2024 code changes

Secondary Suites in the 2024 Ontario Building Code: What Changed

The 2024 Ontario Building Code makes 'secondary suite' a defined term and deletes the old defined term 'house', changing how Part 9 addresses dwellings with additional units. For BCIN candidates this matters because exam questions now use the new terminology and article numbers. Answers keyed to 2012-era wording point you to the wrong place.

What is a secondary suite under the 2024 code?

'Secondary suite' became a defined term in the 2024 Ontario Building Code. In everyday language the concept is an additional self-contained dwelling unit (the classic basement apartment), but the everyday gloss is not what a plans examiner or an exam question works from. The defined term has precise wording, and that wording controls how the code applies to a project. Read the definition itself in Division A of the 2024 Building Code Compendium rather than trusting any paraphrase, including ours. Those two volumes are the ones you're allowed to bring into the open-book BCIN exams anyway.

The new term is one of roughly 1,730 amendments separating the 2012 and 2024 codes, documented in the Ministry of Municipal Affairs and Housing's 118-page Key Changes bulletin. For the full picture of the revision, start with our pillar guide to all 1,730 amendments.

Why does deleting 'house' matter?

The same revision that added 'secondary suite' deleted 'house' as a defined term. That sounds like housekeeping. It isn't: it changes how you find things.

Every practitioner who trained on the 2012 code carries search habits built around 'house': it's the term you scanned for in the index, the word you typed into the PDF search box, the hook your mental map of Part 9 hung on. In the 2024 Building Code Compendium that hook is gone. Provisions were reworded and reorganized around the current terminology, so a keyword search for 'house' no longer surfaces the provisions you actually need. On a timed, open-book exam, that costs minutes you don't have.

The fix is mechanical: retrain your search vocabulary on 2024 terms ('secondary suite' among them) and confirm each defined term in Division A before you rely on it.

Where do the secondary suite requirements live now?

Part 9 was reorganized and mass-renumbered in the 2024 code, so we won't hand you a tidy list of article numbers from memory, because 2012-era references frequently point at the wrong provision now. One verified example of the shift: former article 9.8.4.4A is now 9.8.4.5. Our renumbering map covers the old-to-new moves that trip people up most.

For suite work specifically, the reliable route is: locate the defined term in Division A, then follow the Compendium's own index and cross-references to the current Part 9 provisions. To see what moved and why, the primary source is MMAH's 2024 Building Code Technical Bulletins: Highlights of Key Changes (July 2024, PDF), 118 pages mapping the amendments. Where a summary and the code text disagree, the Compendium wins.

Which related 2024 changes hit suite work?

Several verified 2024 changes land squarely in the kind of Part 9 work suite projects involve:

• Smoke barrier: 9.10.9.16.(4) specifies a 15.9 mm Type X smoke barrier in its context. Read the full article for scope. This is a spot where quoting half a sentence gets designers into trouble.
• Stairs: open risers are banned under the new article 9.8.4.9, a provision with no 2012 equivalent.
• Guards: the 150 mm sphere rule sits at 9.8.8.5.(2).
• Framing: spacings went hard-metric: 305/406/610 mm became 300/400/600 mm.

None of these appear in 2012-era study material, and all of them are exactly the sort of lookup an exam question can force you to perform against the clock.

How do the BCIN exams test the new terminology?

Since March 30, 2026, all BCIN qualification exams are based on the 2024 Building Code. The format is the same across all 16 exams: 70 multiple-choice questions, 3 hours, open book, 70% to pass, $150 per attempt through Humber Polytechnic. The permitted material is the 2024 Building Code Compendium, Volumes 1 and 2, in hard copy and/or PDF.

We won't claim to know which questions appear on live exams. Nobody selling prep can honestly claim that. What we can verify is the basis: the exams test the 2024 code, and the 2024 code uses 'secondary suite', not 'house', with renumbered Part 9 articles. In an open-book format where you have about two and a half minutes per question, candidates who search on dead terminology lose time on every dwelling-related question. If the House exam is on your list, our BCIN House exam guide walks through the syllabus and the 2024 changes most likely to catch you out.

Do homeowners need a BCIN for a suite project?

This page draws two audiences, so let's separate them. If you're a homeowner planning a basement suite, the Building Code still governs your project, but whether you personally need a BCIN depends on who takes design responsibility for the drawings. Ontario's rules on who must be registered are set out on ontario.ca's building-practitioner pages, and your municipality's building department can tell you what your permit application needs. Most homeowners hire a qualified designer rather than qualify themselves.

If you're the designer taking on suite work, or planning to be, the BCIN qualification exams are the gate, and the House exam is the usual technical exam for this category of work. That path starts with understanding the 2024 code, because that's the edition the exams now test.

FAQ

Sources: MMAH 2024 Building Code Technical Bulletins: Highlights of Key Changes (July 2024); 2024 Building Code Compendium (Publications Ontario); Humber Polytechnic candidate protocol and exam-format pages; ontario.ca practitioner and study-guide pages. Last reviewed 2026-08-14. Found an error? Tell us and we'll fix it.