“Pre-Approved” Does Not Always Mean Approved For Your Lot
Homeowners often search for pre-approved garden suite plans because they want to save time and avoid starting from a blank page. That makes sense. A catalogue plan can help with layout, design direction, and technical documentation, but it still needs to work on your property. The City will still care about zoning, lot coverage, setbacks, yard location, servicing, grading, building code, rental licensing, and the ARU rules in effect when you apply.
The catalogue is a strong starting point, not a permit decision.
Compare CMHC ARU PlansWhat The CMHC Housing Design Catalogue Can Help With
The CMHC Housing Design Catalogue includes standardized housing designs, including accessory dwelling unit options. These designs can give homeowners and designers a faster starting point than a custom plan from scratch, but they still need to be checked against the property through the zoning guide and setbacks guide.
- Helps compare unit sizes and layouts
- Gives designers a more developed starting point
- May reduce early design friction
- Can support a more informed builder conversation
- Still needs local adaptation and review
Near Permit-Ready Does Not Mean Permit-Approved
A plan can be technically advanced and still fail on a specific lot. London homeowners should treat catalogue plans as a head start, not a shortcut around zoning, permits, servicing, or professional review. The right question is not “Do I like this floor plan?” It is “Can this plan legally and practically fit my property?”
The right question is not “Do I like this floor plan?” It is “Can this plan legally and practically fit my property?”
Check The Property Before You Fall In Love With A Plan
Before choosing a garden suite or backyard home plan, screen the property for the major feasibility checks. The plan should come after the lot, not before it.
- Schedule A zoning code
- Eligible ARU location
- Rear and side yard setbacks
- Lot coverage remaining
- Maximum bedroom count
- Main dwelling size relationship
- Servicing route
- Access for construction
- Rental licence requirements
- CMHC rent-cap assumptions if using the $45,000 loan
CMHC ADU 01: A Strong Starting Point For A 1-Bedroom ARU
The research file identifies CMHC Ontario Accessory Dwelling Unit 01 as a 59 sq. m. / 634 sq. ft. design with 1 bedroom and 1 bathroom. For London homeowners looking at the affordable detached ARU stream, this type of compact 1-bedroom layout may align more naturally with the 1-bedroom CMHC rent-cap planning value.
Even with a compact plan, the property still needs to satisfy London zoning, setbacks, lot coverage, servicing, Ontario Building Code, and permit requirements.
Check The 1-Bedroom Rent CapCMHC ADU 02: Useful Inspiration, But Needs London Review
The research file identifies CMHC Ontario Accessory Dwelling Unit 02 as a larger 95 sq. m. / 1,017 sq. ft. design with 3 bedrooms and 1 bathroom. That may be useful as design inspiration, but London’s interim ARU rules currently limit each ARU to a maximum of 2 bedrooms.
Do not promote or rely on a 3-bedroom ARU plan unchanged for London without confirming current City rules and adapting the design.
Review London ARU RequirementsBigger Plans Are Not Always Better
A larger garden suite may look more valuable because it can house more people or command more rent, but the affordable detached ARU stream uses CMHC rent caps and London’s ARU rules limit bedroom count. Larger plans can also create more challenges with lot coverage, setbacks, servicing, construction cost, and financing. The best plan is not the biggest plan. It is the plan that fits the lot, the rules, the budget, and the capped rental income.
How Plans Connect To The $45,000 London ARU Loan
The $45,000 affordable detached ARU forgivable loan can help eligible homeowners, but it does not make a plan approvable. The project still needs to meet City program rules, zoning, rental licensing, affordability requirements, CMHC rent caps, and timing requirements. If the homeowner wants to use the loan, the application should be reviewed before work begins or construction commitments are made.
Read The London ARU Grant GuideUse Plans To Have Better Builder Conversations
A catalogue plan can make the first conversation with a designer or builder more productive. Instead of asking, “What can I build?” the homeowner can ask, “Can this type of layout fit my lot, services, budget, and City requirements?” If the next step is choosing professionals, use the garden suite builder checklist first.
