Cornwall zoning for small homes

City of Cornwall, a single-tier municipality. Population 47,845 (2021 census).

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 · Cornwall’s term: “additional residential unit (in an ancillary building)”

One additional residential unit is permitted in a building ancillary to a single-detached, semi-detached or duplex dwelling where adequate water and sanitary services are available, provided the lot has no more than three units in total. A separate, temporary 'garden suite' is also defined but needs a site-specific temporary use by-law. [1][2]

Number allowed: One unit in an ancillary building, if the main dwelling contains no more than two units (s.3.4) [1]
Maximum size: Gross floor area must be equal to or less than that of the main dwelling unit(s); where the ancillary building also contains a garage, maximum footprint 60 m² [1]
Setbacks: Subject to the main-dwelling provisions of the zone, except a minimum 3 m rear yard; no closer to the front or exterior lot line than the main building [1]
Separation from house: At least 4 m from another building or structure containing a residential unit, unless the zone permits less [1]
Parking: 1 space per dwelling unit; may be tandem with the main dwelling's space; no new driveway solely for the unit [1]
Servicing: Adequate public or private water and sanitary sewer services required [1]

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. [3][4][5]

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 · Cornwall’s term: “single-detached dwelling”

The RES 10 zone standards for single-detached dwellings set lot, setback, coverage and height limits but no minimum dwelling floor area; no minimum was found in the by-law for the residential or agricultural zones. [1]

Minimum dwelling size: None stated in the RES 10 zone standards (s.4.2) [1]
Minimum lot size: RES 10: 464 m² with full municipal services; 696 m² with one service; 2,788 m² with neither [1]

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. [3][6][7][8][9][10][11]

Tiny home on wheels or park model

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

Allowed with limits · Cornwall’s term: “mobile home / residential mobile home park; recreational vehicle”

Mobile homes are provided for in the Residential 50 (RES 50) Mobile Home Park zone, which permits only residential mobile home parks. A recreational vehicle may be used as temporary accommodation only while a damaged dwelling is being rebuilt; the RV definition expressly excludes park model trailers and tiny homes, which the by-law does not otherwise address. [1]

Where allowed: Residential 50 (RES 50) zone: residential mobile home park only (minimum park area 4 ha, full municipal services) [1]
Minimum dwelling size: RES 50 mobile homes: minimum 12.1 m long and 3 m wide; maximum 21.4 m by 7.3 m; height 4.5 m, 1 storey [1]
Temporary garden suite: Garden suite only by site-specific temporary use by-law under s.39 of the Planning Act, up to 20 years; one per lot, rear yard, maximum 4.6 m and 1 storey, footprint the lesser of 50 m² or 15% lot occupancy [1]

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. [11][6][3][8][7]

Bunkie or sleeping cabin

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

Not allowed · Cornwall’s term: “accessory building”

The by-law defines accessory buildings as not used for human habitation, and boathouses may not include a guest cabin; no sleeping cabin or bunkie use is provided for. [1]

Approvals: 'Accessory' building or structure is defined as one that 'is not used for human habitation' (s.2) [1]

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. [8][6][3][12]

Official links

Last confirmed October 2026.

Notes and caveats

December 2025 office consolidation (latest listed amendment By-law 2025-110, Housekeeping Amendment No. 3, Nov 10 2025). Cornwall is largely urban; rural lands are in Prime Agricultural and Rural Area zones where dwellings are only incidental to agriculture. No ARU guide page found on cornwall.ca.

Sources

Not legal advice

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