What happens if I built something without getting a legally required minor variance first?

Building something that doesn't comply with the zoning bylaw without first obtaining the required minor variance generally puts you in violation of the bylaw, which can expose you to municipal enforcement action, including an order to bring the structure into compliance or, in a serious case, an order requiring the non-compliant portion to be removed or altered. Municipalities can also generally prosecute zoning bylaw violations, which can carry meaningful fines separate from any compliance order.

A property owner in this position can generally still apply for a minor variance after the fact, sometimes called a retroactive application, seeking to have the existing, already-built condition legalized through the normal committee of adjustment process. This doesn't guarantee approval; the committee applies the same four-part test regardless of whether the structure already exists, and having already built something without approval doesn't create any special entitlement to have it approved now, though in practice a completed structure that otherwise fits the neighbourhood may sometimes fare reasonably in that assessment. Given the risk of an unfavourable outcome and potential enforcement in the meantime, getting legal advice promptly, rather than waiting for a complaint or inspection, is the safer course.