Pre-Approved Garden Suite Plans in Ontario every program we could find, and what they leave out
Toronto, Mississauga and the federal CMHC catalogue give plans away free. St. Catharines, Whitby, Pickering, Peterborough and Barrie point you to designers you pay. Every one of them pre-approves the building, not your lot. You still owe the city a site plan, a grading plan and proof the suite fits your yard.
At a glance
The $129,999 + HST figure is the St. Catharines-listed Backyard Homes Beech model, priced for construction of the unit. Site work, servicing and permits are not described as included.
Yes, Ontario has pre-approved garden suite plans. Toronto offers 24 free plan numbers, Mississauga has a free 40 m² studio and 55 m² one-bedroom, and CMHC’s catalogue has two free ADU designs. Whitby, Pickering, Peterborough, Barrie and St. Catharines list designs you buy from the designer. None of them covers your site plan, grading, servicing or zoning fit.
The Building Is Approved. Your Backyard Isn’t.
Here is the honest version first. A pre-approved plan means somebody at the city already checked the drawings of the building itself against the Ontario Building Code. That saves the plans examiner a few weeks of looking at the same stud walls over and over. It does not mean your suite is approved.
Every program we checked says the same thing in different words. Toronto says pre-approval “doesn’t guarantee zoning compliance” and the placement still gets a full review. Pickering says permits are still reviewed against site-specific conditions. Barrie goes further and says the City doesn’t guarantee its listed designs meet the Building Code or zoning at all.
So think of a pre-approved plan like a pre-cut set of stairs. Very handy. It still has to land on a floor that’s the right height, and that part is your problem.
Three kinds of “pre-approved” in Ontario
- Free city plan sets. Toronto and Mississauga publish the drawings. You cite the plan number on your permit application instead of uploading the plans.
- City-listed designs you buy. Whitby and Pickering share a regional catalogue. Peterborough, Barrie and St. Catharines list designs too. You contract with the designer or supplier and pay their fee.
- The federal CMHC Housing Design Catalogue. Free designs, including two accessory dwelling units for Ontario. Mississauga and Greater Sudbury say their staff “pre-reviewed” them, which is not the same as pre-approved.
Pre-Approved Garden Suite Plans: every program, side by side
We read each city’s own page in October 2026. Where a city does not publish a number, we say so instead of guessing. Click through before you rely on anything here, because these pages change.
| Program | What you get | Sizes | Cost to use | What it leaves out |
|---|---|---|---|---|
| Toronto | 4 designs (studio and two-bedroom, garden and laneway) in heat pump or forced air versions, each with 3 fire access versions = 24 plan numbers. Plans updated August 17, 2026. | Not stated on the city page; check the plan PDFs | Free. Normal permit fees apply ($18.56 per m² for Group C dwellings, 2026) | Site plan from a current survey, lot grading plan to the infill criteria, Schedule 1 designer info, road damage deposit, infill notice, tree declaration, overhead conductors declaration, plumbing details if you tie into the house |
| Mississauga | Studio and one-bedroom garden suite plans plus a materials list (no pricing, servicing or labour) | 40 m² (430 sq ft) and 55 m² (600 sq ft) | Free. Permit fees per fee schedule, $77.20 + HST address fee, some DCs may apply | Site plan, grading and drainage plan, Applicable Law form, second unit registration if applicable, water service sizing form or Region of Peel connection approval |
| St. Catharines | 4 detached ADU designs from 2 suppliers (OCI Group, Backyard Homes Canada) | 37 m² to 80 m² | Published prices $129,999 + HST to $225,000 (see table below) | Detailed construction drawings and a site plan are still required with the permit. Setbacks and parking checked at permit stage |
| Whitby and Pickering (shared catalogue) | 5 detached ADU designs from local architects and designers, plus CMHC ADU 01. Purchase includes foundation and HVAC plans | 264 to 634 sq ft, studio and one-bedroom | Not published; you buy from the designer | Site plan of your property (buy it from the designer), zoning check against your lot. Design “should not be altered” |
