Garden suites & ADUs · Dundas
Garden Suites in Dundas
Dundas sits in the valley below the escarpment, with mature trees, older homes and creeks running through town. Those are what usually decide where a garden suite can go on a Dundas lot.
The rules, in plain language
What Dundas allows
Dundas is part of the City of Hamilton, so Hamilton's detached additional dwelling unit (D-ADU) rules in Zoning By-law 05-200 apply where your lot is zoned under 05-200. Some properties may still fall under a former Dundas zoning by-law. Check your address on Hamilton's Interactive Zoning Map. For the full breakdown, see our Hamilton garden suite guide.
Size
- Gross floor area up to the lesser of 75 m² or the gross floor area of the main house.
- If the main house's ground floor is 105 m² or less, the suite's ground floor can't exceed 70% of it.
- Combined lot coverage of all buildings on the lot is capped at 45% (By-law 25-033, 2025).
- Source: By-law 22-132, as of November 1, 2026
Height
- Maximum height 6.0 m.
- No balconies or rooftop patios above the first floor.
- Source: By-law 22-132, as of November 1, 2026
Location and setbacks
- Rear and/or interior side yard only.
- At least 1.2 m from the interior side and rear lot lines. Eaves and gutters may project up to 0.45 m.
- In the rear yard, at least 4.0 m from the back of the main house (reduced from 7.5 m by By-law 25-033).
- In an interior side yard, at least 4.0 m from the house's side wall and 5.0 m behind its front façade.
- At least 12.0 m² of landscaped area must remain in the rear yard.
- Source: By-laws 22-132 and 25-033, as of November 1, 2026
Access and servicing
- A clear path at least 1.0 m wide and 2.1 m high from the street to the suite entrance. City laneways can't provide fire access.
- Water and sewer must connect through the main house. Separate servicing to the street isn't permitted.
- The water service may need upgrading; a water pipe sizing form is required.
- Source: City of Hamilton: ADUs, as of November 1, 2026
Parking
- In the urban zones above, no extra parking space is required for the ADU, as long as the parking that existed on May 12, 2021 is kept.
- Source: By-law 22-132, as of November 1, 2026
Permits, fees and charges
- A building permit is required, applied for online through my.hamilton.ca.
- A grading plan may be required, and a Good Neighbour notice applies to detached ADUs.
- New detached ADUs need a Tarion-registered builder (or owner-builder details).
- A municipal address is required (extra fees).
- Heritage, conservation authority or Niagara Escarpment approvals may apply.
- The city says an ADU may be subject to parkland and development charges, set during permit review.
- Source: City of Hamilton: ADUs, as of November 1, 2026
Check with the city: confirm which zoning by-law covers your Dundas lot. The city says properties in Heritage Conservation Districts need a heritage permit, and conservation authority approval applies on regulated land, which is common near creeks and the escarpment. The numbers below come from Hamilton's amending by-laws 22-132 and 25-033. ADU Zoning: ADUzoning@hamilton.ca, 905-546-2424 ext. 2719.
How we build it
Five ways to build in Dundas
01
Geohaus factory-built
Perimeter Homes is a Geohaus partner. Studio, one- and two-bedroom layouts built in a factory and set on your lot.
See the Geohaus layouts02
Modular / prefab
Factory-built modular garden suites and backyard homes, with sizes adjustable to your lot and local rules.
Browse the model gallery03
Custom stick-built
Framed on site for tight, sloped or oddly shaped lots, or a layout no catalogue covers.
How custom worksEvery design still has to fit Dundas's zoning for your lot. We check that before you commit.
Common questions
Dundas garden suite FAQ
Do Hamilton's rules apply in Dundas?
Yes, Dundas is part of the City of Hamilton. See our Hamilton guide for the full rules, and confirm your lot's zoning.
My house is in a heritage district. Can I still build?
Possibly, but the city says a Heritage Permit is required for designated properties and properties in Heritage Conservation Districts.
What about creeks and the escarpment?
Lots on conservation authority or Niagara Escarpment Commission land need development approval from that agency.
How tall can a detached ADU be?
Under Hamilton's By-law 05-200 as amended, 6.0 m, with no balconies or rooftop patios above the first floor.
Sources
Official city sources
- City of Hamilton: Additional Dwelling Units (as of November 1, 2026)
- By-law 22-132 (ADU amendments to Zoning By-law 05-200) (as of November 1, 2026)
- By-law 25-033 (Ontario Regulation 462/24 updates) (as of November 1, 2026)
- City of Hamilton: Zoning By-law 05-200 (as of November 1, 2026)
This guide summarizes public city information and isn't planning or legal advice. Rules change. Confirm your lot with the city before you apply.
Start here
Talk to a garden suite builder.
Tell us about your lot and which option you're considering. We reply within one business day.