What is a Laneway House or ADU?

Planning policies featuring low-density, single-family housing in many Canadian cities have resulted in an increased demand for housing. While recent high-density development has spurred condominium growth, land dedicated to single-family housing remains inefficient in its use of space, with little foreseeable increase to middle- or high-density permitted in the future. Given the significant increase in housing prices, restricted growth, long commute times, as well as changing family and work needs, there is now a need to moderately increase density in low-rise single-family residential zones.

To address this missing middle, various Canadian municipalities like Toronto, Hamilton, Montreal, Halifax, Calgary, Vancouver, and Victoria, to name a few, have granted homeowners the option to construct a second as-of-right (as per by-law) dwelling in their backyard. Depending on the city, this dwelling can be called a secondary/ancillary/accessory dwelling unit (ADU), a laneway house/suite, or a garden suite. The rules for these dwellings vary by city, as outlined below.


Currently, Toronto's zoning by-laws allow for the construction of an as-of-right secondary dwelling unit in the rear yard of properties along a lane. Properties with rear or side yard access to lanes are permitted to have these units, referred to as laneway suites, or colloquially as laneway houses.

Toronto’s 2018 as-of-right housing by-law (810-2018) and subsequent 2019 amendment allow Torontonians to build as-of-right laneway housing in the city, which must abide by certain zoning criteria (below). The City encourages the development of laneway suites, as they help people live close to where they work, and keep lanes “green, liveable, and safe.” The City defines a laneway suite as a “self-contained residential unit, subordinate to a primary dwelling, in which both kitchen and bathroom facilities are provided and located on a lot within an ancillary building, adjacent to a public laneway. Laneway suites provide an additional form of contextually appropriate low-rise housing within the City’s neighbourhoods and are part of complete communities.” Interested homeowners are encouraged to explore the City of Toronto’s laneway suites website (here) to acquaint themselves with official guidelines. A detailed explanation of Toronto's laneway suite zoning parameters follows below.

Zoning Criteria

Emergency Access Option A

In order to access the laneway suite (LWS) in case of an emergency, Toronto Fire Services and Emergency Services require access from a public street to the entrance of the LWS that is maximum 45m long, and minimum 0.9 metre wide. This can be accommodated by a 0.9 metre wide side yard.

Emergency Access Option B

Access to the laneway suite (LWS) entrance can alternatively be provided via a maximum 45m long route running along a public street or public lane. The location of a LWS entrance is up to the individual once in design phase, but typically faces the existing house or the lane. For this reason, Dencity bases its distance to hydrants on the most conservative assumption: that the main entrance is located facing the lane.

Emergency Access Option C

If your laneway suite (LWS) entrance is beyond 45m, but below 90m, from the entrance to the public street or public lane, you may still construct a LWS, but it must be sprinklered.

Side Yard Setbacks

Minimum side yard setbacks are as follows:

  • For side lot line not abutting a street or lane, the minimum setback is 0 metres
  • For side lot line abutting a street, the minimum setback is to align with the existing house
  • For side lot line abutting a lane, the minimum setback is 1.5m

Width & Coverage

A laneway suite (LWS) may cover maximum 30% of the lot area. LWS area must not exceed the gross floor area of primary house (confirm with City). In addition, the property's rear lot line must be 3.5m minimum. The LWS's maximum width is 8 metres.


Tree by-laws prevent removal of any mature tree with a diameter exceeding 30 centimetres. Check your property for trees.

Emerg. Acc. Option A Detailed

If emergency access to your laneway suite is provided by a 0.9 metre minimum side yard, it must also be free of vertical encumbrances up to 2.1 metres minimum. Where there is no 0.9 metre minimum clearance to the side lot line, but there is 0.9 metre minimum clear to the face of a neighbour's house, a Limiting Distance Agreement may be signed, allowing the side yard to be considered valid for emergency access. Consult the City of Toronto (here) for more information

1 Storey

If constructing a 1 storey laneway suite, the maximum height is 4 metres, and it must be 5 metres minimum from the existing house. Maximum depth is 10 metres, with a 1.5 metre setback at the rear lot line.

