Part 9 vs Part 3: Which Building Code Path Applies to Your Project in Nova Scotia

Before a parcel becomes a building, two questions decide most of its cost and timeline. The first is what the zoning lets you build. The second — quieter, but just as consequential — is which path through the building code that building takes. In Nova Scotia, every project lands in one of two regimes: Part 9 ("Housing and Small Buildings") or Part 3 of the National Building Code. The boundary between them is not a matter of preference. It is set by storey count, floor area, and occupancy type, and crossing it changes who must stamp the drawings, how long review takes, and what the building costs to deliver.

For anyone weighing what to develop on a serviced lot in Halifax Regional Municipality (HRM) — a fourplex, a small apartment, a stacked townhouse — the Part 9 / Part 3 line often matters more than the unit count itself. This article explains where the line sits under the code now in force, what triggers each path, and why getting the classification right at the feasibility stage is what keeps a project from being redesigned mid-stream.

As of 2026-06-23, the figures below reflect the National Building Code of Canada 2020, adopted in Nova Scotia under N.S. Reg. 198/2024 and in force since April 1, 2025 [1][2].

The code that governs your project changed in 2025

Nova Scotia does not write its own building code from scratch. It adopts the national model codes and amends them. The Nova Scotia Building Code Regulations now adopt the National Building Code of Canada 2020, the National Energy Code of Canada for Buildings 2020, and the National Plumbing Code of Canada 2020 (with revisions issued on or before April 1, 2023), brought into force April 1, 2025 under N.S. Reg. 198/2024 [1][2].

That date matters for two reasons. First, any project whose permit is reviewed under the current rules is being judged against NBC 2020, not the older edition that governed work permitted before April 2025. Second, the province is phasing in the more demanding energy and structural tiers of the 2020 codes on a schedule — building-code Tier 1 and energy-code Tier 1 took effect April 1, 2025; building-code Tier 2 on April 1, 2026; energy-code Tier 2 on April 1, 2027; and further tiers in 2027 and 2029 [2]. For energy performance specifically, the Section 9.36 requirements for houses and small buildings move to at least Tier 2 for climate Zone 6 as of April 1, 2026 [2]. A building's energy envelope, therefore, is a moving target — what was compliant in 2024 is not the standard a project entering design in 2026 is held to.

None of this changes the Part 9 / Part 3 boundary itself. But it does mean the cost of either path has been rising as the tiers ratchet up, which is exactly why the classification deserves attention before a shovel — or a drawing — is committed.

Where the line sits: the Part 9 thresholds

Under the National Building Code as adopted in Nova Scotia, a project qualifies for the simpler Part 9 path only if it meets all three of the following conditions [3]:

1. It is 3 storeys or fewer in building height; and
2. Its building area is not more than 600 m² (about 6,460 sq ft); and
3. It is not an excluded major occupancy — that is, not an assembly building, not a care, treatment or detention occupancy, and not a high-hazard industrial occupancy.

Fail any one of these, and the project becomes a Part 3 building [3]. The three tests are independent: a two-storey building of 700 m² is Part 3 on area alone; a four-storey building of 400 m² is Part 3 on height alone; a small two-storey building with a care facility in it is Part 3 on occupancy alone, regardless of its size.

It is worth being precise about what each threshold measures.

Storeys. Height is counted in storeys above grade. The common shorthand — basement plus ground floor plus two upper floors — captures the typical low-rise, but the controlling test is the code's definition of building height, not the marketing description of the building. A fourth occupied storey above grade pushes the building into Part 3 even if the floor plates are modest.

Building area. The 600 m² limit is a building-area test, not a per-unit or per-suite figure. For most small multi-unit forms on a single serviced lot in HRM, a careful design stays inside it — but wide common corridors, large amenity rooms, or a generous footprint can quietly carry a project over the line.

Occupancy. A standard residential building — apartments, townhouses, the kind of Group C residential occupancy that does not require an architect — is the home turf of Part 9 [3]. Buildings serving vulnerable occupants (care or treatment facilities) and assembly uses are carved out by the code and handled under Part 3 regardless of how small they are [3].

What Part 9 and Part 3 actually demand

The two paths are not just "small" versus "large." They are two different philosophies of compliance.

