Use the winter to get a garden suite ready for spring

A garden suite feels like a summer project. But the questions that decide whether a suite can be built at all have nothing to do with the weather: where the property lines are, how a firefighter would get from the street to the front door, which trees are protected, how deep the sewer is and what the zoning allows. Every one of those can be answered between November and March.

Start in the fall and you can reach spring with a design, a zoning answer and possibly a permit. Start in May and the best building months go to paperwork. If you haven’t yet decided between a suite and an addition, our guide to choosing between a garden suite and a home addition is the place to begin.

The steps below follow Toronto’s process, because it’s the most detailed in the GTA. Other cities have their own rules for backyard homes, and our garden suites page compares them.

This is the order we work through with homeowners over the winter. Each step feeds the next, so it pays to keep them in sequence.

1. Pull together what’s on file

   Find your survey, any old permit drawings and the drain plan for the house. Toronto Building can provide site plans, surveys and drain plans it holds for a property.

2. Measure the route from the street

   Walk and measure the path a firefighter would take to the suite’s door, including its width and headroom, before anyone draws a floor plan.

3. Map the trees, yours and your neighbours’

   Measure trunk sizes and mark every tree that could be affected by the suite, the trench or the access route, including those over the fence.

4. Find out where the services will come from

   Check the depth and route of the sewer, the capacity of the electrical panel and how the suite will be heated.

5. Choose a design route

   Decide between a custom design and one of the City’s pre-approved plans, placed on your actual site plan.

6. Get the zoning confirmed

   Apply for the City’s zoning certificate, and file a minor variance if the design needs one.

7. Apply for the permit and any fee deferral

   Submit the complete permit application, and apply for any development-charge deferral at the same time.

Nearly every later step relies on knowing exactly where your property lines are and what’s already built on the lot. If you have a recent survey from when you bought the house, dig it out; it’s the first thing we ask for. If the house has changed since, or there’s no survey at all, ordering one from an Ontario Land Surveyor is the first winter task, because the designer, the zoning examiner and the tree plan all start from it.

Old records help too. Toronto Building keeps the site plans, surveys and drain plans from past permits, and its records policy allows those to be released for a property. A drain plan can show where the sanitary line leaves the house, which is exactly what a garden suite needs to connect to.

While you’re gathering, photograph the side yards, the back of the house, any shed or garage and the rear fence line. Winter photos are useful, not a drawback: with the leaves down, trees, overhead wires and the neighbours’ windows are all easier to see.

This measurement rules more Toronto lots in or out than any other, so we do it before design. The path runs from the public street to the suite’s entrance. Without extra fire-safety measures it can be up to 45 metres long. With one of the City’s two options, a sprinkler system or upgraded fire-resistant construction, each combined with an exterior strobe light and alarms, it can stretch to 90 metres.

The width depends on the building. For a suite without sprinklers, the path needs to be at least 1.0 metre wide and 2.1 metres high; for a sprinklered suite, 0.9 metres wide and 2.1 metres high. Hydro and gas meters are allowed to stick out into that width, but sheds, air conditioners, steps and gates need a closer look. The path can run over your own land or, where yours is too narrow, through an agreement with your neighbour.

We walk it with a long tape: from the sidewalk, down the side of the house, through the gate and across the yard to where the suite’s door would be. We note every pinch point and change in level. Because these requirements come from the Building Code, a minor variance can’t relax them, so it’s far better to know your numbers now than after the drawings are paid for.

In Toronto, any tree on private property that’s 30 centimetres or more in diameter is protected, and injuring or removing one needs a permit. The City measures at 1.4 metres above the ground, and if a tree has several stems, the largest one decides. Injury includes more than cutting: digging in the root zone, changing the grade and even storing materials or equipment there all count.

If the suite, its foundation, the service trench or the access route could affect a protected tree, the permit application needs an arborist report and a tree protection plan. That plan shows trees on your lot and on neighbouring properties within six metres, each numbered, with protection zones and hoarding drawn to scale. An arborist can do that assessment in winter, and it often changes where the suite can go, so we like to have it before design starts.