| Peterborough | Pre-Approved Plans Program for detached ARUs by local BCIN or P.Eng. designers. Catalogue lists one design so far (“Dalton 1”), more promised | Not stated on the city page | Not published; you contact the designer | Construction drawings, site servicing report, site plan, heritage or conservation authority approval if needed. Modified plans lose priority review |
| Barrie | 4 standardized coach house designs from a local architect (studio and one-bedroom, gable or shed roof), plus links to CMHC designs | Not stated | Set by the designer; the City takes no payment | Zoning compliance, site and grading plans, permit fees, inspections. City does not guarantee Code or zoning compliance |
| CMHC catalogue (Ontario versions) | ADU 01: single storey, one bedroom, accessible-ready. ADU 02: two storeys, three bedrooms, carport | ADU 01: 59 m² (634 sq ft). ADU 02: 95 m² (1,017 sq ft) gross | Free download | Not a city approval. Mississauga says you need a qualified professional to amend them; site plan, forms and zoning fit are on you |
| Ottawa | No pre-approved coach house plan program found on the city’s coach house page | – | – | Ottawa sends you to a pre-application consultation with planning staff (call 3-1-1) and, if needed, the Committee of Adjustment |
Last checked October 2026 · Sources: Toronto, Mississauga, Pickering, Peterborough catalogue, city pages linked in the table
Two more worth knowing. Mississauga’s own CMHC catalogue page says staff pre-reviewed ADU 1 and ADU 2 to “help streamline” approvals, and that the plans are free but must be amended by a qualified professional. Greater Sudbury pre-reviewed the same two ADU designs and calls them “near permit-ready.” Note that CMHC’s ADU 02 page lists 95 m² gross but an image caption on the same page says about 700 sq ft, so measure from the drawings, not the caption.
St. Catharines Publishes Prices. Read the fine print anyway.
St. Catharines is the only Ontario program we found that lists dollar figures next to its pre-approved designs. That’s useful. It’s also easy to misread.
| Model | Supplier | Size | Bedrooms | Published price |
|---|---|---|---|---|
| Beech | Backyard Homes Canada | 37 m² (about 398 sq ft) | 1 | $129,999 + HST |
| OCI Small | OCI Group Canada | 50 m² (about 538 sq ft) | 1 | $160,000 (estimated construction cost) |
| Maple | Backyard Homes Canada | 54 m² (about 581 sq ft) | 2 | $189,999 + HST |
| OCI Large | OCI Group Canada | 80 m² (about 861 sq ft) | second bedroom option | $225,000 (estimated construction cost) |
Last checked October 2026 · Source: City of St. Catharines, pre-approved detached ADU designs (square feet converted by us)
The city page calls the OCI numbers an estimated construction cost that varies with fixtures, finishes and trades. The Backyard Homes numbers are for “the construction of the unit.” The page does not say the prices include design fees, site work, servicing or permits, so assume they don’t until the supplier puts it in writing.
The city also lists a Community Improvement Plan ADU grant of up to 70 per cent of eligible costs, to a maximum of $80,000 for an exterior unit. The city’s Community Improvement Plan page now says (update of April 16, 2026) that funding has been depleted and the ADU Program is closed. Do not count on it unless the city reopens it.
Parking is spelled out too: 0.5 spaces per ADU, and 1 for the main house. That’s the kind of small number that kills a plan on a narrow lot, so check it early.
What Free Plans Never Cover and why it’s the expensive half
The drawings of the box are maybe a quarter of the paperwork. The rest is about your lot, and nobody can pre-approve that for you.
Site plan
Property lines, setbacks, lot coverage, the house, the suite, the driveway. Toronto wants it referenced to a current survey. If you don’t have a survey, budget for one.
Grading and drainage
Toronto requires a lot grading plan to its infill criteria; Mississauga a grading and drainage plan. Water has to leave your lot without landing on the neighbour. Inspectors check this at final.
