St. Catharines zoning for small homes

Backyard suite

A separate home in the yard of a house: garden suite, laneway suite or coach house, including prefab, modular or container units used this way.

Allowed · St. Catharines’s term: “detached accessory dwelling unit”

Up to two accessory dwelling units are permitted with a detached, semi-detached or townhouse dwelling, either inside the principal dwelling or in an accessory structure, in the R1 to R4 residential zones (and other zones listed in the by-law). Detached units in Agricultural zones are permitted only where a site-specific special provision allows them. [1][2]

Number allowed: Maximum of two accessory dwelling units per detached, semi-detached or townhouse dwelling (s. 2.2.1) [3]
Maximum size: Floor area of an accessory dwelling unit shall not exceed 80 m² (s. 2.2.1 a) [3]
Maximum height: 4.5 m for walls/supporting posts and 6 m to the roof peak (accessory structure limits, s. 2.1 d, applied by s. 2.2.1 b) [3]
Setbacks: 1.2 m from rear and interior side lot lines (3 m within a private road development); not in a front yard or required exterior side yard (s. 2.2.1 b, 2.1 b) [3]
Separation from house: Minimum 3 m distance between buildings (s. 2.2.1 b) [3]
Parking: 0.5 parking spaces per accessory dwelling unit (s. 3.12.1) [3]
Where allowed: Permitted in R1, R2, R3, R4 (and M1-M3, I1-I3, A1 as an accessory use); in Agricultural zones A1-A3 a detached unit needs a Section 13 special provision (s. 2.2.1 d) [3]
Approvals: Building permit required; City offers pre-approved detached ADU designs (Building Code only, zoning still reviewed per property) [2]

Ontario-wide rule

Ontario law stops municipalities from banning one residential unit in a building ancillary to a detached house, semi-detached house or rowhouse on a parcel of urban residential land, as long as the lot has no more than three units in total. Municipalities still set most other zoning rules, but provincial law limits parking requirements, minimum unit size, lot coverage and separation distances. These units are also exempt from development charges and parkland dedication. [4][5][6]

Tiny home on a foundation

A small house as the main home on its own lot. The key rule is any minimum dwelling size.

Allowed · St. Catharines’s term: “detached dwelling”

The consolidated by-law sets no minimum dwelling unit floor area for detached dwellings in the residential or agricultural zones; lot area, frontage, setback and height rules apply.

Minimum dwelling size: No minimum dwelling floor area found in the R1-R4 or A zone regulations [3]

Ontario-wide rule

Ontario law sets no minimum total size for a house that is the main dwelling. The Building Code sets minimum room areas, so the smallest compliant dwelling is roughly 17.5 m² by the Province's own estimate. Municipalities may still set minimum floor areas for main dwellings in their zoning by-laws. The provincial ban on minimum sizes covers only additional residential units. [4][7][8][9][10][11][12]

Tiny home on wheels or park model

Living full-time in a tiny home on wheels or a park model home.

Not addressed · St. Catharines’s term: “recreation vehicle / recreation trailer”

The by-law has no mobile home or trailer park zone and does not list trailers or mobile homes as dwellings; recreation vehicles and trailers are addressed only through parking rules. A detached dwelling is defined as a building, and accessory structures may not be used for habitation except as an accessory dwelling unit.

Where allowed: No mobile home, trailer park or recreation vehicle dwelling use appears in the permitted uses table [3]
Temporary garden suite: No garden suite or temporary-use provision found in the consolidated by-law [3]

Ontario-wide rule

Ontario has no single rule for living full-time in a tiny home on wheels. A unit on wheels can count as a 'building' that needs a permit and must meet the Building Code once it stays in one place, is hooked up to services or is anchored. Park model trailers are recognized only as seasonal recreational buildings. Municipalities may allow a portable garden suite under a temporary-use by-law for up to 20 years, with extensions of up to 3 years each. [12][7][4][9][8]

Bunkie or sleeping cabin

A small sleeping building with no kitchen, usually beside a cottage or house.

Not allowed · St. Catharines’s term: “accessory structure”

Accessory buildings and structures may not be used for habitation except as an accessory dwelling unit, and habitation is defined to include sleeping accommodation.

Kitchen: Not applicable: s. 2.1 a) bars habitation in accessory structures; 'Habitation' means living, residing or occupying a space for shelter and sleeping accommodation [3]

Ontario-wide rule

Ontario law has no rule written specifically for bunkies or sleeping cabins. Whether one needs a building permit depends on the Building Code Act's definition of 'building' and the Code's shed exemption. That exemption covers only storage-use sheds, so it does not cover a structure used for sleeping. Municipal zoning rules for accessory buildings still apply. [9][7][4][13]

Official links

Last confirmed October 2026.

Notes and caveats

Read the consolidation to Amendment No. 90 (By-law 2024-032, passed April 8, 2024). The City's zoning page warns recent amendments may not be included; later site-specific amendments (e.g. By-law 2025-063) are not consolidated and were not checked. The pre-approved design page says the ADU grant program was depleted for 2025.

Sources

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St. Catharines zoning for small homes

Backyard suite

Ontario-wide rule

Tiny home on a foundation

Ontario-wide rule

Tiny home on wheels or park model

Ontario-wide rule

Bunkie or sleeping cabin

Ontario-wide rule

Official links

Sources

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