Can I build a laneway house on my property in Toronto?

How big can it be?

How much will it cost?

What's my return on investment?


Lack of Housing

Planning policies in many North American cities have led to an increase in demand for housing in and around major cities due to the predominance of low-density, single-family housing.  Recent changes to such policies now allow and prescribe (as per by-laws) the construction of a second dwelling on many properties with an existing house. This second residential dwelling is sometimes known as an accessory/ancillary/secondary dwelling unit, granny flat, or in the case of Toronto, a laneway house (LWH). Faced with increasing housing costs and restricted growth, Toronto homeowners would like to know if they can develop their properties to accommodate LWHs.

Dencity is an online tool that helps you determine whether you can build an as-of-right LWH (conforming to by-laws), how much it will cost, how much area you can build, and what the financial return may be. While not supplanting the expertise of professional consultants, this tool may help you establish an initial understanding of how you can develop your laneway property to accommodate another liveable space.


Dencity's calculations are based on City of Toronto open data files. Combined with zoning by-laws, these files establish key parameters that dictate your as-of-right laneway house's (LWH) design. 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. Any information garnered from the tool should be considered as preliminary planning information only. Costing resources include Hanscomb Yardsticks for Costing, RSMeans, and other online resources. Interested homeowners should always consult licensed professionals (architects, contractors, City planners, banking/mortgage representatives, etc.) and confirm with the City that the proposed LWH area does not exceed the gross floor area of their primary house before embarking on a laneway house project.

User Friendly

Dencity shows users the maximum allowable square footage they can build a 1 or a 2 storey as-of-right LWH. The app also uses the allowable building area to inform its costing tool. Once at the costing step, users may input their specific financial information to allow for greater flexibility in adjusting computation.


Quickly check if your property qualifies for an as-of-right laneway house (LWH) and how much it might cost. Note that even if Dencity lists a property as not being viable, the in situ reality may differ from the data sourced. Homeowners should check their property's viability by measuring and checking that LWH zoning criteria can be met. In addition, homeowners may apply to Committee of Adjustment for non-conforming LWHs that vary from the zoning by-law.


Automatically see how much area you can build your LWH in, visualized on your property, with options for 1 and 2 storey buildings.


Use Dencity's financial calculator to come up with a baseline to inform your construction budget and return on investment. City of Toronto LWH financial incentives have been incorporated.

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What is a Laneway House?

Planning policies featuring low-density, single-family housing in many North American cities have resulted in increased demand for housing in and around major cities. While recent high-density development has launched huge condominium growth in places like Toronto, land dedicated to single-family housing remains incredibly low in occupancy, with no 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 residential zones.

Seeing the need to fill in this missing middle ground, various North American municipalities, including Toronto, have granted homeowners the option to construct an accessory dwelling unit in their backyard. Standard Toronto houses typically have a backyard, street access at the front, and a lane at the rear. Properties with rear or side yard access to lanes are permitted to have these units, referred to as laneway houses (LWHs).

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 LWHs, 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 housing suites website (here) to acquaint themselves with official guidelines. A detailed explanation of Toronto's LWH zoning parameters follows below.

Show Zoning Criteria for Toronto ▼


No, the City does not currently allow severing of properties with laneway houses (LWHs). You could attempt to get approval through Committee of Adjustment, but this is a long and arduous process. The current LWH policies outline connected services (gas, plumbing, electricity, etc.) from the front of the site/main house, running to the LWH at the back. Severing makes this more difficult.
Yes, you may build a basement under your laneway house. 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 house 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 house (LWH) footprint might leave extra space at the rear boundary (maximum LWH depth is 10m). If you consider building a LWH, 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 house (LWH), cost of construction, and current primary home value may factor into the insurance increase. Not all insurers provide complete coverage for LWHs, 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 house (LWH). In terms of landscaping, the area between the primary house and the LWH needs to be minimum 60-85% soft landscaping (grass, bushes, etc.), and the area between the LWH and the lane is required to be minimum 75% soft landscaping, exclusive of any possible driveway to a LWH 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 house (LWH), and if so, the maximum footprint and area of the LWH. 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 LWH zoning criteria can be met. After confirming the property is viable for an as-of-right LWH, 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 LWH 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.

About Us

Rachel Cohen-Murison

Rachel Cohen-Murison

CEO | Founder

Rachel is an architect with many years of experience working in various architecture practices in Canada and abroad. She brings her knowledge of GIS mapping as well as Toronto residential planning and costing to Dencity.

Christoph Krettler

Christoph A. Krettler

CTO | Founder

Tapping into his data science skills, Christoph's ability to transform the applicable data files into components of a useful tool gives Dencity its formwork. When not working on mapping cities, Christoph applies his data expertise in the world of biotech.

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