If you studied for a BCIN exam a few years ago, the code you learned is not the code you will be tested on today. The 2024 Ontario Building Code changes are a major update, with more than 1,730 amendments according to the Ministry of Municipal Affairs and Housing. The structure of the book changed, a new Part was added, and many familiar Part 9 requirements were adjusted.

This guide covers when the 2024 OBC took effect, how the transition worked, the main categories of change and, most importantly for you, what it all means for your exam prep.

When the 2024 Ontario Building Code Took Effect

The 2024 Building Code is Ontario Regulation 163/24, filed in April 2024 under the Building Code Act, 1992. It replaced the 2012 Building Code (O. Reg. 332/12). Here is the timeline published by the province:

• April 10, 2024: The new code was released, giving the industry several months to prepare.
• January 1, 2025: The 2024 OBC came into force.
• January 1 to March 31, 2025: A three month transition period. Permit applications could still be reviewed under the 2012 code if the working drawings were substantially complete before January 1, 2025.
• April 1, 2025 onward: All permit applications are reviewed under the 2024 OBC.

The transition window is closed. Any new design or permit application today falls under the 2024 code, so that is the edition you need to know.

The Big Picture: Harmonization With the National Building Code

The headline goal of the 2024 code was harmonization. The province says the update eliminates at least 1,730 technical variations between Ontario’s requirements and the national model codes. The idea is that builders, designers and manufacturers working across provinces deal with fewer Ontario-only rules, which the government has tied to its broader push to build more homes.

A new structure for the code itself

This is the change that catches most people off guard. The 2024 OBC is no longer one self-contained regulation that reprints every requirement. Instead, it adopts the 2020 National Building Code of Canada (NBC) by reference, with Ontario’s differences published in a separate Ontario Amendment Document. The regulation on e-Laws is short; the technical content lives in the NBC plus the amendments.

In practice, most people work from a consolidated version (such as the Building Code Compendium) that merges the two. That is also what you want for exam prep, since flipping between two separate documents under time pressure is a recipe for lost minutes. The Ontario Amendment Document has also been updated since release (for example, O. Reg. 5/25 in January 2025 updated it to the version dated January 13, 2025), so make sure your copy is current.

A new Part 2 for farm buildings

Division B now includes a new Part 2 dealing with farm buildings, including provisions for large farm buildings. Exam candidates should know that this Part exists and that the old Part numbering you may remember has shifted around it. The Ministry and OBOA both highlight Parts 3, 7 and 9 as areas with significant revisions.

Notable Technical Changes in the 2024 OBC

With 1,730+ amendments, no single article can cover everything. Below are the changes highlighted by the province, the Ontario Building Officials Association (OBOA), the Ontario Home Builders’ Association (OHBA) and municipal building departments. Always confirm exact wording in the code itself.

Encapsulated mass timber up to 18 storeys

Through O. Reg. 447/24 (effective January 1, 2025), the province expanded encapsulated mass timber construction from 12 storeys to 18 storeys. The amendment also broadened the occupancies where mass timber can be the primary structural material and relaxed some encapsulation requirements to encourage innovation in wood construction.

Secondary suites and two-unit houses

Ontario’s two-unit house provisions were harmonized with the NBC requirements for secondary suites. Ontario kept its own flexibility on minimum suite size to support housing goals. Related changes highlighted by municipalities and OHBA include:

• Smoke alarms within a secondary suite may be interconnected wirelessly (Div. B, 9.10.19.5).
• OHBA notes that secondary suites now require separate HVAC systems for each unit.

Radon and soil gas

Soil gas requirements were harmonized with the NBC. New houses must include a rough-in for a subfloor depressurization system, so one can be completed later if needed. This is a good example of a change that shows up on House and Small Buildings exams, since it affects every new home.

Other Part 9 changes worth knowing

Municipal building departments have published handouts summarizing Part 9 changes. Items commonly highlighted include:

• Drift loading: new provisions for snow drift between roof levels where the upper roof area exceeds 600 m² (9.4.2.2).
• Open risers: now limited to specific situations, such as stairs within a single dwelling unit (9.8.4.9).
• Low window sills: where a sill is less than 900 mm above the floor, the window needs a guard or a device that limits the opening (9.8.8.1).
• Sump pits: larger minimum size, at least 750 mm deep and 0.25 m² in area (9.14.5.2).
• Foundation insulation: insulation now required for the full height of basement walls (9.25.2.3).
• Carbon monoxide alarms: required in bedrooms where a wall, floor or ceiling abuts an attached garage (9.32.3.9A).
• Treated wood fasteners and veneer ties: updated corrosion protection and tie requirements (9.23.2.4 and 9.20.9.5).