Part 9 is largely prescriptive. It sets out construction methods, dimensions, and material requirements that, if followed, are deemed to satisfy the code's safety objectives. For a builder and designer working within established residential practice, that is a relatively predictable path: standard details, conventional framing, well-understood approval expectations.

Part 3 is objective- and performance-based for the elements it governs. Rather than handing the designer a recipe, it sets the safety outcomes a building must achieve — in fire protection, structural capacity, means of egress, and accessibility — and leaves the design team to demonstrate they have been met. That demonstration is what requires professional engineers and, frequently, architects: structural, mechanical, and fire-protection design that is engineered, documented, and stamped. The flexibility is real (creative solutions are possible that the prescriptive path would never permit), but so is the documentation burden.

Two requirements that often surprise first-time developers sit at this boundary:

• Barrier-free access. Under the code as adopted in Nova Scotia, at least one entrance must be barrier-free, and a barrier-free path of travel is required within all normally occupied floor areas on the entrance level, in any storey exceeding 600 m², and in any storey served by a passenger elevator [4]. Accessibility is not a Part 3–only concern.
• The new accessibility standard. Separate from the building code, Nova Scotia's Built Environment Accessibility Standard Regulations (N.S. Reg. 48/2025) apply to newly constructed, newly installed, or redeveloped aspects of the built environment where construction begins on or after April 1, 2026 — though private residences with 3 or fewer dwelling units are explicitly excluded, as are aspects already governed by the Building Code Regulations [5]. A multi-unit project entering construction in 2026 needs to know which of its elements fall under this new standard.

Why the path determines the economics, not just the paperwork

The Part 9 / Part 3 question is upstream of almost every other development decision, and it propagates.

A Part 3 building carries a larger professional team — structural, mechanical, and often fire-protection engineers — engaged from early design through construction field reviews and sign-off. That is real cost and real schedule, and it is incurred whether the building is profitable or not. The municipal review is also more involved: Nova Scotia has no province-wide statutory deadline for permit review, and while typical HRM residential reviews are commonly described as a matter of weeks, multi-unit and more complex submissions are routinely characterized as taking several months — these are practitioner estimates that scale with the completeness of the application, not legislated maximums [6].

A Part 9 building, by contrast, can move through design and review on a shorter, more predictable footing. That difference — in soft costs, in time-to-occupancy, in the certainty of the approval — is frequently the deciding factor in whether a small infill site is worth developing at all.

This is the lens we apply at the feasibility stage. The question is not "how big can this be," but "what is the most valuable building this parcel can support before it tips into a regime whose costs the rents won't carry." On many serviced HRM lots, the answer sits deliberately just under the Part 9 ceiling: a building designed to stay within 3 storeys and 600 m² captures most of the unit yield a small lot allows while keeping the delivery path simple. On lots where the zoning and economics justify it, crossing into Part 3 unlocks a larger, taller, more flexible building — but only when the additional yield clears the additional cost. That trade-off is computable, and it should be computed before the design is committed, not discovered after.

The HRM permitting layer

A point that is easy to miss: the building code is provincial law, but permits, inspections, and occupancy approvals are administered and enforced at the municipal level [7]. In HRM, that means the municipality's Planning and Development office, and it means the fee schedule is HRM's, not the province's.

For new construction or additions to residential buildings of 4 units or fewer, HRM charges its building permit fee per square metre of floor area: $4.04/m² for floors at or above the average finished grade, $3.36/m² for below-grade floors not more than 1.67 m below, and $1.35/m² for deeper basements and garages, subject to a $31.25 minimum (effective April 1, 2024) [8]. For renovations, repairs, and "other residential and all commercial construction," the fee is $6.88 per $1,000 of estimated construction value, again with the $31.25 minimum [8]. (Note that this last basis — value rather than area — is the one that applies to larger multi-unit work, so the permit fee for a bigger Part 3 building is driven by construction value, not floor area.)

Two further municipal facts shape the close of a project:

• Occupancy permit. Under the Nova Scotia Building Code Act, buildings other than single dwellings, sheds, and pools require an occupancy permit before they can be occupied. In HRM, that permit requires a valid building permit and a passed final inspection, and will not be issued while items such as a final lot-grading certificate are outstanding [9]. A multi-unit building is not "done" when construction stops; it is done when occupancy is granted.
• Demolition. If the site has an existing structure, a separate demolition permit is required before it comes down (the HRM demolition permit fee is $62.50, with possible engineering-related fees) [8].

