This article reproduces rules as published by the Province of Nova Scotia and Halifax Regional Municipality, with retrieval dates. It is general information, not legal advice — confirm the specifics of your project with the municipality or the province before you rely on it.
"How many units before I need an architect?" is the wrong shape of question in Nova Scotia. The Architects Act doesn't count units past two — it switches on occupancy class, building area and storeys. Here are the thresholds exactly as section 56(2) prints them, then the gap between the statute and the municipal checklist that catches people.
The statute's own definitions
(b) "building area" means the greatest horizontal area of a building above grade within the outside surface of exterior walls or within the outside surface of exterior walls and the centre line of firewalls; (c) "building height", in storeys, means the number of storeys contained between the roof and the floor of the first storey;
Architects Act, SNS 2006, c. 12, s. 56(1)(b)–(c) — retrieved August 30, 2026 from CanLII.
The exemption, occupancy group by occupancy group
Section 56(2)(a) permits the practice of architecture by non-architects for the following buildings, quoted verbatim in our companion article. Stated as thresholds:
- One-dwelling or two-dwelling units — exempt as such, with no area or storey cap in the clause.
- Residential, business and personal services, mercantile, and low/medium-hazard industrial occupancies — exempt up to three storeys and a building area of 450 m².
- Assembly occupancies (churches, restaurants, schools, theatres and the like) — exempt up to one storey and 200 m².
- High-hazard industrial occupancies — exempt up to one storey and 200 m².
- Care and treatment occupancies are not listed in s.56(2)(a) at all — no exemption threshold exists for them in this clause.
So the direct answer: a duplex needs no architect under the Act. A three-unit residential building is not a one- or two-dwelling unit, so it falls to clause (ii) — exempt only while it stays at or under three storeys and 450 m² of building area. Past either threshold, the Act requires a licensed architect.
The 450–600 m² wedge
Here is the nuance this article exists for. HRM's own permit guidance draws its residential/commercial line at a different place: on its New Home Construction page (retrieved August 30, 2026), the municipality states that residential building permits apply to buildings of 600 m² or less and three storeys or less, with larger buildings handled as commercial/mixed-use. The municipality's commercial renovation document table uses the same 600 m² boundary.
The Architects Act bites at 450 m² for the occupancy classes in clause (ii). That leaves a wedge — buildings between 450 m² and 600 m² — where the municipal intake track treats the project as residential and its published document lists are silent on professional design, while the Act already requires a licensed architect. The Act is the statute; the checklist is an intake aid. Where they diverge, the Act governs.
If your project sits between 450 and 600 m², do not read HRM's checklist silence as permission. The Act's threshold is the binding one — confirm with the province or the Nova Scotia Association of Architects before proceeding without a licensed architect.
A secondary reading, labelled as such
The Nova Scotia Association of Architects publishes a scope table summarizing where a licensed architect is required — Group A assembly over 200 m² or two storeys, all care-and-treatment facilities regardless of size, and residential, business, mercantile and industrial buildings over 450 m² or four storeys (retrieved August 30, 2026 from nsaa.ns.ca). It is the association's interpretation of the Act and Building Code together, not the statute itself; where its phrasing differs from s.56(2) above — for instance, four storeys against the statute's three — the statutory text governs.
One more thing the table gets right: a professional engineer licensed in Nova Scotia, with specific experience designing buildings of the relevant type, is also permitted by law. The choice is not always architect-or-nobody.