Loading...
ADU Plans
ADU Plans designed, permitted and built across the 30 municipalities of the Greater Toronto Area - zoning review, permit drawings and construction handled by one team.
ADU Plans - Overview
Key Takeaways
- Key features: Permit-ready drawing set, Site plan with setbacks and coverage, Structural, HVAC and drainage details
Architectural drafting and permit-ready ADU plans - site plan, floor plans, elevations, sections and the structural details a municipality needs to issue a permit.
Features & Specifications
- Permit-ready drawing set
- Site plan with setbacks and coverage
- Structural, HVAC and drainage details
- Revisions until the permit is issued
- Plans usable with any builder
Key takeaways
- ADU plans are the drawing set a municipality will actually accept - floor plans, elevations, sections, site plan, structural details and the SB-10/SB-12 energy compliance sheet. Concept sketches are not plans.
- Every set starts from a site measurement and a municipality-specific by-law review, because setbacks, lot coverage, height and soft-landscaping ratios differ across the 30 GTA municipalities.
- On a 500-600 sq ft footprint, bathroom placement, the mechanical closet and the kitchen wall are decided by plumbing runs and clearances, not by preference.
- At $300-$600/sq ft, an extra 100 sq ft adds $30,000 to $60,000 of build cost - which is why cost consequences are attached at drawing stage, not after a tender comes back high.
ADU plans are the drawing set a municipality will actually accept: floor plans, elevations, sections, a site plan showing setbacks and lot coverage, structural details, and the energy compliance sheet filed under SB-10 or SB-12. They are not concept sketches. A plan set that cannot be submitted is a document that cost money and moved nothing.
We draw plans two ways. As the first stage of a design-build contract, where the same team that draws it builds it and prices are attached to decisions as they are made. Or as a standalone commission for owners who want permit-ready drawings to take to their own builder or to several builders for competitive quotes. Both start from the same place: a site measurement and a by-law review for the specific municipality, because setbacks, lot coverage, height limits and soft-landscaping ratios differ across the 30 GTA municipalities even under harmonised provincial criteria.
What this includes
- Permit-ready set: floor plans, elevations, sections, site plan, structural details and SB-10/SB-12 energy compliance sheet
- Site measurement and municipality-specific by-law review before the first line is drawn
- Standalone commission available - take the drawings to your own builder or tender them to several
- Small-footprint planning where plumbing runs and clearances drive the 500-600 sq ft layout, not preference
- Lane width and fire access route measured on lane lots; walkway, emergency route and services trench designed on lane-free lots
- Ceiling height, egress windows and fire separation resolved at drawing stage, not with an inspector on site
- Drawn against O. Reg. 299/19 (amended November 2024), O. Reg. 462/24 and Bill 23 as-of-right permission
- Cost consequence attached to each design choice at the $300-$600/sq ft GTA rate - 100 sq ft is $30K-$60K of build
The design work on a small unit is unusually tight. A 500 to 600 sq ft footprint has no wasted space in it, so bathroom placement, the mechanical closet and the kitchen wall are decided by plumbing runs and clearances, not by preference. Where a lot has a lane, we plan the unit around measured lane width and the fire access route. Where it has no lane, the walkway, emergency access route and services trench from the main house become the constraint. Ceiling height, egress windows and fire separation are set at drawing stage rather than negotiated with an inspector later.
The plan set is written against the Ontario Building Code, O. Reg. 299/19 on additional residential units as amended in November 2024, O. Reg. 462/24 harmonising garden-suite criteria, and Bill 23's as-of-right permission for up to three residential units on most serviced lots already holding a detached, semi-detached or townhouse dwelling. If the lot falls inside a TRCA or Credit Valley Conservation regulated area, the drawings are prepared to satisfy conservation authority review as well, mandatory since 1 April 2024.
Owners typically come to us with a rough footprint in mind and a budget target. Because construction runs $300 to $600 per square foot in the GTA depending on site access and finish, a plan set that adds 100 sq ft adds $30,000 to $60,000 in build cost - which is why we attach cost consequences to design choices at drawing stage rather than after a tender comes back high.
