Some parts of this guide may not accurately reflect recent changes to land use planning rules introduced under the More Homes Built Faster Act, 2022. We are working to update the guide to include these changes.
Disclaimer: This document is provided for convenience only and should not be relied upon as a substitute for construction, engineering, architectural or legal advice. The Ministry of Municipal Affairs and Housing does not assume responsibility for errors or oversights resulting from use of this document.
Introduction
Definition of a laneway house
Is your property connected to a laneway? Have you ever thought of how you could provide living space for family or generate more income from your property? Have you considered building a laneway house? Laneway housing might be the innovative housing solution for you.
A laneway house can:
- provide rental income to property owners
- provide housing for grown children, parents or in-laws
- take advantage of existing infrastructure
- add residential units into neighbourhoods
- help vitalize underused laneways into safer, more vibrant public spaces
A laneway house, often referred to as a laneway suite, is a residential unit that is separate from a primary residence and is typically located in the rear yard of a property, connected to a public laneway. While most commonly found in urban areas, laneway houses can also exist in rural settings.
There is a lot to consider before building a laneway house. This guide covers key provincial and municipal rules and requirements regarding laneway houses. It will help you learn more about how to:
- build a new laneway house
- renovate an existing building (such as a garage or coach house) to create a laneway house
These rules and regulations (including the provincial ones) are enforced and implemented by municipalities. It is important that you talk to your municipality early and often as you design and build your laneway house.
You may also want to consider reading the ministry’s other guides, Build or buy a tiny home and Adding a second unit to your existing house, before deciding which housing choice best suits your needs. Some of these options overlap – in fact, a tiny home could be a laneway house if it is connected to a laneway. There are some rules and requirements that are specific to laneway houses, and before you go any further, you should ask yourself the following questions to determine whether to proceed or perhaps consider a different housing option for your property:
Flow-chart with four questions. If the answer is no to any of these questions, you will likely not be able to build a laneway house.
While this guide contains a lot of important information, other considerations, such as tax implications, financing and how to hire professionals are not covered in this guide.
The sections that follow will highlight key rules and requirements. Some of these rules are made by the provincial government and some are made by local municipalities. Regardless, the requirements discussed in this guide, even the ones made by the provincial government, are enforced and implemented by municipalities. As a result, it is important that you talk to your municipality early and often as you navigate through your laneway house project.
The provincial role
Ontario supports and encourages construction on laneway housing to help create much-needed housing especially in urban centres.
Through the Building Code Act and the Building Code, the province sets out uniform building standards for all of Ontario, including those regarding laneway housing. Municipalities have the responsibility to administer and enforce the Building Code within their own jurisdictions.
The Ontario Planning Act authorizes municipalities to pass zoning by-laws that allow them to determine land uses including supply and type of residential land within their jurisdictions.
The Act was changed in 2019 to require municipalities to adopt official plan policies and pass zoning by-laws that allow one additional residential unit in the primary residence and one in an existing or new building or structure ancillary to the primary residence. This change was designed to help increase the supply of housing and create more options for families.
Additional changes were made under the Planning Act in Ontario Regulation 299/19 that removes certain zoning barriers to the creation of additional residential units and sets the following standards and requirements:
- one parking space per additional residential unit, with municipal by-laws prevailing where municipal parking standards are lower
- a parking space for the use of the occupant of an additional residential unit may be a tandem parking space
- occupancy of additional residential units is permitted regardless of who occupies the primary residential unit, and
- where the use of additional residential units is authorized, an additional residential unit is permitted regardless of the date of construction of the primary residential unit.
This illustration shows examples of the range of additional residential units (also referred to as secondary detached dwelling units in some municipalities). You can see that the main difference between a laneway house and these other innovative housing options is that the laneway house abuts a laneway.
Diagram 1: Aerial view of laneway housing
Diagram 2: Aerial view of additional residential units/range of housing options
The municipal role
Laneway housing offers municipalities another way to create additional housing on individual residential properties that meet the new Planning Act’s requirement that allows up to two additional residential units on a residential property.
Many municipalities allow laneway housing. If you are considering building a laneway house, it is critical that you check local rules, including official plan policies, zoning by-laws and permit requirements, and any other applicable municipal by-laws for your property. Your municipality may use other terms in these documents, including laneway suites, tiny homes, coach houses, secondary dwelling units, accessory dwelling units or additional residential units.
Municipal rules and requirements
It is important to know your municipality’s zoning by-laws. They set the rules that allow the use of a laneway house and will help you determine whether your lot is suitable. Ask your local planning and building department about:
- zoning requirements and standards for laneway housing that apply to your property
- any other applicable agreements and approvals that are required before you can build a laneway house
- if your laneway house is planned for rental, whether you will be required to license or register it with your municipality
Garden suites
Garden suites are another form of housing you may wish to consider as an option for adding an additional dwelling unit on your property. Garden suites are similar to laneway houses except that they are located on properties that are not connected to a laneway.
Garden suites would need to meet many of the same planning, Building Code and Fire Code requirements as laneway houses. This includes municipal zoning and servicing requirements, and health and safety standards in the Building Code.
A key difference between garden suites and laneway houses is likely to be the type of lots they would be built on. In the older parts of urban downtown areas that were built in the late 1800s and early 1900s throughout the province, many lots tended to be long and narrow. On these lots it was typical that the house facing the street would be nearly as wide as the lot itself with only a few feet separating houses on adjacent lots. As a result, these older urban areas were developed with rear lanes to provide access to the back of the property. During the 1920s and later, municipal lot layouts began to change. Properties became less long and narrow and took on a squarer shape. This layout allowed for greater side-yards between the house and the side lot lines. Driveways and garages became the norm in order to accommodate growing automobile ownership.