Structural, fire protection and accessibility

• Structural: revised importance categories, a web-based seismic data tool, and new provisions for wind and snow loads on roofs with roof-mounted solar panels.
• Fire protection: standpipe, fire alarm and sprinkler requirements were harmonized with the NBC.
• Accessibility: accessibility requirements for larger buildings were updated to align more closely with the 2020 NBC.
• Sewage systems: updated standards for prefabricated septic and sewage tanks, including safety screens below cleanout covers.

What did not change: energy efficiency

Energy is where some people expected a big shift. It did not happen. According to OHBA’s summary, Ontario did not adopt the national tiered energy performance approach, and Supplementary Standards SB-10 and SB-12 remain in place. If you studied SB-12 compliance packages before, that knowledge still applies.

Want a structured way to learn the new code instead of piecing it together from bulletins? Browse our BCIN exam prep courses, all built on the 2024 OBC.

How the 2024 Code Affects Your BCIN Exam

Exams are now based on the 2024 OBC

The building code exams did not switch on January 1, 2025. They lagged behind the code itself. According to ontario.ca and OBOA:

• March 8, 2026 was the last day to book a 2012 code exam.
• March 15, 2026 was the last day 2012 exams were administered.
• No exams were offered from March 16 to 29, 2026.
• Since March 30, 2026, all Ontario building code exams are based on the 2024 Building Code.

So if you are writing any BCIN exam today, whether that is General Legal/Process, House, Small Buildings or a specialty exam, you are being tested on the 2024 code. Old practice questions built on the 2012 code can actively hurt you, because section numbers, Part numbering and some requirements have changed.

Use the 2024 study guides

The Ministry publishes study guides (syllabi) for each 2024 exam on ontario.ca. They list which Parts and sections are in scope for each exam. Download the one for your exam before you start studying, and treat any 2012 syllabus as archived material only.

Relearn your navigation

BCIN exams are open book, so your speed at finding the right clause matters as much as what you remember. If you tabbed a 2012 code book, those tabs are now pointing at the wrong places. Start fresh: tab the 2024 Parts you will use most, learn where Part 2 sits, and get used to how the NBC numbering and Ontario amendments appear in your consolidated copy.

Focus on the high-frequency changes

For House and Small Buildings candidates, Part 9 changes like radon rough-ins, secondary suites, guards and windows, CO alarms and sump pits are exactly the kind of practical, everyday items exam writers like to test. For Large and Complex Buildings candidates, pay attention to Part 3 fire protection harmonization, accessibility and mass timber.

Getting the Right Code Book

The single most important thing you can do is study from the correct edition. A 2012 code book is no longer useful for the exam or for permit work. We walk through your options for getting a copy of the current code in our post on how to get the 2024 Ontario Building Code PDF.

Before exam day, confirm with Humber Polytechnic (which delivers the exams) exactly which reference materials are permitted, since that is the version you should practise with.

Frequently Asked Questions

When did the 2024 Ontario Building Code come into effect?

The 2024 OBC (O. Reg. 163/24) came into effect on January 1, 2025. A transition period allowed some permit applications to use the 2012 code until March 31, 2025, if working drawings were substantially complete before January 1, 2025. From April 1, 2025, all applications fall under the 2024 code.

Are BCIN exams based on the 2024 or 2012 code?

All Ontario building code exams have been based on the 2024 Building Code since March 30, 2026. The last 2012 code exams were administered on March 15, 2026.

Is the 2024 OBC the same as the National Building Code?

Not exactly. The 2024 OBC adopts the 2020 National Building Code of Canada and then modifies it through the Ontario Amendment Document. Many requirements now match the NBC, but Ontario-specific rules still exist, including the continued use of SB-12 for energy efficiency.

Can I still use my old 2012 practice questions?

Use them with caution, if at all. Section references, Part numbering and some technical requirements have changed, so a question that was correct under the 2012 code may now have a different answer. Practise with material written for the 2024 OBC.

Start Studying the Right Code

The 2024 Ontario Building Code changes are big, but they are manageable when you study from the right book with the right questions. Our courses are built on the 2024 OBC, with practice questions that train you to find answers fast. Start with the General Legal/Process exam prep course, which almost every BCIN candidate needs, or pair it with the House exam prep course if you design or inspect homes.