: New requirements for rough-ins for sub-floor depressurization in all new homes. Carbon Monoxide
: Enhanced standards for early detection, warning systems, and fire-resistance ratings for large buildings. Municipality of Trent Lakes 2024 Ontario Building Code Updates - City of Kingston
aimed at reducing red tape for the construction industry while maintaining high safety standards. ontario.ca Key Feature: National Harmonization
To combat the housing crisis, the 2024 code introduces flexible design options for multi-unit residential buildings.
If your permit lapses or you request a major revision after 2024, the building official can require full compliance with the new code.
The OBC 2024 is actually more permissive for density (ADUs) and safety (backwater valves), but it is stricter on physics (energy/airtightness).
OBC 2024 retains the 9-division structure but introduces significant reorganization:
One of the most consequential changes for new home construction is the mandatory radon rough-in. to address soil gas and radon.
Historically, Ontario maintained a highly customized building code tailored strictly to provincial precedents. While effective, this created regulatory fragmentation across Canada, making it difficult for manufacturers, developers, and skilled trades to operate seamlessly across provincial borders.
Starting March 30, 2026 , all Building Code exams will be based on the 2024 edition. Key Technical Changes for Housing (Part 9)
Introduction The Ontario Building Code sets minimum standards for the design and construction of buildings in Ontario, aiming to protect public health and safety, accessibility, fire protection, and energy efficiency. The 2024 edition reflects evolving priorities: lower-carbon buildings, improved resilience to climate impacts, enhanced life-safety measures, and clearer pathways for modern construction methods and technologies.
: Could still use the 2012 OBC if plans were substantially completed by December 31, 2024. City of Kingston Major Technical Changes
A standout feature of the 2024 Ontario Building Code (OBC) is its extensive harmonization with the National Building Code of Canada Effective as of January 1, 2025 , this update includes over 1,700 technical changes