Under current provincial and municipal planning rules, properties as described above are also able to add an additional residential unit. These buildings would typically be accessed via the driveway or a pathway in a side-yard. This extra space on a lot for a driveway or a side-yard means that garden suites may not face as many of the same obstacles as laneway houses. In particular, some of the emergency access requirements may be more easily met on these squarer-shaped lots. This important difference may mean that over time, garden suites will become a popular choice for additional housing supply.
Although there are many similarities between garden suites and laneway houses, they are distinct from one another and your municipality may have different requirements in place for garden suites. Make sure you speak to your local building and planning department early on to determine which housing options could apply to your property.
Zoning
Zoning requirements and standards that could affect your plans to build a laneway house may include:
- permitted land uses
- requirements for lots connected to a public laneway
- minimum lot sizes
- minimum sizes and maximum heights for residential buildings
- minimum or maximum lot coverage by built structures
- lot length, lot width and setback
- massing (height and size)
- parking
- building character
- tree protection
If your property does not comply with your municipality’s by-laws, you may not be able to build a laneway house on your property unless you successfully obtain a zoning by-law amendment or minor variance.
Zoning requirements will vary from municipality to municipality. Not all municipalities have zoning by-laws related to laneway housing, though there has been an increase in those that do allow this type of housing in the last few years. Two examples of laneway housing zoning by-laws below illustrate this.
Ottawa
Ottawa changed its zoning by-law in 2017 to permit coach houses.
The City’s by-law defines a coach house and contains detailed performance standards that also apply to laneway houses.
If you live in Ottawa and would like to add an additional residential unit that is detached from your principal dwelling, check the City’s Official Plan and zoning by-law for important requirements and restrictions, such as water and sewage system servicing, location, maximum size and height of the coach or laneway house and parking. You can also find more information online.
Kitchener
The City of Kitchener’s municipal council approved a by-law change in April 2021 that will allow tiny homes to be built in backyards on some properties in residential zones, as well as coach and laneway houses, among other additional residential units. Some of the zoning regulations include specification of the size of the unit, setbacks, building height, location on the lot, lot width and lot area.
These examples show how zoning by-laws are applied differently in various municipalities. For information on your municipality’s zoning and other by-laws, please contact your local building and planning department.
If you can’t meet some of the zoning by-laws
Two of the most common ways you can seek to change the zoning requirements on your property are through a “zoning by-law amendment” (also known as a rezoning) or a “minor variance”.
Zoning by-law amendment/rezoning
A rezoning is generally needed when you want to use or develop your property in a way that is not permitted by the existing zoning by-law. A rezoning is required when you propose to change some basic rules about how your property is used. A rezoning is also often needed when you want to make a fairly major change to the zoning by-law, such as adding another use (for example, adding a store or an office) on your property or significantly altering the proposed size, height and location of a building from what the rules currently allow. A rezoning application is decided by the council of the municipality.
Minor variance
A minor variance is needed when you propose to build something that does not conform to the zoning requirements. It is used for changes that are minor in nature and meet the general intent of the official plan and the zoning by-law, for example, if you plan to locate part of your laneway house slightly closer to a property line than the zoning setback requires. A minor variance is generally decided by the Committee of Adjustment of a municipality.
You will generally need to submit an application to your municipality to change specific rules that apply to your property along with the specified fee. You should contact your local planning department to assist you in determining whether you should apply for a rezoning or a minor variance.
As part of both the rezoning and minor variance processes, your neighbours will receive a notice from your municipality informing them of your proposed changes. They can comment on any of these changes in writing and at public meetings. They also have the right to appeal any decisions made about your application.
You should always speak to planning staff in your municipality before submitting an application to determine whether the city staff will support it and to get advice and information. You may also wish to seek the help of a professional planner.
Servicing and access
Your laneway house will need access to services (for example, water, hydro, sewage, garbage collection). You will need to speak to your municipality to determine whether you will be allowed to:
- service your laneway house through the primary house
- provide separate services to your laneway house
Some municipalities may have concerns about whether there is sufficient water and sewage capacity to allow new development in a particular area. Your municipality will likely have rules about water and sewage servicing and whether you can connect to the existing ones.
If you plan to sell an existing or newly built laneway house separately from the primary house, you will likely need a lot severance. Most municipalities will not approve an application for a lot severance on a laneway on the basis of servicing. Proceed carefully and contact your local planning department first if it is your plan to sell your laneway house.
Unless your property is on a corner lot, an important feature your laneway house will need is a path from the laneway house to the street in front of the primary residence. This will give laneway house occupants easy access to the street to do such things as put out garbage and recycling, which municipalities generally do not collect from laneways. This pathway is also vitally important to allow emergency responders adequate access to the laneway house.
Provision for emergency access
An important safety aspect of a laneway house is providing access to it if there is a fire or medical emergency. Firefighters with portable equipment and Emergency Medical Service (EMS) personnel with a stretcher or gurney need to be able to access all dwelling units. To provide this access, municipalities typically require an unobstructed path or route. Some municipalities rely on their local fire departments to determine access requirements so that firefighting needs are met. Finding out your municipality’s emergency access requirements is something you must do early on as you consider building a new laneway house or renovating your existing building.
