The 2024 Ontario Building Code (OBC) introduces several significant changes aimed at enhancing safety, accessibility, and harmonization with the National Building Code of Canada (NBC). Key updates include: Download Volume 1 here and Volume 2 here

1. Farm Buildings

• New Classification: Introduction of Group G, Divisions 1 to 4, categorizing farm buildings based on size and occupancy.
• Location in Code: Provisions for farm buildings are now detailed in Part 2 of the OBC.

2. Secondary Suites

• Design Flexibility: Removal of the "house" definition and allowance for lower ceiling heights to facilitate the creation of secondary suites.
• HVAC Requirements: Purpose-built two-unit buildings must have separate return air systems; however, existing buildings undergoing conversion can share a furnace for up to four units under Part 11.

3. Accessibility Enhancements

• Barrier-Free Entrances: All pedestrian entrances to buildings are required to be barrier-free.
• Signage: Expanded requirements for signs, including braille, tactile characters, and symbols of access for hearing loss, to indicate locations of accessible features like entrances, ramps, and parking spaces.

4. Fire Safety Measures

• Standpipe Systems: Standpipe connections are now required to be located within exits.
• Fire Alarms: Buildings equipped with sprinkler systems must also have fire alarm systems installed.
• Sprinkler Coverage: Sprinklers are mandated on all storeys below other storeys that are required to be sprinklered, addressing superimposed major occupancies.

5. Structural Design Updates

• Earthquake Design: Adoption of updated earthquake design provisions to align with the NBC.
• Solar Panels: Introduction of provisions to calculate wind and snow loads for roofs equipped with solar panels.
• Serviceability: Relocation of serviceability information from the "Structural Commentaries - User’s Guide" directly into the Code for easier reference.

6. Plumbing System Revisions

• Terminology Alignment: Updates to code terminology to align with current construction practices.
• Temperature Controls: Implementation of stricter temperature control measures, such as reducing maximum hot water temperatures from 49°C to 43°C in health care and senior resident facilities.

7. Heating and Ventilation Changes

• Code Relocation: Certain HVAC requirements have been relocated to other parts of the Code for better organization.
• Ventilation Standards: Harmonization with NBC standards, including the removal of ventilation Types I to IV classifications.

8. Administrative Modifications

• Professional Oversight: General review by a Professional Engineer is now required for all underpinning projects.
• Demolition Permits: Clarification that demolition permits are not required for farm buildings on farmland, though they remain necessary for farmhouses.

9. Energy Efficiency

• Status Quo: Energy efficiency requirements for houses and large buildings remain unchanged; Supplementary Standards SB-10 and SB-12 continue to apply.
• 
  

Implementation Timeline

• Effective Date: The new 2024 OBC comes into effect on January 1, 2025.
• Transition Period: A three-month grace period is provided until March 31, 2025, for designs substantially completed by December 31, 2024.



These changes reflect Ontario's commitment to modernizing building standards, enhancing safety, and improving accessibility across the province.