Determining your path: a feasibility checklist

Working out the code path is part of reading what a parcel can carry. The honest version of the exercise runs in this order:

1. Confirm the zoning ceiling first. What the lot is zoned for sets the envelope the building must live inside. In HRM's Regional Centre, for example, the post-2024 Established Residential 3 (ER-3) zone permits up to eight units per lot (lot-size dependent), with a maximum building height of 11 metres plus a 3-metre exemption for a pitched roof [10]. A building's storey count and footprint are constrained by zoning long before the code path comes into play.
2. Measure height in storeys and building area precisely. Small errors here flip the classification. Three storeys versus four, 590 m² versus 610 m² — these are the differences that decide Part 9 versus Part 3, and they should be confirmed against the code's definitions, not estimated.
3. Check the occupancy. A purely residential building keeps the occupancy door to Part 9 open. Add a care use, an assembly space, or a complex mix, and the project is Part 3 on occupancy alone [3].
4. Engage the right professionals at the right moment. A Part 3 project needs engineering and design expertise engaged early — not because the code is a formality, but because performance-based compliance is something you design toward from the start. The expensive failure mode is designing a building under Part 9 assumptions and discovering, after the fact, that a fourth storey or an over-600 m² floor plate has pulled it into Part 3, forcing a redesign of the structural and fire-safety systems.

The cost of getting this wrong is not abstract. A project that has to be re-classified mid-design absorbs the redesign cost, the lost time, and the coordination churn of bringing in a team that should have been there from day one. The cost of getting it right is a single, deliberate decision made while the building is still a set of assumptions on a parcel.

How we approach it

Helio is a technology-led real estate company in Halifax. What we do is determine, for a given parcel, the most valuable building it can support under the zoning and the code, and structure and coordinate that building's development on land our clients own.

The Part 9 / Part 3 line is one of the variables in that calculation. For a small serviced lot, the difference between a building that stays within the Part 9 envelope and one that crosses into Part 3 can be the difference between a project that pencils and one that doesn't — and it is far cheaper to resolve at the feasibility stage than after the drawings are drawn. If you own land in HRM and want to understand what it can carry — and which code path that building would take — that is the conversation we have first.

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Sources

1. Government of Nova Scotia — Nova Scotia Building Code Regulations (N.S. Reg. 198/2024). https://novascotia.ca/just/regulations/regs/bcregs.htm
2. Government of Nova Scotia News Release — "Province to Adopt 2020 National Building Codes" (Sept 20, 2024). https://news.novascotia.ca/en/2024/09/20/province-adopt-2020-national-building-codes
3. National Research Council Canada — Illustrated User's Guide, National Building Code of Canada 2020, Part 9 (Division B): Housing and Small Buildings. https://nrc.canada.ca/en/certifications-evaluations-standards/codes-canada/codes-canada-publications/illustrated-users-guide-national-building-code-canada-2020-part-9-division-b-housing-small-buildings
4. Halifax Regional Municipality — Accessible / Barrier-Free Entrance Design Guidelines (per National Building Code Section 3.8). https://cdn.halifax.ca/sites/default/files/documents/home-property/building-renovating/2024.01-barrier-free-entrance-guidelines-v1.03.pdf
5. Built Environment Accessibility Standard Regulations, N.S. Reg. 48/2025 (Accessibility Act). https://novascotia.ca/just/regulations/regs/accbuiltenviro.htm
6. Halifax Regional Municipality — Building & Development Permits (review timelines per municipal practice). https://www.halifax.ca/home-property/building-development-permits
7. Halifax Regional Municipality — Building Code & Regulatory Information. https://www.halifax.ca/home-property/building-development-permits/building-code-regulatory-information
8. Halifax Regional Municipality — Permit Fees (License, Permit and Processing Fees, Administrative Order #15). https://www.halifax.ca/home-property/building-development-permits/permit-fees
9. Halifax Regional Municipality — Application to Occupy (per Nova Scotia Building Code Act). https://www.halifax.ca/home-property/building-development-permits/commercial-mixed-use-building-permits/application-occupy
10. Halifax Regional Municipality — HAF Amendments / ER Zones Fact Sheet (June 2024). https://cdn.halifax.ca/sites/default/files/documents/about-the-city/regional-community-planning/er-zones-fact-sheet-june-2024.pdf