In addition, the Building Code has access requirements for firefighting vehicles, including fire trucks. The Building Code requires that each building have access for fire department vehicles by a public street, a private road, or a yard. Private roads or yards are only acceptable as a means of fire service access if certain conditions are met, such as connection to a public thoroughfare, and overhead clearance. A fire hydrant must also be located within 90 metres of where a firefighting vehicle would park at the subject property containing the laneway (for example, in front of the primary residence). Typically, the standard length of a fire hose is 45 metres, so you would measure 45 metres from the fire hydrant to the pumper truck, then 45 metres from the pumper truck to the laneway house. The diagram below gives a visual representation of fire truck access to a laneway house and to a fire hydrant from a main street.
Firefighters may also use laneways if they are at least 6 metres wide, but there is greater risk of damage to equipment and inadequate access to a fire hydrant than when emergency access is provided via the main street.
It is very important that you determine early on in your project planning that your laneway house will be able to meet these requirements for emergency access, because if it cannot, you will likely not be able to build your laneway house.
Relevant Building Code provision: Division B, Articles 9.10.20.3. and 3.2.5.7.
Diagram 3: Provision for emergency access
Building Code
Getting a building permit
Whether you are building a laneway house from the ground up or renovating an existing building, you will need a building permit.
You or your agent (for example, a qualified designer, engineer or architect) can apply for a permit at your local building department. You will need to submit:
- a completed application form and any other forms and supporting documents requested by the municipality
- construction drawings (most municipalities require at least two sets of drawings)
- payment of the building permit fee
You can search your municipality’s website for building permit and building by-law information to see if there are additional forms and application requirements.
You should also check with your municipality to find out if:
- you need to hire a licensed contractor to do the work
- your project will require a builder registered with the Home Construction Regulatory Authority
- they accept electronic building permit applications, as this could speed up processing time
You will need to demonstrate that your project meets the technical requirements of the Building Code as well as other “applicable laws” listed in the Building Code. An example of applicable law is a municipal zoning by-law.
If you have not met local zoning requirements, you will not be able to get a building permit.
Incomplete applications or improper design may mean your building permit will be delayed or denied.
Once your complete application has been submitted, you can expect to hear back within 10 business days if it has been approved or not.
Although homeowners can design and build their laneway houses themselves, we recommend you hire at least one of the following to help you through the sometimes-complex approval and building process:
- Building Code designer registered with the Ontario government
- professional planner
- architect
- professional engineer
- licensed technologist (Ontario Association of Architects) or licensed engineering technologist (LET)
These professionals and your builder can help you get all the necessary approvals, building permits and arrange for construction inspections.
Building inspections
After your building permit has been issued and construction has begun, municipal building inspectors must review the work at various stages during construction.
Inspectors will need to check framing, insulation, foundations, service connections, plumbing, occupancy, heating, and other items contained in the Building Code, as well as fire safety requirements. Confirm with your inspector about what needs to be inspected.
You or your contractor are responsible for informing your building department when different stages of construction are ready for inspection.
Building Code requirements for new construction and renovations
Ontario’s Building Code sets out minimum construction standards for how to build a new laneway house or renovate an existing building to create a laneway house. Some of these minimum standards are described in this guide.
Some Building Code requirements will vary depending on whether you are renovating an existing building or constructing a new laneway house from the ground up. The sections that follow provide information on Building Code requirements that apply to laneway houses generally and will distinguish when there are differences between renovating an existing building and building a new laneway house. Though some of this information is fairly technical, it should broaden your understanding of the Building Code and its requirements, and support you in your discussions with your agent and any professional you hire to help with your laneway house.
Advantages of building beyond the Code
In some cases, you may wish to build beyond the minimum requirements of the Building Code. This is especially recommended when converting an existing building, like a garage, into a livable space.
While you may not have needed things like heating or insulation in your garage, these and other energy efficiency considerations are important and required in a laneway house for the health and comfort of those living in it. For example, your renovated laneway house will require sufficient insulation and heating to maintain a liveable indoor temperature.
The Building Code also includes provisions relating to installing sufficient insulation and heating to maintain an indoor temperature of 22 degrees Celsius during winter (see Article 6.2.1.2. in Division B and the Code’s Supplementary Standard SB-12 “Energy Efficiency for Housing”). By installing adequate insulation and heating, you can prevent rot and mold in your laneway house, reduce heating costs, and do your part to protect the environment. See further details on energy efficiency in laneway houses.
Whether you are renovating an existing building or creating a new laneway house, building beyond the Building Code provides homeowners many advantages, including greater occupant comfort and amenities that can make your laneway house a nicer place to live.
Age of building
If you are renovating an existing building into a laneway house, be aware that different Building Code rules apply depending on the age of your building.
If it is more than five years old, it is classified as an existing building and you may have more flexibility under the Building Code when you make renovations.
If it is less than five years old, then it is classified as a new building and under the Building Code it generally must meet new construction requirements. For more information on how this applies to your situation, contact your designer or local building department. Keep this in mind as you read this section further and pay closer attention to any Building Code requirements that are specific to “new construction.”
Stairs, guards and handrails
Designing a laneway house with more than one storey means you will need stairs. Ladders to a second storey do not comply with Building Code requirements.
Different Building Code requirements apply for regular private stairs and stairs that serve a mezzanine (for example, a loft) in a laneway house that is used as a live/work unit. See Table 1 below for details on rise, run and tread depth for rectangular treads.
| Stair type | All steps - Rise | Rectangular treads - Run | Rectangular treads - Tread depth |
|---|---|---|---|
| Mezzanines in live/work units | Maximum: No limit; Minimum: 125 mm | Maximum: 355 mm; Minimum: No limit | Maximum: 355 mm; Minimum: No limit |
| Other private stairs | Maximum: 200 mm; Minimum: 125 mm | Maximum: 355 mm; Minimum: 210 mm | Maximum: 355 mm; Minimum: 235 mm |
Additionally, stairs are required to have guards and handrails.