Servicing
Water, sewer and hydro to the suite. Mississauga wants a water pipe sizing form if you share the house connection, or Region of Peel approval for a new one. This is where yards get dug up and budgets get eaten. See servicing costs.
Fire access
A clear path from the street to the suite door. Mississauga’s version is 1.2 m wide, 2.1 m high, no more than 45 m. Toronto’s plans come in three fire access versions because this one decides so many lots.
Foundation for your soil
Whitby’s catalogue includes foundation plans. Others don’t say. Either way the plan assumes average conditions; clay, fill, a high water table or a slope can change the footing. See foundation options.
Heat loss and HVAC
Toronto’s plans come in heat pump and forced air versions, and Whitby’s purchase includes HVAC plans. Elsewhere you may need a room-by-room heat loss and duct design. We use OntarioHeatLoss.ca for BCIN-stamped designs.
Trees
Toronto wants a tree declaration form if a by-law protected tree could be affected. A big maple at the back fence can move your suite more than any setback.
Zoning fit
Height, size, separation from the house, coverage, parking. The plan is fixed, your lot is not. If the fixed box doesn’t fit, you’re looking at a minor variance or a different plan.
Rural lots
None of these programs is aimed at lots on a well and septic. If that’s you, septic capacity is usually the first question. Septic design goes through SepticReplacement.ca.
Got a pre-approved plan number? We’ll do the rest of the pile.
Our Urban Pre-Approved Wrapper covers the site plan, grading coordination, forms and heat loss where needed, from $1,499.99 + HST. Send the plan number and your survey and we reply with a fixed quote.
Move One Window and it’s not pre-approved anymore
This catches more people than anything else on this page. Pre-approved means approved exactly as drawn. Change it and you are back in the regular review line with a design nobody has checked.
- Toronto: any modification, including HVAC or plumbing changes, removes the pre-approved status.
- Mississauga: you can change siding, windows, doors and flooring. You can’t change the size or layout, including where walls, doors, windows and rooms sit.
- Whitby and Pickering: the design “should not be altered.”
- Peterborough: unmodified plans get priority; modified plans go through the usual review and may take longer.
Our advice is simple. If you already know you want a bigger bathroom, a second door or a different roof, don’t fight the pre-approved plan. Get a design that suits you and the lot from the start. You’ll spend less time arguing with a drawing that was never meant for you.
Using a Pre-Approved Plan in the right order
Most people pick the pretty plan first and check the lot second. Do it the other way around and you skip a lot of grief.
Check your lot before you fall for a plan
Confirm your zone allows a detached unit, then check setbacks, height, separation from the house and fire access. Our free Rules Checker is the fast way to start.
Get a current survey
Toronto’s site plan has to be referenced to one. An old survey that doesn’t show the deck, the shed and the new fence is a recipe for a 30 cm surprise.
Pick the plan that fits without changes
Lay the footprint on the survey with the required setbacks drawn in. If it only fits with changes, it isn’t the right plan. In Toronto, pick the fire access version that matches your actual path.
Sort out servicing
Decide whether water and sewer tie into the house or run separately, and where hydro comes from. Your town’s forms differ; Mississauga’s are listed above.
Prepare the site plan, grading plan and forms
This is the work the free plan doesn’t do. A designer with a BCIN signs Schedule 1 in most cases.
Apply and quote the plan number
Toronto wants the plan number in section B(ii) of the permit application. Mississauga wants the model type in the description of work. Peterborough wants the catalogue number in the permit description.
Build and pass inspections
Pre-approved drawings don’t skip a single inspection. Footings, framing, plumbing, insulation and final still get looked at on site.
Free Plans, Not a Free Suite
A free plan set saves design fees. It doesn’t change what lumber, concrete, trenching and trades cost. When Toronto released its plans in July 2025, CBC reported typical garden and laneway suite projects of $200,000 to $350,000, and pointed out the designs were not field-tested, so you can’t walk through one before you commit.
That’s fair. A drawing that’s never been built hasn’t had its first winter. We’d want to see how the details handle snow load at the eaves and water at the door before we built ten of them.