The rules are also moving. Since September 1, 2026, large healthy trees over 61 centimetres in diameter can be identified as Distinctive Trees, and their status is weighed in any permit to injure or remove them. City Council has also endorsed lowering the private-tree threshold from 30 to 20 centimetres, pending a report in 2027. If your yard has trees in that 20 to 30 centimetre range, plan as if they might be protected by the time you build.

A garden suite is a small house, and it needs a sanitary drain, water, electricity and heat, usually drawn from the main house. Winter is a good time for us to find out what we’re working with, because the investigation happens in the basement and the electrical room.

Start with the drain. A plumber can run a camera through the main sewer line to see its route, its condition and roughly how deep it sits where it leaves the house. That depth matters: if the suite’s bathroom sits lower than the point where it connects, gravity won’t do the job and a pump comes into the plan. Knowing this early lets the designer place the bathroom and kitchen where the plumbing works.

Then the power. Ask a licensed electrician to look at the main panel and the service coming into the house, and to estimate the load a second home would add. A suite with electric heat, a heat pump, an oven and a dryer adds a lot to a panel that may already be busy. If the service needs upgrading, that involves the utility and an ESA inspection, and it’s much easier to plan in February than to discover in June.

Toronto offers four pre-approved Made in Toronto designs for garden and laneway suites. Toronto Building has already reviewed the buildings themselves against the Ontario Building Code and the zoning by-law, so that part of the design won’t be reviewed again. When you apply, you reference the plan number rather than submitting the drawings.

The review that remains is about your lot: where the suite sits, the setbacks around it, the access path, the trees, the grading and the service connections. And the City is clear that whoever uses a pre-approved plan, you or your designer, takes responsibility for the design and for confirming it suits the property.

Winter is the right time to make this choice. We lay each design over your survey to see how it sits against the access path and the tree protection zones. If one fits as drawn, it can save real time and cost. If it needs changes to work on your lot, a custom design may be simpler than adapting a standard one. We’re happy to look at both with you on paper before you commit.

Toronto recommends getting a zoning certificate, known as a ZAP, before the building permit. It’s a detailed review of your drawings against the zoning by-law and other laws that apply, and once it’s issued, your permit application counts as complete. The fee you pay for it is credited against the permit fees. Garden suites are reviewed in the City’s House Stream, where complete applications are reviewed within 10 business days; an application without the certificate has no review timeframe at all.

Two zoning details catch people out. First, the 2022 by-law that allowed garden suites applies under the current city-wide zoning by-law, not to properties still zoned under a former municipal by-law, such as the old Etobicoke code or the former City of North York’s. If your lot is one of those, the route is different. Second, the provincial regulation O. Reg. 462/24, in force since November 20, 2024, changed several zoning rules for garden suites, so we check the current rules rather than an older summary.

If the design needs relief from a rule, a minor variance from the Committee of Adjustment comes before the permit, and we like to see it filed over the winter so it stays off the spring schedule.

Development charges can make a big difference to a suite’s budget, so look at them before you set one. In many cases a garden suite as an additional unit on a residential lot is exempt, and the City confirms the position for your proposal. Where a charge does apply, Toronto’s Laneway and Garden Suite Development Charges Deferral Program can defer it for 20 years from the date the building permit is issued. It becomes payable within that period only if a new lot is created, for example through a severance or a condominium.

The City says the deferral review takes 15 to 20 business days and recommends applying as soon as you apply for the building permit. That makes it a natural part of the winter paperwork. We keep fees, exemptions and deferrals out of our construction estimate, so you can see the cost of the building on its own.

If the winter goes to plan, this is the folder you’ll have by spring.

• A current survey and a site plan showing the suite, the access path and every nearby tree
• An arborist report and tree protection plan, and a tree permit if one is needed
• Drawings, custom or based on a pre-approved plan, with the services routed
• An issued zoning certificate, and any minor variance decided
• A complete permit application, plus any development-charge deferral application
• A written construction estimate that separates the building, the site work, the services and exclusions
• A plan for getting materials and equipment into the backyard, and for keeping your family’s route to the house clear

These pages cover the rest of the picture.