Design ProcessCustom Homes

Building Designer or Architect? Who Can Design Your Home in BC

Written by Arcadia Design · October 30, 2026Last reviewed: October 30, 2026

Bespoke custom home in South Surrey designed by Arcadia Design, a building design firm

One of the first questions people ask when they start planning a custom home is whether they need an architect.

It is a fair question. Most people do not design buildings for a living, and the difference between an architect, a building designer, and an engineer is not always obvious.

The short answer in British Columbia: for most single-family homes, duplexes, and small multi-unit buildings, you do not need an architect. A building designer can design them. But there are clear lines where an architect is required, and it helps to know where those lines are before you start.

What Decides Who Can Design a Building in BC

In BC, the Architects Act and the Architects Regulation set out which buildings must be designed by an architect. This is often called reserved practice.

The BC Building Code also splits buildings into two broad groups. Part 9 covers houses and small buildings. Part 3 covers larger and more complex buildings. The Architects Regulation sets its own limits, so the question is not only which part of the code applies, but whether the building falls inside the regulation's thresholds.

When an Architect Is Required

For residential projects, an architect is generally required when a building has any of the following:

A building area (footprint) of 600 m² or more
4 or more storeys
5 or more dwelling units
A mixed-use design with dwelling units and a gross area of 470 m² or more

For commercial buildings, such as offices, retail, and personal service spaces, the threshold is generally a gross area of 470 m² or more. Certain industrial and assembly buildings have their own rules.

These thresholds come from the Architects Regulation and can change. Your municipality may also have its own requirements, so it is always worth confirming for your specific project.

What a Building Designer Can Design

Below those thresholds, a building designer can prepare the design and the drawings needed for permit. For homeowners and builders in the Lower Mainland, that covers a large share of projects:

Custom single-family homes
Duplexes and houseplexes with up to four units per building
Secondary suites, garden suites, and coach houses
Renovations and additions
Farm residences, barns, and agricultural buildings
Smaller commercial buildings within the size limits

Completed duplex in Surrey, BC designed by building design firm Arcadia Design — SURREY FIRST DUPLEX, designed by Arcadia Design from concept through completion

Where Engineers Fit In

Whether your project is designed by a building designer or an architect, other professionals are often part of the team. Depending on the project, that can include a structural engineer, a geotechnical engineer, a surveyor, and an energy advisor for BC Energy Step Code compliance.

A good designer coordinates these consultants so the drawings work together and the permit application moves smoothly. You should not have to manage each one on your own.

So Which Should You Choose?

If your project falls under the architect thresholds, the decision is made for you. If it does not, the question becomes which professional is the best fit for the work.

For most custom homes and small multi-unit projects, a building designer who works on these projects every day is a natural fit. Residential design is the focus, local permit processes are familiar, and the design is shaped around how the home will actually be lived in.

What to Look For in a Home Designer

Whoever you hire, a few questions will tell you a lot:

Have they designed projects like yours, in your municipality?
Can they show you completed homes, not only renderings?
Do they review zoning and site constraints before starting design?
Will they coordinate engineers and other consultants?
Do they prepare the full drawing set for building permit?
Will they tell you early if your project needs an architect or special approvals?

See how our custom home design process works Read: Zoning and Permits, Explained

Planning a Home in the Lower Mainland?

Arcadia Design is a building design firm based in Langley, working with homeowners, builders, and developers across Surrey, the Fraser Valley, and Metro Vancouver. If you are not sure who should design your project, start with a conversation. We can review your property, explain what applies, and let you know early if anything requires additional professionals.

This article is general information only. Requirements depend on the specific building and property and should be confirmed with your local government and the appropriate professionals.

Frequently Asked Questions

Do I need an architect to design a house in BC?

Usually not. Under the Architects Regulation, most single-family homes and small residential buildings with up to four dwelling units, three storeys or less, and a building area under 600 m² can be designed by a building designer. Larger or more complex buildings require an architect.

Can a building designer design a duplex in BC?

Yes. Duplexes and other residential buildings with up to four dwelling units generally fall below the threshold that requires an architect, provided the building is also under the storey and building area limits.

When is an architect required in BC?

For residential buildings, an architect is generally required when a building has a building area of 600 m² or more, four or more storeys, five or more dwelling units, or is mixed use with dwelling units and a gross area of 470 m² or more. Commercial buildings generally require an architect at 470 m² or more.

Will I still need an engineer if I hire a building designer?

Often, yes. Many projects need a structural engineer, and some need a geotechnical engineer or energy advisor. A building designer typically coordinates these consultants as part of the design and permit process.