2 Storey with 7.5m Setback

If constructing a 2 storey laneway suite (LWS), the maximum height is 6 metres, with anything falling within 9.5m from the existing house and above 4 metres to be chamfered with a 45 degree angle. The LWS must be 7.5 metres minimum from the existing house. Maximum depth is 10 metres, with a 1.5 metre setback at the rear lot line.

2 Storey with 9.5m Setback

For a 2 storey laneway suite (LWS) located 9.5 metres minimum from the existing house, the maximum height is 6 metres, and no chamfer is required. Maximum depth is 10 metres, with a 1.5 metre setback at the rear lot line.


No, the City does not currently allow severing of properties with laneway suites (LWSs). You could attempt to get approval through Committee of Adjustment, but this is a long and arduous process. The current LWS policies outline connected services (gas, plumbing, electricity, etc.) from the front of the site/main house, running to the LWS at the back. Severing makes this more difficult. There are examples of laneway houses on severed lots in the city, but these were typically established a while ago, before as-of-right laneway suite policy was enacted. This is why the City refers to the new dwellings on unsevered lots as "laneway suites" and not "laneway houses".
Yes, you may build a basement under your laneway suite. The area of the basement may be counted towards your total allowable building area under zoning by-laws, and as such, has not been factored into Dencity's area calculations. Confirm with a City zoning official and your design/architectural team during zoning review.
You can have a patio on the ground or second floor level, but without going to Committee of Adjustment, you are not permitted to have a patio on your roof.
Take the design to Committee of Adjustment with your design/architectural team and be prepared to spend a lot of time and money negotiating.
The zoning by-laws demand any part of a laneway suite that's over 4m high and within 7.5-9.5m from the face of the primary house be cut back at 45 degrees. This is because of shading, privacy, and possible fire safety reasons. To simplify our calculations, we therefore propose a 2 storey option that's the closest it can be to the primary house (7.5m), or a second option which does not require the chamfer, at 9.5m.
As a preliminary design tool, Dencity will show you the maximum amount of area you can build based off of setbacks from the primary house, maximizing area to the side yard boundary, then finally expanding backwards towards the rear setback. If your property is exceptionally deep, the proposed laneway suite (LWS) footprint might leave extra space at the rear boundary (maximum LWS depth is 10m). If you consider building a LWS, it's up to you and your design team to establish where you want to locate the building on your site and how big you'd like to build it.
This is hard to gauge without consulting with your insurer. Factors like credit score, the number of tenants in the laneway suite (LWS), cost of construction, and current primary home value may factor into the insurance increase. Not all insurers provide complete coverage for LWSs, and sometimes separate insurance must be obtained. Contact your insurance provider for more details.
You may, but you should contact the City for further requirements.
You're required to provide 2 bicycle parking spots for your laneway suite (LWS). In terms of landscaping, the area between the primary house and the LWS needs to be minimum 60-85% soft landscaping (grass, bushes, etc.), and the area between the LWS and the lane is required to be minimum 75% soft landscaping, exclusive of any possible driveway to a LWS garage.
Dencity provides preliminary planning and costing information to users based on open data from the City of Toronto. Compiled with zoning by-laws, these files establish key parameters that dictate if your property is viable to accommodate an as-of-right laneway suite (LWS), and if so, the maximum footprint and area of the LWS. Dencity is as accurate as the files it pulls information from, and discrepancies resulting in inaccuracies or variations from the in situ reality of any given property should be understood through this lens. Homeowners should check their property's viability by measuring the property and checking that LWS zoning criteria can be met. After confirming the property is viable for an as-of-right LWS, homeowners are encouraged to consult an architect to develop an application for zoning review with the City. Should a property prove to not be viable for a LWS as per current zoning by-laws, homeowners may still apply to Committee of Adjustment, but it is highly encouraged to first discuss non-conforming situations with one's architect as higher costs, an extended schedule, and more iterative negotiations with the municipal approvals team will be needed.
In development. Check back later!
In development. Check back later!