Be sure to check with your designer or local building department to understand the requirements for stairs, guards and handrails in laneway houses.
Relevant Building Code provisions: Division B, Subsections 9.8.3. and 9.8.4.
Good to know
Building Code requirements for stairs will change on January 1, 2022. This guide will be updated once the changes take effect. If you applied for a building permit that includes construction of stairs in your laneway house before January 1, 2022, you will not have to modify the stairs to meet the new requirements.
Mezzanines
Instead of building a full second storey in your laneway house, another option is to build a loft or a partial second floor. The Building Code calls these spaces “mezzanines.” In a laneway house these spaces would consist of a raised floor area and are often intended as a sleeping space.
Here are some of the Building Code rules for mezzanines:
- if the mezzanine is open to the floor below, then the size of the mezzanine cannot be greater than 40% of the floor area of the laneway house it opens into, and it must have a guard/handrail to prevent falls
- if the mezzanine has walls higher than 1,070 mm all around it, then it is considered a “closed mezzanine” and it cannot be greater than 10% of the laneway house
- mezzanine must have stairs, guards and handrails that meet the Building Code
- there are also requirements for minimum ceiling heights
Relevant Building Code provisions: Division B, Article 9.10.4.1.
Room sizes and floor areas
The Building Code sets out minimum room sizes in dwelling units. Room sizes do not vary whether you are building a new laneway house or renovating an existing building, but they do vary depending on whether the rooms and spaces are separated by walls or if the unit is open-concept. Total floor areas of rooms/spaces can be smaller when using an open-concept design.
For example, a laneway house with an open-concept design can be as small as 17.5 m2. See Table 2 for an example of open-concept minimum space requirements.
| Room or space | Minimum required floor area |
|---|---|
| Combined sleeping, living and dining areas and kitchen space | 13.5 m2 (145 ft2) |
| Bathroom | Enough space for sink, toilet and shower stall or bath. Could be as little as 3.0 m2 (32 ft2) |
| Laundry | 1.0 m2 (11 ft2) |
Table 3 outlines the general minimum sizes for rooms and spaces separated by walls.
| Room or space | Minimum required floor area |
|---|---|
| Living area | 13.5 m2 (145 ft2) |
| Dining area | 7.0 m2 (75 ft2) |
| Kitchen | 4.2 m2 (45.2 ft2) |
| Combined living, dining and kitchen areas in a one-bedroom unit (2 persons) | 11 m2 (118.4 ft2) |
| Master bedroom (without built-in closet) | 9.8 m2 (105.5 ft2) |
| Other bedrooms (without built-in closets) | 7 m2 (75 ft2) |
| Bathroom | Enough space for a sink, toilet and shower stall or bath |
Relevant Building Code provisions: Division B, Subsections 9.5.4. to 9.5.9. and 9.31.4.2.
The following diagram demonstrates how to measure the floor area of a room.
Diagram 4: Measurements of minimum floor area
Ceiling heights
You are required to meet minimum ceiling heights in your rooms, though you can choose to exceed the minimum ceiling heights throughout your laneway house. The Building Code minimum ceiling height requirements are shown in Table 4. These requirements only apply to new construction, including live/work units.
| Room or space | Minimum heights |
|---|---|
| Living room or space, dining room or space, kitchen or kitchen space | 2,300 mm (7’6.5”) over at least 75% of the required floor area with a clear height of 2100 mm (6’10.5”) at any point over the required area |
| Bedroom or bedroom space | 2,300 mm (7’6.5”) over at least 50% of the required area or 2,100 mm (6’10.5”) over all the required floor area. Any part of the floor having a clear height of less than 1400 mm (4’7”) shall not be considered in calculating the required floor area |
| Mezzanine | 2,100 mm (6’10.5”) above and below a mezzanine |
| Bathroom, water closet room or laundry area above grade | 2,100 mm (6’10.5”) in any area where a person would normally be in a standing position |
| Passage, hall or main entrance vestibule and finished rooms not specifically mentioned above | 2,100 mm (6’10.5”) |
If you are renovating an existing building, note that a laneway house with spaces under a sloped ceiling meets the Building Code if at least 50% of the required floor area has a ceiling height of 2.03 m (6’8”), but this does not include areas with low ceilings less than 1.4 m (4’7”) high. As well, any part of the floor area that is used as a way to get out must have a ceiling height of 1.95 m (6’5”).
Relevant Building Code provisions: Division B, Articles 9.5.3.1. and 9.5.3.2. and Table 11.5.1.1.C., Compliance Alternative 102
Hallway widths
The Building Code requires most hallways in new houses to be 860 mm (2’10”) wide. Some laneway houses may not have hallways because they will be open concept. An 860 mm (2’10”) wide hallway would only be needed if a laneway house has spaces, such as a living room and bedroom, separated by a hallway with walls on both sides.
A hallway can be 710 mm (2’4”) wide if it leads to a bedroom or bathroom. If this is the case, these rooms must be served by a separate exit door.
These requirements also apply to a renovation.
Relevant Building Code provisions: Division B, Subsection 9.5.10.
Door width
The exterior door of a new laneway house must be at least 810 mm (2’8”) wide and be a swing-type door (not sliding).
Bathrooms must have doors at least 610 mm (24”) wide. These can be folding, swinging-type or sliding doors. When renovating an existing building, existing doors are generally acceptable.
Relevant Building Code provision: Division B, Article 9.5.11.1.
