The Ontario Building Code (OBC) received one of its most significant updates in years with the 2024 edition, continuing the province's push to increase housing supply while modernizing accessibility and energy requirements. If you are planning a build, an addition, or a second unit, these changes affect how your drawings are prepared and reviewed. Here is a plain-English breakdown of what changed and what it means for your permit.
When the 2024 Code Takes Effect
The 2024 Ontario Building Code came into force on January 1, 2025, with a three-month transition period. Applications could still be submitted under the legacy 2012 code until March 31, 2025, provided the working drawings were substantially complete before the new year. Since that window has closed, every new permit application is now reviewed against the 2024 Code, so your drawings must reflect the current requirements to avoid a rejection or deficiency notice.
Housing Supply: Multiplexes and Second Units
The biggest theme of the update is gentle density. Combined with provincial housing legislation, the framework now supports:
- Multiplexes up to four units as-of-right on most residential lots province-wide, without a rezoning
- Additional residential units (a second and often a third unit) permitted in most residential zones, including basement apartments and garden suites
- Reduced parking requirements - many municipalities can no longer require additional parking for second units
For homeowners, this means adding a rental unit or converting to a multiplex is more feasible than ever - though each unit still needs a building permit, code-compliant fire separation, egress, and (in most cities) registration.
Barrier-Free & Accessibility Updates
The 2024 Code strengthened barrier-free requirements, which matter most for commercial and multi-unit projects. Notable changes include increased ramp widths (minimum 1000 mm), larger level landings of 1700 mm by 1700 mm at the top and bottom of ramps, and power door operators at barrier-free entrances. If your project is a commercial fit-out or a larger building, these details need to be shown correctly on your drawings.
Energy Efficiency (SB-12)
Energy compliance requirements under SB-12 continue to tighten for new construction and additions - insulation values, window performance, and air-tightness all factor into approval. Our drawings include the required energy compliance documentation so this does not hold up your permit.
What This Means for Your Permit
The practical takeaway: any set of drawings submitted today must be prepared to the 2024 Code. Older templates and drawings that were "substantially complete" before 2025 no longer qualify for the legacy code. At Ontario Design Studio, every drawing set we prepare is updated to the current OBC, which is one of the main reasons our submissions clear plan review without avoidable back-and-forth. If you have an older set prepared by someone else, we can review it and bring it up to the 2024 standard.
Ready to get started?
Call 416-558-9607 for a free consultation or request a quote online. Every drawing set we prepare is built to the current 2024 Ontario Building Code.