What is Ontario Building Code garage classification?

The Ontario Building Code establishes garage classifications to regulate construction based on building type and scale. Garages are first categorized as either detached (standalone structures) or attached (connected to a dwelling), which determines the applicable code rules and inspection requirements.

The classification system hinges on dimensional thresholds. A detached garage under a certain footprint and height may qualify for simplified documentation, while larger detached structures or any attached garage above specified size limits typically require a full permit set with engineered drawings. Attached garages are generally treated more stringently since they affect the main dwelling's fire separation and structural integrity.

For builders and homeowners, this classification directly impacts the submission process. Garages meeting code criteria for simplified approval can often proceed with basic construction drawings and a streamlined review. Those exceeding thresholds must include full structural plans, foundation details, and calculations prepared by a licensed professional engineer or architect. The height threshold (usually measured to the eaves or peak) and total floor area are the primary factors builders reference when determining which documentation path applies.

Understanding where a project falls in the classification system is critical for budgeting timeline and compliance. Garage builders and permit specialists in Ontario use these thresholds to advise clients on documentation scope and to prepare appropriate submittals to municipal authorities.