Stone Mills zoning for small homes

Township of Stone Mills, in the County of Lennox and Addington. Population 7,826 (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 with limits · Stone Mills’s term: “second unit”

One second unit is permitted per lot in any zone that allows a main residential use, either in the single detached dwelling or in an accessory building, subject to road, servicing and size conditions. Ontario's Planning Act (s. 35.1) overrides zoning provisions that would prohibit one unit in a building ancillary to a house on serviced urban land. [1]

Maximum size: Accessory building containing a second unit max 100 m² (s.3.25 c) [2]
Number allowed: Maximum one second unit per lot (s.3.25 e) [2]
Setbacks: Must meet the zone's minimum yards for residential uses (s.3.25 c, s.3.1.2) [2]
Separation from house: Accessory buildings not closer than 1.5 m to the principal building (s.3.1.2 c) [2]
Servicing: Must front on a year-round publicly maintained road and show adequate potable water and septic capacity (s.3.25 g, i) [2]
Parking: Minimum one parking space per second unit (s.3.25 h) [2]
Maximum height: Accessory buildings max 7 m (s.3.1.3) [2]
Where allowed: Any zone that permits a principal residential use; not in a boathouse (s.3.25 a, d) [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. [1][3][4]

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 with limits · Stone Mills’s term: “single-detached dwelling”

The rural and residential zones set a minimum dwelling unit area of 60 m² (50 m² in the Residential Limited Service zone).

Minimum dwelling size: 60 m² in the PA, RU, RR and HR zones; 50 m² in the RLS zone (zone provisions for residential uses) [2]
Minimum lot size: 1 ha in PA, RU, RR, RLS and HR zones (may be reduced to 0.5 ha in RU, RR and HR with technical studies) [2]

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. [1][5][6][7][8][9][10]

Tiny home on wheels or park model

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

Not allowed · Stone Mills’s term: “trailer / recreational vehicle / mobile home”

A dwelling excludes trailers, motor homes and mobile homes, and no zone permits mobile homes; a travel trailer or RV may be lived in only temporarily during construction of a house under a building permit. Trailer parks and RV parks are permitted only in the Recreation Commercial (C3) zone, where recreational vehicles are defined for short-term recreational use.

Where allowed: Trailer park and recreational vehicle park are permitted uses in the C3 zone; recreational trailer dwelling unit area max 44 m² (s.4.13.6) [2]
Approvals: Travel trailer, tent trailer or RV may be occupied during construction of a dwelling with a valid building permit, max two years from permit issuance, with approved sewage connection (s.3.6 b) [2]

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. [10][5][1][7][6]

Bunkie or sleeping cabin

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

Allowed · Stone Mills’s term: “bunkie”

One bunkie (sleeping quarters with no kitchen, for family or temporary guests) is permitted as an accessory use to a single-detached dwelling in the Prime Agriculture, Rural, Rural Residential and Residential Limited Service zones.

Maximum size: 20 m² gross floor area (definition of Bunkie) [2]
Number allowed: One bunkie per lot [2]
Kitchen: No kitchen facilities; sanitary facilities require approval from the appropriate approval authority [2]
Where allowed: PA, RU, RR and RLS zones [2]
Setbacks: Bunkies must comply with the zone's minimum yards for residential uses (s.3.1.2 a) [2]
Maximum height: Accessory buildings max 7 m (s.3.1.3) [2]

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. [7][5][1][11]

Official links

Last confirmed October 2026.

Notes and caveats

The by-law still uses 'second unit' (one per lot, By-law 2018-909); no 'additional residential unit' amendment appears in the April 2026 consolidation, so provincial Planning Act rules on additional units may allow more than the by-law text. The Bunkie definition's zone column also lists HR, but the HR zone's accessory uses do not list a bunkie, so HR is not included. A separate 'Cabin (hunt camp, fishing camp)' rule (s.3.2) allows a cabin up to 60 m² on a vacant existing lot (no dwelling), 15 m from lot lines and 30 m from water. No ARU guide page found.

Sources

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