What is the minimum footing size for a house in Ontario?
For typical houses on stable soil, OBC tables set minimum strip footing widths that increase with storeys supported — commonly 250 mm for one storey, 350 mm for two and 450 mm for three — with footings at least 100 mm thick and not thinner than their projection beyond the wall.
Paraphrased for clarity — open this provision in the BUILDAiD Library for the exact wording.
The tables assume soil with adequate allowable bearing pressure, roughly 75 kPa or better; softer soils, fill, or unusual loads push the design to Part 4 engineering. On real projects, the details that matter are keeping footings on undisturbed soil or engineered fill, stepping footings correctly on sloped sites, and enlarging footings under point loads such as teleposts and fireplace masses. Adding a storey during design, or a heavy finish like full-height stone veneer, can silently change the required footing width, so revisit the table whenever loads change.
Footings are the concrete pads your whole house stands on. The code gives simple minimum widths that grow as the house gets taller — roughly 250 mm for a bungalow wall and wider for two or three storeys — provided the soil under them is firm and undisturbed.
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This page is provided for general information. Building code requirements depend on your specific project, occupancy and municipality, and code editions change. Always verify requirements against the current Ontario Building Code and confirm with your local building department.