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When Do You Need an Architect?

To protect public health, safety, and welfare, the Architects Act defines architecture and sets out which types of buildings in Ontario require an architect by law—this includes most public-use and large buildings.

But whether or not your project legally requires an architect, there are always significant advantages to retaining one. Architects are highly skilled professionals with extensive training and experience, and are able to help you through the complex regulatory building requirements—including zoning bylaws, building codes, and the construction process.

Architects serve as trusted professional advisors. Their role is holistic, blending diverse requirements and disciplines in a creative process, while serving the public interest and addressing health and safety matters. Good architecture provides a sense of place and support of all types of human activity. It allows built forms to fit in harmony with their surroundings while promoting health and well-being, enriching lives aesthetically and spiritually, providing economic opportunities, and creating a legacy that contributes to a sustainable built environment.

Under the Architects Act, an architect must be retained any time architectural services are being provided on a building requiring an architect. This means as soon as building planning and design begins, an architect is needed, no matter how conceptual or schematic the services may be.

In terms of applications to authorities having jurisdiction (AHJs)—such as local governments and municipal districts—the legal requirement begins with (re)zoning and development permit applications that include one or more buildings requiring the services of an architect. AHJs must comply with the Architects Act, which means they cannot process applications for those buildings until an architect has been retained.

The OAA works regularly with architects, engineers, planners, building officials, designers, and owners to assist in determining whether a particular project—or project stage, such as formal application to a local government—must have an architect on the job.

In Ontario, the law requires an architect to be responsible for the design and construction of most public use and large buildings. However, Section 11 (3) of the Architects Act includes a number of “exceptions” by which certain building types and sizes are exempted from the general requirement for architects. Please refer to the Joint Bulletin by the OAA and the Professional Engineers of Ontario (PEO) for a summary of the Design and General Review Requirements for Buildings in the Province of Ontario. You can also read Professional Requirements for the Built Environment in Ontario, which is an overview of the protected scope, title, and seal, the OAA’s regulatory role, and how to report misconduct or illegal practice. It also clarifies when an architect is needed for a project.

The Architects Act also establishes legal liability for those who misrepresent themselves as architects, or who practise architecture (or enable it) by non‐architects. This liability extends to AHJs who elect to process applications in contravention of the Act.

When in doubt, do not hesitate to contact the OAA’s Office of the Registrar ( to confirm whether the Architects Act applies to a particular project. Staff will respond promptly to help all parties understand how to comply with their legal requirements as they relate to the Act.


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