Windows
Windows are required in laneway houses. The size of windows you need is determined by the size of the unit. Larger units will require more or bigger windows. Window sizes are also based on what type of room they are in and they will vary depending on whether your laneway house is a new building or if you are renovating an existing building. The minimum window sizes in each scenario are shown in Table 5:
| Room or space | Minimum required window area for a new building | Minimum required window area for an existing building |
|---|---|---|
| Living room or dining room | 10% of the floor area | 5% of the floor area |
| Bedrooms | 5% of the floor area | 2.5% of the floor area |
| Work area in live/work unit | 10% of the floor area | 5% of the floor area |
Relevant Building Code provisions: Division B, Article 9.7.2.3. and Table 11.5.1.1.C., Compliance Alternatives C107 and C79
For example, if you are planning to have a dining area of 4 m2 (43.1 ft2) in a newly built laneway house, the minimum size of the window(s) must be 0.4 m2 (4.3 ft2). Diagrams 5 and 6 below show other examples.
Diagram 5: Minimum window area in a newly built laneway house
Diagram 6: Minimum window area in an existing building
The Building Code also contains requirements for the maximum area of glass or glazed unprotected openings, which includes windows, and this largely depends on the laneway house’s distance to a lot line, the centerline of the street or to an existing residence. Fire safety measures for exterior walls elaborates on this requirement and provides various scenarios.
In addition to these Building Code requirements, your municipality may also have requirements for windows to protect your or your neighbours’ privacy.
Plumbing
Your new or renovated laneway house will have to meet plumbing requirements. Apart from providing access to laundry appliances for new construction, there are no differences in the Building Code’s plumbing requirements between renovation work and new construction. At minimum you will need:
- a hot and cold water supply
- a sink, bathtub or shower, toilet, or a drainless composting toilet in the bathroom
- a kitchen sink
You will need a qualified plumber to do this work. Some municipalities require plumbers to be licensed.
Relevant Building Code provisions: Division B, Articles 9.31.4.1. to 9.31.4.3.
Because laneway houses are typically serviced by the primary residence, it must also have its own water shut-off valves. This allows plumbing work or repairs to be done in one unit without affecting water flow in the other.
Relevant Building Code provisions: Division B, Sentences 7.6.1.4.(1) and 7.6.1.6.(1)
If your property is in an area that is subject to flooding or sewer backup, you may need to install a backwater valve when you add a laneway house that has a basement. Backwater valves help prevent sewage in municipal drain pipes from entering floor drains and plumbing fixtures in the lower levels of your house.
Relevant Building Code provisions: Division B, Article 7.4.6.4.
Energy efficiency
Your new laneway house will have to meet the energy efficiency requirements in the Building Code. This means that the exterior walls will have to be designed with the right amount of insulation and be able to keep moisture and drafts outside of your home.
There are different energy efficiency requirements depending on where you live in Ontario. For example, if you live in northern Ontario your home will require more insulation.
We recommend that you work with an expert designer who knows these requirements.
You or your designer may also refer to the Energy Efficiency Design Summary (EEDS), if available in your municipality.
Relevant Building Code provisions: Division B, Article 6.2.1.2. and 9.25.2.1.
Heating and ventilation
New and renovated laneway houses must have heating, ventilation and air conditioning (HVAC) that conforms with the Building Code. Your laneway house will likely have much less space to heat and cool. A typical furnace for a regular size house may be too large. If this is the case, you may want to consider alternatives, such as:
- a ductless split system
- a baseboard heating system
- radiant floor heating
The Building Code has several different ways to meet the overall insulation levels and HVAC requirements. The two main methods for small residential buildings, such as houses and laneway houses are called the prescriptive method and the performance method. If you choose the prescriptive method, your laneway house will need a Heat Recovery Ventilator (HRV). An HRV exchanges air between the inside and the outside of the building. HRVs reduce energy demand and increase energy efficiency by recovering heat or conditioned air. An HRV is optional if you choose the performance method.
If your laneway house is being used as a live/work unit, other ventilation requirements may apply.
You should consider getting help from a professional in designing the HVAC system for your laneway house.
Relevant Building Code provisions: Division B, Sections 9.32. and 9.33.
Ventilation is also required for the bathroom and kitchen of your laneway house. This can be provided by a ceiling exhaust fan or a window that opens to the outside. If the laneway house contains an HRV, this will also provide ventilation.
Relevant Building Code provisions: Division B, Article 9.32.1.2. and Table 11.5.1.1.C., Compliance Alternative 194
Electrical facilities and lighting
The Building Code contains limited requirements for electrical facilities and lighting. The Electrical Safety Code, produced by Ontario’s Electrical Safety Authority, is where to look for most of the electrical requirements when building a new laneway house or renovating an existing building to create a laneway house.
The electrical requirements in the Building Code are specific to lighting levels and placement of lights and switches. Building Code requirements for adequate lighting are the same whether you are building a new laneway house or renovating an existing building to create a laneway house.
Minimum lighting requirements
You must have:
- a light at the entrance to your laneway house
- a light and switch in every room and space of your laneway house
- a switch at both the top and bottom of the stairs (if applicable)
Relevant Building Code provisions: Division B, Articles 9.34.2.1., 9.34.2.2. and 9.34.2.3.
You will need to get a separate electrical permit to do the electrical work in your new or renovated laneway house and Ontario’s Electrical Safety Authority (ESA) will need to inspect the electrical work.
We recommend that you hire a licensed electrical contractor to do the work.
They can also get the electrical permit and arrange inspections for you.
