WE ARE THE ACCESSORY DWELLING UNIT EXPERTS
ADU Permit Drawings in Ontario
Planning a backyard garden suite, laneway home, or detached rental unit? Additional Dwelling Units (ADUs) are one of the fastest-growing housing solutions in Ontario — but they must meet strict requirements under the Ontario Building Code. We prepare BCIN-certified ADU drawings with all the structural, fire safety, and egress details municipalities expect, so your project can move forward without costly delays.
We are Ontario's ADU Experts
What We Include
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Existing & proposed floor plans with full dimensions
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Egress window and door details for bedrooms and exits
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Fire separation details for walls, ceilings, and service rooms
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Smoke & carbon monoxide alarm locations
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HVAC notes for heating/ventilation compliance
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Elevations and building sections as required
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Permit-ready drawing package to Ontario Building Code
The Process
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Free consult – Tell us about your ADU project.
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Measure & verify – Provide lot dimensions/photos, or we can arrange a site measure.
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Design & drawings – Code-compliant plans prepared to OBC.
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Review & revisions – Adjustments until drawings are permit-ready.
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Permit support – Guidance through municipal submission.
Turnaround & Pricing
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First draft typically in 5 business days from site measure
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Pricing depends on ADU size, complexity, structural elements and municipality requirements
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Transparent, upfront quotes with add-ons priced separately
FAQs
Do I need a permit for an ADU?
Yes. Every Additional Dwelling Unit in Ontario requires a building permit.
Can every property have an ADU?
Not always. Municipal zoning rules apply, and some lots may need planning approval. We design to Ontario Building Code but zoning permissions must be confirmed with your city.
Do ADUs need fire separations?
Yes. Fire-rated walls/ceilings and interconnected smoke/CO alarms are required. We document these details in your plans.
What about HVAC and plumbing?
Municipalities expect heating/ventilation notes and plumbing details if applicable. We include them in your drawings.
What is the minimum ceiling height for a basement ADU?
In Ontario, the minimum finished ceiling height for most living spaces in a basement ADU is 1.95 m (6’5”). Some areas under beams, ducts, or bulkheads may be allowed as low as 1.85 m (6’1”), provided they don’t extend too far. We design with these clearances in mind to keep your ADU code-compliant.
What if I have an existing illegal basement ADU — can you help legalize it?
Yes. We can prepare as-built drawings and help you through the retroactive permit process. This often includes documenting existing conditions, identifying code deficiencies, and designing corrective solutions so your ADU can be approved legally.
Do I need parking for an ADU?
Parking requirements vary by municipality. Many cities have eased parking rules for ADUs, but some still require at least one space. You’ll need to confirm with your local planning department.
Start your ADU design now
Want to learn more?
Check out our other residential design project types here