Check a design
- Enter the numbers to check them.
The checker covers the city-wide Zoning By-law 05-200. Parts of Hamilton still use a former town's by-law with its own ADU rules (the areas page lists them), and a heritage property, a creek or the escarpment can add approvals.
Which rules does it check?
| Rule | Limit |
|---|---|
| Floor area | The smaller of 75 m² or the floor area of the house |
| Side and rear lot lines | At least 1.2 m |
| From the house | At least 4.0 m |
| Height | 6.0 m at most, no balcony or rooftop patio above the first floor |
| Lot coverage | All buildings together cover 45% of the lot at most |
| Not checked here | Rear or interior side yard only; the 1.0 m access path; 12.0 m² of landscaped rear yard |
From section 4.33.2 of By-law 05-200 as written by By-law 22-132 and amended by By-law 25-033 (City of Hamilton By-law 25-033, read November 5, 2026); the ADUs page has the full table.
What comes after it fits?
Water and sewer through the house, a path for firefighters and a builder for a new home: water, sewer and access for a garden suite. The two kinds of ADU side by side: basement unit or garden suite. A grading plan may be needed: lot grading plans. If a number does not fit, a minor variance is the route.