For further information you can contact ESA directly at
Foundation, anchorage and grading
This section mostly applies to the construction of a new laneway house.
Like a regular house, a laneway house must be attached securely to the ground. The Building Code has detailed requirements for footings and foundations. A laneway house can also be placed on an engineered concrete slab on the ground.
The Building Code also requires that the land on your property be graded so that it slopes away from your laneway house. This is to help keep surface water out of your house and reduce damage in case of flooding.
This is important whether or not the laneway house is new.
Additionally, your water runoff should be managed so that it does not adversely affect neighbouring properties.
Relevant Building Code provision: Division B, Section 9.15. and Article 9.14.6.1.
As well, some municipalities require a grading plan prepared by a qualified professional as part of the building permit application.
Fire separations
A fire separation acts as a physical barrier to slow the spread of fire from one part of the house to the other. Fire separations must be continuous in order to work properly and include protected openings if necessary (for example, fire dampers).
A fire separation can be a floor, wall, door with a self-closing device and a latch, or a combination of those things. It can be built using typical building materials, such as lumber and drywall.
Fire separations are built with differing levels, or ratings, of fire resistance. Fire resistance is measured by how long it would take a fire to burn through a fire separation spreading fire from one space, or compartment, to another. Fire separations in a small residential building typically have 30-minute, 45-minute or 60-minute ratings.
Fire separations can be vertical, if needed to separate two spaces that are side-by-side, or horizontal if the spaces are on top of each other. Typically, if your laneway house contains a garage, you will need an effective gas barrier between it and the rest of the house.
Relevant Building Code provisions: Division B, Articles 9.10.9.11., 9.10.9.14. and Sentence 9.10.9.16.(3)
Diagram 7: Typical wall that would generally achieve a 30-minute fire separation
Diagram 8: Typical floor/ceiling that would generally achieve a 30-minute fire separation
Fire safety measures for exterior walls
The distance between a laneway house and lot lines or neighbouring buildings determines options for the construction of the exposing building face of a laneway house. This distance is called a limiting distance. The shorter the limiting distance is (that is, the closer the laneway house is to a property line or a building on an adjacent property), the more stringent the fire safety measures become.
Generally, a laneway house that is:
- 1.2 m or more from the lot line does not require its exterior wall to be built as a fire separation
- less than 1.2 m but more than 600 mm requires a wall to have a 45-minute rated fire separation
- less than 600 mm requires a wall with a 45-minute rated fire separation and the exterior cladding must be non-combustible
If your laneway house is less than 600 mm from the lot line, you should consult with your local municipality to find out if there are other options to ensure fire safety.
This applies to both renovation and new construction.
Relevant Building Code provisions: Division B, Article 9.10.15.5.
Similar to a regular house, a laneway house’s proximity to lot lines and other buildings determines how much glass you can use for windows and exterior doors. In some cases, a window as a means of escape may be required, so it is important to know where you can put this window to meet all applicable Building Code requirements.
The Building Code sets out the maximum area of glass or glazed openings (for example, windows, doors) by percentage of the exposing building face area based on the limiting distance (such as the distance between the laneway house and the lot line or street line) and total area of the exposing building face. Simply put, the closer the walls of your laneway house are to a property line, the centerline of the laneway and/or another building (including the primary building on the same lot) the smaller the area for windows and doors with glass panels. The farther away it is, the larger these glass areas can be. Below are several scenarios for new construction.
If the maximum total area of the exposing building face is 10 m2 and:
- the limiting distance is less than 1.2 m, there can be no glass or glazed openings on that exterior wall
- the limiting distance is 1.2 m, 8% of the exposing building face area can be glazed
- the limiting distance is 2.5 m, 33% of the exposing building face area can be glazed
- the limiting distance is 4 m, 96% of the exposing building face area can be glazed
If the maximum total area of the exposing building face is 20 m2 and:
- the limiting distance is less than 1.2 m, there can be no glass on that exterior wall
- the limiting distance is 1.2 m, 8% of the exposing building face area can be glazed
- the limiting distance is 2.5 m, 21% of the exposing building face area can be glazed
- the limiting distance is 4 m, 53% of the exposing building face area can be glazed
In the case of an existing building, the Building Code allows existing windows to be relocated to another part of the wall in order to achieve an acceptable glass area for that wall.
If the lane behind a laneway house is on the lot line, the limiting distance for the exposing building facing the lane can be calculated from the center of the lane.
Speak to your municipal building department early on in the design process to confirm how these fire safety provisions apply to your situation.
Relevant Building Code provisions: Division B, Article 9.10.15.4. and Table 11.5.1.1.C., Compliance Alternative C172
Diagram 9: Measuring glazed opening
Exits
Getting out of a building quickly in an emergency is another important element of life safety. Different Building Code requirements for exits apply to different types of uses, layouts or designs of your laneway house.
In the simplest case, your laneway house only has one use in the entire building and there are no other spaces, such as a garage or workspace (that is, the whole house is lived in as one unit). In this case, similar to a regular house, an exit door direct to the exterior is required. If it is a two-storey building, the Building Code requires a second exit to provide a separate means of escape in an emergency, such as a window – see below for further detail.
There is a wide range of possibilities in the design of laneway houses. You could have different uses for different parts of the house. For example, a laneway house could contain a residential suite on a second storey and an office space or garage on the ground floor. In this case, each suite should have access to its own separate exit door. If this is not possible, and the two (or more) suites have a shared exit door through an exit stair or corridor, then there must also be a second means of egress for each of the suites, either through another door or through a window.
