Accessory Dwelling Units in Richmond Hill - Design, Permits, Construction

The Oak Ridges Moraine Conservation Plan covers Richmond Hill's northern third, and on those Jefferson and Oak Ridges lots the tree-protection and grading requirements routinely cost more than the ADU's foundation. We price a moraine site and a Crosby site as two different classes of project. Richmond Hill permits additional dwelling units subject to Oak Ridges Moraine Conservation Plan constraints on the northern third of the town.

Sloped and treed lots along the moraine where site grading and tree protection drive cost more than the building itself. Richmond Hill sees 139 cm of snow and -4.6°C winter averages. Ontario's 1.2 m frost-depth requirement governs every footing we pour for accessory dwelling units, and the April-November season sets the excavation window.

Four physical forms are available on a Richmond Hill lot - detached garden suite or laneway house, an internal basement or upper-floor suite, a garage conversion, and a factory-built module - and the lot itself, not preference, usually decides which two are realistic. We run a feasibility overlay on the parcel first - zoning envelope, servicing capacity, rear-yard access - and only then price the two forms that survive it. Bill 23 permits up to three residential units as-of-right on most serviced Richmond Hill lots, which removes the rezoning application from the default path.