Designing Your Home? Do you need an Architect?

A client purchased a vacant lot in Muskoka. He asked us “What are the regulations in Muskoka in regards to an individual designing their own home or cottage? Am I allowed to submit my own drawings and do I need to be registered with the Ministry and have a BCIN number?

For this question, I reached out to Jason Lowe, B.ARCH OAA AAA AIBC – Architect, and Director of the Huntsville office of Mitchell Jensen Architects.  Following is his response.

Note: italicized terms below relate to Ontario Building Code (OBC 2012) definitions.

The short answer to the questions above is that homeowners, themselves, are exempt from the requirement to have a BCIN number if their “design activities relate only to the construction of a detached house, semi-detached house, townhouse or row house owned by that person and containing not more than two dwelling units in the house” (OBC 2012). An Owner is also permitted to design an ancillary building, such as a garage, that serves the house, without a BCIN number.

There are limitations to the size, height, number, and location of dwelling units in each house that may require the engagement of an Architect and/or a Professional Engineer.

Architects design all sizes of houses and additions; however, the following five criteria define when an Architect (and/or Professional Engineer) must be engaged in the design of a residential occupancy:

  1. The building exceeds 3 storeys in building height (Architect and Professional Engineer are required).
  2. The building exceeds 600m2 (6,458 sq.ft.) gross area that contains a residential occupancy other than a dwelling unit or dwelling units (a hotel for instance). Gross area is the total of all floors above grade measured to the outside of the exterior walls.
  3. The building exceeds 600m2 gross area and contains one dwelling unit above another dwelling unit.
  4. The building exceeds 600m2 in building area, contains 3 or more dwelling units and has no dwelling unit above another dwelling unit, for instance a group of row homes. Note the difference here between gross area and building area. Building area is the greatest horizontal area of a building above grade. For example, if the second level of your home partially overhangs the first level, the overhanging area must be translated down to grade and added to the main level to determine the building area. Similarly, for any other overhangs on subsequent levels.
  5. Every building that exceeds 600m2 in gross area or 3 storeys in building height.

A “Dwelling unit” is a specific building code term defined as “a suite operated as a housekeeping unit, used or intended to be used by one or more persons and usually containing cooking, eating, living, sleeping and sanitary facilities” (OBC 2012). The term suite in this context implies a separate tenancy, such as a rental apartment within the overall house that is distinct from the primary residence. Architects and Professional Engineers are exempt from the BCIN requirements. Architects are independently governed by the Architect’s Act which is a different law than that of the Building Code Act.

If you are the Owner, and are considering a project, and decide to have someone else prepare the design and drawings of your new home or addition then you have a few choices:

  1. Hire an Architect! (Licenced professional)
  2. Hire a “Person engaged in the business of providing design activities to the public”. (Registered BCIN).
  3. Hire a registered Tarion home builder who offers design services. (Qualified BCIN)
  4. If your project is limited to an “addition, material alteration or repair of a detached house, semi-detached house, townhouse or row house containing not more than two dwelling units in each house” you can hire an “Other Designer” as the code defines them. (Also a Qualified BCIN)

Thanks for helping me to answer this question, Jason.   I am often asked about the choices one has when designing a home. In a subsequent blog, I’ll ask you to go into more detail about these four choices.

If you have questions regarding building and design, you can reach Jason at




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