Where homeowners go wrong
- Assuming “pre-approved” means approved. It means the drawings of the building were reviewed.
- Reading a supplier’s price as the total. The St. Catharines prices are for the unit; your yard is extra.
- Changing the plan after they apply. That resets the review.
- Forgetting fire access. A 45 m path with a hydro meter in the way is a path that doesn’t count.
- Skipping the survey. Setbacks are measured from property lines, not from the fence your neighbour built in 1987.
Barrie owners should also read our Simcoe County secondary suite grant page. Barrie lists a 50 per cent ARU permit fee reduction in 2026, the County’s program of up to $50,000 per unit in exchange for affordable rent, and up to $15,000 more through the Barrie Bonus. If you’re in Simcoe County or around Georgian Bay, ICFhome.ca builds garden suites there.
Not sure a pre-approved plan fits your lot?
Our $399 + HST Garden Suite Feasibility Report checks your zoning, setbacks, fire access and servicing in 48 hours, and tells you which plan, if any, drops in without changes. The fee is credited toward permit plans or a build.
Pre-Approved Plans: straight answers
Are pre-approved garden suite plans free in Ontario?
Some are. Toronto’s 24 plan numbers, Mississauga’s two plans and CMHC’s catalogue designs are free to use. Whitby, Pickering, Peterborough and Barrie list designs you buy from the designer, and the price isn’t published on the city pages. You still pay normal building permit fees everywhere, plus whatever it costs to prepare the site plan, grading plan and forms.
Does a pre-approved plan mean I don’t need a building permit?
No. Every program we checked still requires a full building permit application. The pre-approval only covers the drawings of the building. The city still reviews where it sits on your lot, the zoning, servicing, grading and fire access, and inspectors still visit during construction.
Can I change a pre-approved plan?
Barely. In Toronto any change, even to the HVAC or plumbing, removes pre-approved status. Mississauga lets you change siding, windows, doors and flooring but not size or layout. Whitby and Pickering say designs should not be altered. Peterborough reviews modified plans the normal way, which takes longer. If you need changes, a custom design is usually the cleaner route.
How big are Mississauga’s pre-approved garden suites?
The studio is 40 square metres (430 square feet) and the one-bedroom is 55 square metres (600 square feet). Both have a three-piece bathroom. The city requires at least 1.8 m to the rear lot line, 0.6 m to an interior side lot line and 2.5 m to a street-side lot line, plus a fire access path at least 1.2 m wide, 2.1 m high and no more than 45 m long.
What are the St. Catharines pre-approved ADU prices?
The city lists the Backyard Homes Beech (37 m2, one bedroom) at $129,999 plus HST, the Maple (54 m2, two bedrooms) at $189,999 plus HST, the OCI Small (50 m2) at an estimated $160,000 and the OCI Large (80 m2) at an estimated $225,000. The page does not say these include site work, servicing, design or permits.
Does Ottawa have pre-approved coach house plans?
We did not find a pre-approved coach house plan program on the City of Ottawa’s coach house page as of October 2026. The city recommends a pre-application consultation with planning staff, booked through 3-1-1, and says a minor variance through the Committee of Adjustment is the route if your property can’t meet the rules. The CMHC catalogue designs can still be used anywhere as a starting point.
Can I use the CMHC Housing Design Catalogue ADU designs in my town?
You can download them free and use them as a base, but they are not a municipal approval. The Ontario ADU 01 is a single-storey, accessible-ready one-bedroom of 59 m2 (634 sq ft). ADU 02 is a two-storey, three-bedroom with a carport. Mississauga says a qualified professional must amend them, and you still need a site plan, forms and zoning fit for your lot.
What does a pre-approved plan leave out?
Everything specific to your lot: the site plan from a current survey, the grading and drainage plan, water, sewer and hydro servicing, fire access, tree forms, zoning checks for setbacks, height and coverage, and often the heat loss and HVAC design. On rural lots, septic capacity. That paperwork is what our permit packages cover.