This article summarizes the rules as each province publishes them, read on 27 September 2026. It is general information, not legal advice: confirm the specifics of your project with your building department.
Many people assume a new house needs an architect's or engineer's stamp before it can get a permit. For a house built within Part 9 of the building code, that is generally not the case in Alberta, British Columbia, Nova Scotia, Ontario or Quebec. The building department that issues your permit reviews the plans, and inspects the work as it goes up. Below is what each province requires, and where the rule comes from.
The short answer
- No architect or engineer is generally required for a house built within Part 9 in the five provinces covered here.
- Your building department reviews the plans when you apply for a permit, and inspects the work at set stages.
- Ontario asks who designed it. Anyone who designs a house for someone else needs a provincial qualification, a BCIN, unless they are an architect or engineer. An owner who designs their own house is exempt.
- Quebec draws a size line for architects. A detached house of two storeys or less, with one basement at most and a gross area under 600 m², needs no architect.
- An engineer comes in where the house leaves Part 9's rules: a beam or joist the Part 9 tables do not size, ground conditions outside Part 9, or a structure designed by calculation.
- The building department can still ask. Alberta's code, for one, lets it require a professional when a project's size or complexity raises safety concerns.
What Part 9 covers
Part 9 of the National Building Code, as each province adopts it, covers houses and small buildings: three storeys or less in building height, a building area of 600 m² or less, and a residential, business, mercantile or low-hazard industrial use (Division A, Article 1.3.3.3.). Most detached, semi-detached and row houses fall within it. Its rules are prescriptive: tables of spans, sizes and clearances a builder can follow without calculations.
The national code does not decide who must design or sign a house. It leaves that to each province, and its own note on structural design says so: the need for professional involvement is defined by provincial and territorial legislation (Note A-9.4.1.1.).
Alberta
Alberta's edition of the code says the involvement of a registered professional is not required for a single-family dwelling, or for a building of four dwelling units or less, and a secondary suite does not count as a unit (Division C, Sentences 2.4.1.1.(1) and (2)). The authority having jurisdiction may still require one where a project's size or complexity raises special safety concerns (Sentence 2.4.1.1.(4)). A design done to Part 4, the engineering part of the code, must be by a registered professional (Article 2.4.1.2.).
British Columbia
The BC Building Code applies its professional design and field review requirements to buildings under Part 3, to Part 9 buildings with shared exits and firewalls, and, for any other Part 9 building such as a house, to four things only: structural components outside Part 9, geotechnical conditions outside Part 9, sprinkler systems designed to NFPA 13, and standpipe systems designed to NFPA 14 (Division C, Article 2.2.7.1.). For an ordinary house, professional review is needed only for the parts that go beyond Part 9.
Nova Scotia
Nova Scotia's Architects Act lets people other than licensed architects practise architecture for a one-dwelling or two-dwelling unit, unless a licensed architect is otherwise required by law or by the building authority (section 56(2)). The Building Code Regulations require an engineer for a structural component whose sizes Part 9 does not give. The owner of a Part 9 building calls the building official in at seven stages of construction for inspection. Our guide Do you need an architect to build a house in Nova Scotia? quotes the Act in full.
Ontario
Ontario regulates designers rather than requiring an architect. A building permit application names the house's designer on Schedule 1, and the designer declares one of three things: they act for a registered firm and hold a BCIN, they hold a BCIN themselves, or the design is exempt from qualification and registration. Licensed architects and engineers do not complete Schedule 1. Anyone who designs a house for someone else needs the BCIN qualification in the House category; municipal guidance, such as the City of Mississauga's notice to designers, lists the owner of a house who designs it as exempt from both. Some municipalities, Toronto among them, also ask for the designer's name and BCIN on the drawings.
Quebec
Quebec's Architects Act reserves the plans of a building to architects, with exceptions in section 16.1. A detached single-family house needs no architect if, once built, it has no more than one basement storey, a building height of no more than two storeys and a gross area under 600 m². A semi-detached or row house, or a building of up to four dwelling units, is exempt under the same conditions with a gross area under 300 m². So a three-storey house, or a detached house of 600 m² or more, needs an architect. Quebec's Engineers Act likewise does not reserve to engineers the structure or the mechanical, thermal and electrical systems of a building, other than an industrial one, where Part 9's acceptable solutions are applied in full (section 3).
Where an engineer comes in
In every province covered here, a house stays within Part 9 as long as its structure follows the Part 9 tables. A beam longer than the span tables allow, an engineered floor system, a foundation on difficult ground, or anything designed by calculation brings in an engineer for that part. The rest of the house can still be designed without one.
What your building department does
Whoever draws your plans, the building department decides. It reviews your permit application against the code in force, asks for anything missing, issues the permit, and inspects the work at set stages from the footings to occupancy. A plan that has been checked against the code before you apply is simply one with fewer surprises at that desk.
Provinces not covered yet
This guide covers the five provinces whose rules we have read in their own words. Saskatchewan, Manitoba, New Brunswick, Prince Edward Island, Newfoundland and Labrador and the territories come next. Until then, ask your building department.
How Ridgeplate fits
Every Ridgeplate floor plan for a house in Canada is checked against the National Building Code as your province adopts it, with each article checked and its result listed on the drawing. The permit notes on every sheet list what your permit application still needs, such as structural design, energy compliance and a site plan.
Sources
- National Building Code of Canada 2020: Division A, Article 1.3.3.3.; Note A-9.4.1.1.
- National Building Code 2023 Alberta Edition: Division C, Articles 2.4.1.1. and 2.4.1.2.
- British Columbia Building Code 2024: Division C, Article 2.2.7.1.
- Nova Scotia: Architects Act, SNS 2006, c. 12, s. 56(2); Building Code Regulations.
- Ontario: Application for a Permit to Construct or Demolish (2024 Building Code), Schedule 1: Designer Information; City of Mississauga, notice to building permit applicants and designers.
- Quebec: Architects Act, CQLR c A-21, ss. 16 and 16.1; Engineers Act, CQLR c I-9, s. 3; read on LégisQuébec, 27 September 2026.