Once drawings are complete, the ADU building permit service takes the file through submission and plan-examiner comments to issuance.
ADU Plans - Permits and Approvals by Municipality
What approval typically costs, and what the lots look like, in the GTA municipalities we build in most.
| Municipality | Typical approval fees | Lot typology |
|---|---|---|
| Toronto | $8,000-$14,000 in permit, development and plan-review fees | Narrow downtown lots with rear public laneways - Toronto has over 300 km of them, more laneway frontage than any other Canadian city. |
| Brampton | $5,500-$10,000 including Brampton registration and Peel charges | Deep newer-subdivision lots, many with an existing unregistered basement apartment that must be brought to Ontario Building Code fire-separation standard. |
| Mississauga | $6,500-$11,000 in City of Mississauga and Region of Peel charges | Large 1970s-90s subdivision lots with attached garages; garage conversions and rear coach houses are both common outcomes. |
| York | $8,000-$14,000 under the City of Toronto fee schedule | Older narrow semi-detached lots on a laneway grid, with frequent shared-driveway conditions that must be resolved before permit. |
| Etobicoke | $8,000-$14,000 under the City of Toronto fee schedule | Split personality - laneway-served lakeshore grid in Mimico and New Toronto, versus large treed lots in The Kingsway where garden suites dominate. |
| Ajax | $7,000-$12,000 including Durham Region charges | Compact 1990s-2000s subdivision lots where the required 1.2 m side-yard construction access sets the maximum module width we can crane in. |
| King | $9,000-$16,500 including York Region and septic charges | Estate and agricultural parcels, many over an acre, on private well and septic with moraine core-area restrictions. |
| North York | $8,000-$14,000 under the City of Toronto fee schedule | Deep post-war bungalow lots, commonly 50 ft × 120 ft, with rear yards large enough for a detached garden suite plus the required 1.5 m separation. |
Fee bands are indicative, drawn from project experience - confirm current tariffs with the municipality before budgeting.
Related Unit Types
Frequently Asked Questions
Everything you need to know about our services.
Architectural drafting and permit-ready ADU plans - site plan, floor plans, elevations, sections and the structural details a municipality needs to issue a permit. Concretely that means: permit-ready drawing set; site plan with setbacks and coverage; structural, hvac and drainage details; revisions until the permit is issued. One contract covers design, permit and construction, so there is no handoff between a designer and a builder halfway through.
Related service: Accessory Dwelling Units
On a 700 sq ft reference unit our estimate band runs $16,000-$32,500 in King up to $17,000-$34,000 in East York - roughly $385 to $402 per square foot. The spread is not a markup: this work involves drawings, calculations and the permit submission rather than construction, and the per-municipality difference comes from approval fees, frost depth and snow load. Final pricing follows a site visit.
Related service: Accessory Dwelling Units
Yes - a building permit is required in every GTA municipality. Bill 23 (More Homes Built Faster Act, 2022) and O. Reg. 299/19 permit up to three residential units as-of-right on most serviced lots, so a rezoning application is usually not needed.
Municipal approval costs range from $5,500-$10,000 including Brampton registration and Peel charges in Brampton to $9,000-$16,000 including Peel Region and septic permit charges in Caledon, quoted separately from construction. Plan review typically takes four to eight weeks.
Related service: ADU Building Permit
All 30 municipalities of the Greater Toronto Area, from Toronto out to Clarington. Each one has its own by-law, fee schedule and review stream, and we file into the local one - the municipal page for your address carries that city's approval band, frost depth and building season.
Related service: Accessory Dwelling Units
Eight to fourteen months is the honest end-to-end range: design and drawings, four to eight weeks of plan review, then construction. Because this work is drawings, calculations and the permit submission rather than construction, the build phase is the part that moves most between projects. Excavation is scheduled inside the local building season, and interior work carries on through winter.
Related service: Accessory Dwelling Units
Ready to Get Started?
Ready to start your adu plans project? Send us your address and we will tell you what your lot allows, what it costs and how long the permits take.