Secondary Suites 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 secondary suites, and the April-November season sets the excavation window.

"Secondary suite" is the Ontario planning term for a second self-contained dwelling inside the existing house, so the review in Richmond Hill turns on the interior - separate kitchen and bath, an exit that does not pass through the primary unit, and rated separation between the two. Because the shell already exists, the schedule is driven by inspection sequencing rather than by weather: rough-in, framing and insulation inspections gate one another regardless of the April-November season. Bill 23 makes up to three units as-of-right on most serviced Richmond Hill lots, so a secondary suite generally proceeds by building permit alone without a rezoning application.