A window can be used as a second way to exit instead of a door if it:
- can be opened from the inside
- does not need a tool, key or special knowledge to open
- will stay open on its own without supports or levers
- has a clear opening of 0.35 m2 (3.8 ft2)
- is not smaller than 380 mm (15”) measured in any direction
- has a window sill not higher than 1 m (39.5”) above the floor
Diagram 10 below demonstrates an example of an escape window for an upper floor.
Diagram 10: Escape window for upper floors
In a live/work unit on a mezzanine, the Building Code does not require an escape window on the mezzanine level as long as:
- an escape window is provided on the ground floor
- the mezzanine is not more than 25% of the area of the laneway house or 20 m2, whichever is less
- there are no obstructions more than 1,070 mm above the floor and
- there is an unobstructed direct path of travel from the mezzanine to the window.
Relevant Building Code provisions: Division B, Sentences 9.9.10.1.(1) and 9.9.10.1.(4)
You should also check with your municipality whether you need to comply with any additional health and safety requirements.
Smoke alarms
You will need smoke alarms (sometimes known as smoke detectors) in your laneway house that meet the Canadian CAN/ULC S531 standard. A label on the alarm will indicate whether it meets this standard. Smoke alarms are widely available at hardware and home renovation stores.
Your smoke alarms must be interconnected with all other smoke alarms within the laneway house, and must:
- have a flashing light when they are activated, and
- be connected to an electrical circuit with no disconnect switch between the circuit and smoke alarm(s)
Proper placement of smoke alarms is important. They must be located:
- on every level of the building (if adding a second storey)
- outside of sleeping areas (depending on the layout of a floor, it can also count as the smoke alarm for that level)
- in each bedroom (if more than one and not open-concept)
Relevant Building Code provisions: Division B, Subsection 9.10.19.
Carbon monoxide alarms
You may also have to install carbon monoxide alarms. They are required if your laneway house has an appliance (for example, furnace, water heater or boiler) that uses natural gas, propane, other similar fuels or a wood burning appliance. Carbon monoxide alarms may also be required if your laneway house contains a garage.
Carbon monoxide alarms must be connected to an electrical circuit and they must be located near bedrooms and sleeping areas.
Depending on the size and design of your laneway house, installing a single combined smoke and carbon monoxide alarm may be sufficient to meet Building Code requirements, though you may want to consider going beyond the Code by adding additional alarms.
Relevant Building Code provisions: Division B, Articles 9.33.4.1., 9.33.4.2. and Table 11.5.1.1.C., Compliance Alternative 197.
Other considerations
Home Construction Regulatory Authority
In Ontario, all builders of new homes must be registered with the Home Construction Regulatory Authority (HCRA). HCRA maintains an Ontario Builder Directory of all new home builders. If you are considering building a new laneway house, we encourage you to check the Ontario Builder Directory to ensure your prospective builder is registered with HCRA.
Tarion
Tarion is responsible for all matters related to homeowner warranty protection. Tarion’s website outlines the types of homes covered by their warranties and protections. Tarion requirements do not apply when renovating an existing building to create a dwelling unit.
Building Code Commission
There is an appeals process through the Building Code Commission (BCC) that seeks to provide a fair and impartial way to handle disagreements that might arise on sufficiency of compliance with technical requirements of the Building Code, as well as issues related to the time frame for mandatory construction inspections and processing permit applications.
Tenancy
There are no provincial rules or requirements that would restrict who can live in your laneway house.
You should consider landlords’ obligations under the Residential Tenancies Act as they can sometimes affect choices about how to design a renovation, such as the requirement to maintain a minimum room temperature during certain parts of the year.
If you are planning on renting out your laneway house, learn what is required of you as a landlord from the Landlord Self Help Centre.
Case studies
New laneway house in Toronto
In 2019, the City of Toronto changed its zoning by-laws to allow the construction of laneway houses on residential properties that share a property line with a public lane.
The zoning by-law sets out requirements for laneway houses, such as landscaping, building height and number of storeys, floor area, lot coverage and setbacks.
These changes make it easier to build a laneway house, and since being passed, laneway houses have become increasingly popular across Toronto.
One of the new completed laneway houses livening up a Toronto laneway is the laneway house below, which was custom built with the owners’ daughter in mind. This is a great example of the economic and family benefits of adding a laneway house to your lot: it can increase your property value while providing a very familiar tenant with a reliable place to live.
Exterior of Toronto laneway house
Design
This laneway house is a new-build, two-storey, 1,050-square-foot building with a one-car garage. It includes a bedroom on the ground floor, a kitchen, three-piece bathroom and a principal bedroom on the second floor. The total construction time was less than a year.
Interior of Toronto laneway house
Construction process
The owners worked closely with an architect who managed many aspects of the project beyond the design and drawings of the laneway house, including:
- Initial property assessment
- Regular interactions and coordination with the municipality to:
- Ensure zoning compliance
- Get a building permit
- Organize necessary approvals
- Recommendations on general contractors
Because the laneway house was built for a family member, the design was personalized to meet the family’s needs. Hiring a professional that provided a suite of services allowed the homeowners to get everything they wanted for their laneway house within their budget and in compliance with municipal and Building Code requirements.
New laneway house in Hamilton
Over the last decade, there has been a growing demand for laneway houses in Hamilton as the city has undergone rapid transformation. There are hundreds of laneways in the city, and laneway housing is seen as one way to keep up with growing demand for additional supply of housing.
From conception to completion, building a laneway house is often considered a passion project. This passion is shared by many homeowners as well as those in the business of building laneway houses, such as developers and architects.
This new laneway house in the City of Hamilton is no different.
