2024 Ontario Building Code Changes
What homeowners, contractors, and designers need to know about the new building code requirements in Ontario.
✅ The 2024 Ontario Building Code is now fully in effect. All permit applications must comply.
What You Need to Know
The 2024 Ontario Building Code (O. Reg. 31/24) came into effect on January 1, 2025, replacing the 2012 Building Code. This is the first major update to the OBC in over a decade.
As of April 1, 2025, the transition period has ended. All building permit applications must now comply with the 2024 OBC requirements.
For ongoing projects: If your permit was issued under the 2012 OBC, you can continue construction under those requirements. The 2024 OBC applies to new permit applications submitted after April 1, 2025.
Implementation Timeline
Last day to submit applications under the 2012 Ontario Building Code.
2024 Ontario Building Code comes into force. Transition period begins.
Applications could be submitted under either 2012 or 2024 OBC if designs were substantially complete by Dec 31, 2024.
All new building permit applications must comply with the 2024 OBC. No more applications accepted under 2012 code.
We are here. All applications must use 2024 OBC. Transition period has ended.
Key Changes by Category
Accessibility
Barrier-Free Path of Travel
Enhanced requirements for accessible routes in multi-unit residential buildings, including wider corridors and improved door clearances.
Accessible Parking
Updated standards for accessible parking spaces with clearer signage and path requirements.
Washroom Accessibility
New specifications for grab bars, fixture heights, and maneuvering space in accessible washrooms.
Energy Efficiency
Higher Insulation Values
Increased R-value requirements for walls, ceilings, and foundations to improve energy performance.
Air Sealing Standards
Stricter air barrier continuity requirements to reduce energy loss and improve building envelope performance.
EnerGuide Compliance
New provisions for energy performance modeling and reporting requirements.
Radon Protection
Mandatory Radon Mitigation
New buildings now require radon mitigation rough-ins, including sub-slab depressurization systems or equivalent protection.
Soil Gas Barriers
Enhanced requirements for soil gas barriers in foundation construction to prevent radon infiltration.
Radon-Ready Construction
Provisions for easy future installation of active radon mitigation systems if needed.
Fire Protection
Sprinkler Requirements
Expanded sprinkler requirements for certain building types and configurations.
Fire Separation Updates
Revised fire separation requirements between units and between residential and non-residential uses.
Smoke Alarm Standards
Updated smoke and carbon monoxide alarm requirements, including interconnection standards.
Structural
Mass Timber Buildings
New provisions allowing Encapsulated Mass Timber Construction (EMTC) for buildings up to 18 storeys.
Snow Load Updates
Revised snow load calculations for certain regions based on updated climate data.
Seismic Requirements
Updated seismic design requirements for buildings in specific zones.
HVAC & Mechanical
Ventilation Standards
Updated mechanical ventilation requirements for improved indoor air quality.
Heat Recovery
Enhanced requirements for heat recovery ventilators (HRVs) in new construction.
Duct Sealing
Stricter duct sealing requirements to improve HVAC efficiency.
How This Affects Your Project
🏠 Decks & Porches
Most deck requirements remain similar to the 2012 code. Key updates include guard height specifications and structural connection details. If your deck connects to the house, ensure your designer references the 2024 OBC for ledger board connections.
🏗️ Basement Renovations
Radon protection is now required for basement renovations that involve new concrete work. Fire separation requirements between basement apartments and main dwellings have been updated. Egress window requirements remain in place.
🏡 Additions
Room additions must meet enhanced energy efficiency requirements, including higher insulation values. If your addition includes a new furnace or HVAC system, updated ventilation standards apply. Expect more detailed energy compliance documentation.
🏢 New Construction
New homes face the most significant changes: mandatory radon protection, enhanced energy efficiency standards, improved accessibility requirements for multi-unit buildings, and updated fire safety measures. Budget for additional compliance costs.
For BCIN Designers & Contractors
Training: Ensure your 2024 OBC training is up to date. Many professional associations offered transition training in late 2024 and early 2025.
Drawing Templates: Update your drawing templates and standard details to reflect 2024 OBC requirements, particularly for:
- Radon mitigation rough-in details
- Updated guard and handrail specifications
- Energy compliance documentation
- Revised fire separation details
Fees: Some projects may require additional documentation under the 2024 OBC. Consider adjusting your fee structure accordingly.
Official Resources
Related Resources
Submitting Under the New Code?
Our pre-check tool helps ensure your permit package is complete before you submit. Catch common issues and save time.
Run Free Pre-CheckThis guide provides a general overview of 2024 OBC changes as of December 2025. For specific requirements, consult the official Ontario Building Code or a qualified building professional.