- Can this plan fit my zoning and setbacks?
- Does it stay within lot coverage?
- Does it need bedroom-count changes?
- Where would services run?
- What site conditions could increase cost?
- What drawings or engineering would still be required?
- Would this work with the City loan timing?
Common Mistakes With Garden Suite Plans
Choosing the plan before checking the lot is one of the most common mistakes. A floor plan may look perfect but fail setbacks, lot coverage, servicing, or bedroom-count requirements. CMHC does not mean City-approved, the rent cap should be modelled if the loan matters, and hidden site costs can still change the decision.
- Choosing the plan before checking the lot
- Assuming CMHC means City-approved
- Ignoring the rent cap
- Forgetting hidden site costs
Interactive evaluator
Compare the two CMHC plans by the goal that matters most
Choose the priority first. The evaluator will highlight the better fit and surface the warning signs that matter for London's grant rules and interim bedroom limit.
CMHC Ontario ADU 01
ADU 01
634 sq. ft., 1 bedroom, 1 bathroom, and the cleanest first conversation for the grant path.
- Floor area
- 634 sq. ft.
- Bedrooms
- 1 bedroom
- Bathrooms
- 1 bathroom
- Redesign effort
- Light
- Local review
- Required
CMHC Ontario ADU 02
ADU 02
1,017 sq. ft., 3 bedrooms, and best used as a redesign reference rather than a direct fit.
- Floor area
- 1,017 sq. ft.
- Bedrooms
- 3 bedrooms
- Bathrooms
- 1 bathroom
- Redesign effort
- Heavy (Mandatory)
- Local review
- Absolutely Required
Evaluator result
Recommended for London
ADU 01 is the cleanest first conversation. Its smaller footprint fits tighter backyards, and it perfectly aligns with the $1,371/month 1-bedroom rent cap required for the $45,000 forgivable loan.
Warnings
- Even though it is near permit-ready, local review is still required.
FAQ
Pre-Approved Garden Suite Plan FAQs
Are there pre-approved garden suite plans in London, Ontario?
Homeowners may find catalogue or near-permit-ready plans, including CMHC ADU designs, but these should not be treated as automatic City of London approvals. Each property still needs zoning, permit, servicing, and building code review.
Are CMHC ADU plans approved by the City of London?
No. CMHC catalogue plans can be useful starting points, but they still need to be adapted to the specific property and reviewed against London zoning, Ontario Building Code, servicing, and permit requirements.
Can I use CMHC ADU 01 in London?
CMHC ADU 01 may be a useful 1-bedroom starting point, but it still needs review for the lot, zoning, setbacks, lot coverage, servicing, and permit requirements.
Can I use CMHC ADU 02 in London?
CMHC ADU 02 may be useful inspiration, but the research file identifies it as a 3-bedroom design. London’s interim ARU rules currently limit each ARU to a maximum of 2 bedrooms, so the design would need review and likely adaptation before being promoted for a London detached ARU.
Should I pick a plan before checking zoning?
No. Check zoning, lot coverage, setbacks, servicing, and bedroom limits before committing to a plan. A design that looks good online may not fit the property.
Do pre-approved plans make the permit process faster?
They may help reduce design time or make conversations more efficient, but they do not remove the need for local review, complete drawings, permit submission, inspections, and City approval.
How does the $45,000 ARU loan affect plan choice?
If the homeowner wants to use the affordable detached ARU forgivable loan, the plan should be reviewed against the program rules, affordability period, CMHC rent cap, owner-occupancy, rental licensing, and application timing requirements.
What should I ask a builder before paying a deposit?
Ask whether the plan fits zoning, setbacks, lot coverage, bedroom limits, servicing route, access, grading, permit requirements, and the City loan timing. Do this before committing to a paid deposit if possible.
Choose The Plan After You Check The Lot
Use the CMHC plan evaluator to compare the two options before you spend money adapting a plan, hiring a designer, or paying a builder deposit.
Compare CMHC Plans Read The ARU Zoning Guide