2024 code changes: reference

2024 Ontario Building Code Renumbering Map: Old Article Numbers vs New

The 2024 Ontario Building Code renumbered large blocks of articles, so 2012-era references no longer land where you expect. For example, 9.8.4.4A is now 9.8.4.5. Because BCIN exams are open book and scored on how fast you can navigate the new numbering, this page maps the old-to-new article numbers that changed most.

Why did the 2024 code renumber so many articles?

Harmonization. The 2024 Ontario Building Code adopts the 2020 National Building Code of Canada with Ontario amendments, and its numbering deliberately aligns with the 2020 NBC/NPC. Where Ontario keeps a provision the national code doesn't have, the 2024 code marks it with a letter-suffixed number (9.10.14.3A, 9.31.4.1A), so national numbering stays intact around it. The result: dozens of Part 9 articles moved, some numbers were reused for different provisions, and several 2012 Ontario-only articles disappeared entirely. The full story of the changeover is in what changed in the 2024 Ontario Building Code; this page is the lookup reference.

How do you use this map?

Two ways. Studying: when your 2012-era notes, course material, or memory produce an article number, check it here before trusting it. Tabbing: if you're preparing a hard-copy 2024 Compendium for a test centre, tab the new numbers in the right-hand column. Those are the ones exam questions and answer options will use. Then drill lookups under time pressure; our open-book tabbing strategy guide covers the method.

Part 9 renumbering table: which old numbers moved where?

Source: MMAH, 2024 Building Code Technical Bulletins: Highlights of Key Changes (July 2024), Division A and Division B Part 9 bulletins (PDF, 118 pp.). The bulletin is guidance; where it and the 2024 Building Code Compendium disagree, the Compendium governs. This table lists the moves the bulletin states explicitly. It is not exhaustive.

Worked example: what happened to 9.8.4.4A?

The 2012 Ontario-only article 9.8.4.4A, "Uniformity of Runs in Flights with Mixed Treads within a House or Dwelling Unit," was renumbered and renamed as 9.8.4.5, "Uniformity of Runs in Flights with Mixed Treads within Dwelling Units." That one move set off a chain: Winders slid from 9.8.4.5 to 9.8.4.6, spiral stairs from 9.8.4.5A to 9.8.4.7, and leading edges of treads from 9.8.4.6 to 9.8.4.8 (now "Tread Nosings"). A brand-new 9.8.4.9 was inserted, and interior stairs extending through a roof landed at 9.8.4.10. One renumbering rarely travels alone. Assume the whole subsection shifted.

Which articles are new, with no 2012 equivalent?

• Division B, Part 2: farm buildings. Previously reserved, now an entire Part with the new Group G agricultural occupancy classification.
• 9.8.4.9. Open Risers. Prohibits open stair risers in Part 9 buildings, with limited exceptions, consistent with Part 3.
• Sentence 9.8.8.5.(2). The 150 mm sphere rule for triangular openings at stair guards (except industrial occupancies).
• Sentence 9.8.2.2.(4). Permits 1 850 mm clear height over stairs under beams and ducts in secondary suites.
• 9.23.2.4. Connections to Preservative-Treated Wood. Fastener material requirements; it displaced Lumber to 9.23.2.5.
• Subsection 9.23.13. Bracing to Resist Lateral Loads Due to Wind and Earthquake. Braced wall panels; it pushed subsections 9.23.13 through 9.23.16 up by one.
• Subsection 9.27.13. Polypropylene Siding. Displaced exterior insulation finish systems to 9.27.14.
• 9.31.6.1. Hot Water Supply. Displaced the Ontario-only hot water temperature article to 9.31.6.1A.

Deletions matter too: the 2012 articles 9.1.1.12 (houses above houses) and the Ontario-only 9.23.2.5 (termite protection, now handled under 9.3.2.9) are gone.

Where do renumbering traps bite on the open-book exams?

The dangerous cases aren't the numbers that vanished. They're the numbers that still exist but mean something else. In the 2024 code, 9.8.4.5 is uniformity of runs, not Winders. 9.10.1.1 is sloped roofs, not support of noncombustible construction. 9.21.1.2 is chimney walls, not factory-built chimneys. Under exam time pressure, a lookup that "works" feels verified even when it lands on the wrong provision. Second trap: block shifts. Everything from old 9.10.9.8 onward moved down two, so an answer option quoting 9.10.9.14 is testing whether you know that's now residential suites and live/work units, not separation of residential suites. Third: new articles like 9.8.4.9 simply don't exist in old cross-reference sheets, so 2012-era materials return a confident blank. Writing the House exam? The House exam guide covers which of these areas its syllabus hits hardest.

FAQ

Sources: MMAH 2024 Building Code Technical Bulletins: Highlights of Key Changes (July 2024); Humber Polytechnic Candidate Protocol (rev. 2026-03-31); ontario.ca 2024 Building Code study-guide pages. Last reviewed 2026-08-14. Found an error? Tell us and we'll fix it.