 Radon
  • Harmonized with the NBC, including mandatory rough-in for a sub floor depressurization in all new homes.
  • SB-9 revised, and new Appendix note (with examples of rough-in pipe to be provided)

 
Plumbing 
  • Greater flexibility and more choices were provided (e.g. alternative temp. limiting devices, new plumbing materials).
  • Improved health and safety requirements (i.e. max. temp. from 49°C to 43°C in health care and senior resident facilities).
  • Clarification of technical requirements such as, shower heads, domestic water tanks, and grease interceptors.
  • Standardization of non-potable water systems for rainwater harvesting and greywater reuse.

 

Heating and Ventilation 
  • Subsection 6.2.4 has been moved to Section 9.33.,
  • Section 9.32. was harmonized with NBC, including removal of ventilation Types I to IV.
  • Commercial kitchen hood fire protection requirements in Part 6 have been moved to Part 3.
  • Ventilation of storage and repair garages was harmonized, except carbon monoxide in repair garage.

 

Division A and C (Administrative Changes)
  • General Review by a Professional Engineer required for all underpinning.
  • Clarification, demolition permit is not required for the farm buildings on farmland. Still required for the farm-house building.