In fact, the owner envisioned adding a laneway house to his property when he first had his primary house designed and built. He began to bring his vision to life after the City of Hamilton passed their zoning pilot (PDF) in 2018 allowing the construction of laneway houses in certain areas of the city. Under this zoning pilot, laneway houses had to meet certain requirements, including:
- a maximum height of 6 m
- a maximum gross floor area of 50 m2
- a minimum distance of 7.5 m between the laneway and primary house
Design and permit process
Although the owner has experience as a general contractor, he understood the value of hiring professionals to help with this type of housing project, so he hired an architect to manage the design and permit process.
Following frequent interactions between the architect, the owner and the municipality, the drawings for the laneway house were revised as needed to ensure compliance with Building Code and municipal requirements. Once all details were in order, including meeting emergency access requirements, the building permit was issued quickly.
Exterior of Hamilton laneway house
Construction
Construction on the laneway house started in 2021 and the owner is taking his time to explore options for the right materials and the right contractors. This has helped keep costs low and for the homeowner to stay within his budget.
The design of the laneway house is open concept, including one-bedroom, a kitchen and laundry space. With construction well underway, the laneway house is expected to be completed in late 2021.
The plan is for the homeowner’s mother to move into this laneway house once she retires. That way she can be close enough to see her family regularly with the benefit of having her own space. Until then, it can be rented out to supplement the family’s income and help increase Hamilton’s housing supply.
Next steps
For best results with your project, we highly recommend you:
- contact your local municipality early in your planning and design process
- hire qualified professionals to help you
You can generally find a contact number for your local building and planning departments on your municipality’s website. You can also find information online or at your local municipal offices.
If you intend to hire a professional, you may want to consider your options and check references, reviews, insurance and accreditations. If applicable, you should check the qualifications of a provincially registered Building Code designer. In general, it can help to be familiar with the building process and to have a good understanding of all costs and terms associated with your project.
You can find Ontario’s Building Code online. You should also check out the following land use planning resources:
Acknowledgements
The ministry would like to thank the following groups and individuals for sharing their images and laneway housing project information.
- Cover photo, Images 1 and 2: Toms+McNally Design, Karin Dearness & Andy Stone
- Image 3: Shutterstock
- Images 5 and 6: Lanescape Architecture Inc., Jack Gelbloom & Jessica Goldstein
- Images 4, 7 and 8: David Dolezal
- New build in Toronto (case study): Lanescape Architecture Inc.
- New laneway house in Hamilton (case study): David Dolezal
Accessible image descriptions
Flow-chart: Flow-chart with four questions. If the answer is no to any of these questions, you will likely not be able to build a laneway house. If the answer is yes to all of these questions, keep reading and learn about key municipal and provincial requirements as you start to think about building a new or renovated laneway house!
Diagram 1: Aerial views of a neighbourhood demonstrate the difference between a property with a laneway house and properties with other types of additional residential units. The difference is that the property with a laneway house abuts a laneway. Property 1: a primary house and a laneway house.
Diagram 2: Aerial views of a neighbourhood demonstrate the difference between a property with a laneway house and properties with other types of additional residential units. The difference is that the property with a laneway house abuts a laneway. Property 2: a primary house and a coach house. Property 3: a primary house and a garden suite. Property 4: a primary house and a tiny home.
Diagram 3: A fire truck vehicle is parked on a main street in front of the primary house. A fire hydrant is within 45 metres of the fire truck, and the fire truck is within 45 metres of the laneway house. There is a path along the side of the primary house from the main street through to the laneway house in the backyard.
Diagram 4: Measurements of minimum floor area. Detailed description: Measurements taken between finished surfaces or separating wall (Division B, Subsection 9.5.1.2). Areas of closets or built-in bedroom cabinets are generally not included in minimum floor areas (Division B, Subsection 9.5.1.3).
Diagram 5: Diagram demonstrating how to calculate the size of a window in relation to the size of a room in a newly built laneway house. Example: if the living room floor area is at 15 m2 / 161.4 ft2, the minimum unobstructed glass area at 10% is 1.5 m2 / 16.1ft2.
Diagram 6: Diagram demonstrating how to calculate the size of a window in relation to the size of a room in an existing building. Example: if the living room floor area is at 15 m2 / 161.4 ft2, the minimum unobstructed glass area at 5% is 0.75 m2 / 8.1 ft2.
Diagram 7: A diagram of a 30-minute fire separation wall includes:
- 13 mm (1/2”) drywall
- entire stud cavity filled with fiber-type insulation
- 38 mm x 89 mm (2” x 4”) or 38 mm x 140 mm (2” x 6”) at 406 mm (16”) on-centre wood studs
- 13 mm (1/2”) drywall
Diagram 8: A diagram of a 30-minute fire separation floor/ceiling includes:
- one layer of 16 mm (5/8”) plywood subfloor on joists
- 38 x 241 mm (2” x 10”) joists spaced 406 mm (16”) on centre
- 89 mm (4”) thick fiber-type insulation between the joists
- one layer of 16 mm (5/8”) fire-rated drywall on ceiling
Diagram 9: A diagram showing that 33% of the exposing building face area of a laneway house is glazed. The laneway house has:
- an exposing building face with a maximum total area of 20 m2
- a limiting distance of 4 metres to the primary house
Diagram 10: Diagram demonstrating one way an upper floor window can be used as an emergency exit:
- minimum height of unobstructed opening not less than 1,060 mm (3’ 6”)
- minimum width of unobstructed opening not less than 560 mm (1’ 10”)
- 900 mm (2’ 11”) maximum above floor