What records explain additional dwelling units at a Sault Ste. Marie home?

The City's page says its zoning by-law does not define additional dwelling units as such: it permits residential structures, buildings of one or more dwelling units, in the R1 to R5 residential zones and some other zones. In the Gentle Density Residential (R2) zone, which the by-law says is designed for most of the city's single-detached neighbourhoods, a lot may have one or more residential structures, and the City says there is no hard cap on the number of units as long as the building rules for storeys, setbacks, parking and the like are met; in R2 those include a lot of at least 550 m² with 15 m of frontage (650 m² and 18 m beside Lake Superior or the St. Mary's River), two storeys and 40% lot coverage. The Estate Residential (R1) zone and the Rural Area zone allow at most two dwelling units per lot.

A unit can sit inside the house, be attached to it, or stand apart as a garage flat or coach house, and the City's page shows designs for detached units that its Building Department has reviewed. A permission in the zone does not make an existing basement apartment lawful; the building permit and its inspections are the records that do.

• Additional Dwelling Unit (ADU) Initiative: the City's page on what the zoning permits and the designs for detached units
• Zoning By-law 2005-150, office consolidation May 2026: the R1 and R2 zones and their building rules (PDF)

Extra units allowed is in the free check as a summary of the City's rule, from our hand-kept table of city rules, and the full report reads the lot's zone where the City's zoning map is open data we can use; where it isn't, the report's line says where the City publishes it. Neither is confirmation that a particular unit holds a permit or may be occupied.

Free check: pick “Extra units allowed” See the sample report