Kuzyn Builds offers three pre-designed detached ADU models in London, Ontario: The Paul (321 sq ft studio, 1 bathroom, from $148,000), The Maria (409 sq ft, 1 bedroom, 1 bathroom, from $168,000) and The Henry (549 sq ft, 2 bedroom, 1 bathroom, from $218,000). All three are standalone garden suites, all include a Tarion warranty, and all take roughly 4 to 8 months to build.
Those are the headline numbers. Below is how the three models actually differ in layout, use case and total cost once site work is added — so you can decide which one fits your lot and your budget before you call anyone.
Which ADU model is right for your London property?
The right model depends on who will live in it and how much backyard you are willing to give up. The Paul suits a single occupant or short-stay guest. The Maria suits a long-term tenant or an aging parent who wants a separate bedroom. The Henry suits a family, two roommates or a homeowner who plans to downsize into the ADU and rent the main house.
| | The Paul | The Maria | The Henry | |---|---|---|---| | Starting price | from $148,000 | from $168,000 | from $218,000 | | Size | 321 sq ft | 409 sq ft | 549 sq ft | | Layout | Studio, 1 bath | 1 bedroom, 1 bath | 2 bedroom, 1 bath | | Best for | Solo tenant, guest suite, home office | Long-term rental, parent or adult child | Small family, roommates, downsizing owner | | Backyard impact | Smallest footprint | Moderate | Largest footprint | | Warranty | Tarion | Tarion | Tarion |
You can view floor plans and photos for all three on the ADU models page.
The Paul — 321 sq ft, from $148,000
The Paul is the smallest and least expensive of the three, at 321 sq ft with an open studio layout and one bathroom. It is the model to choose when lot space is tight, when the rear yard is shallow, or when the unit is primarily for a single person.
Typical uses in London: a rental for a Western or Fanshawe student, a guest suite for visiting family, or a self-contained home office with a full bathroom. Because it is a studio, the sleeping area shares space with the living and kitchen zone — good for one person, cramped for two.
The Maria — 409 sq ft, from $168,000
The Maria adds a separate, walled bedroom in 409 sq ft for $20,000 more than The Paul. That single wall changes the tenant pool significantly: a closed bedroom door is what most long-term renters and most older parents actually want.
This is the model we discuss most often with homeowners planning multigenerational living. A parent gets privacy and a real bedroom; the family keeps proximity. It is also the most common configuration for homeowners targeting a stable, year-round rental rather than short stays.
The Henry — 549 sq ft, from $218,000
The Henry is the largest model at 549 sq ft with two bedrooms and one bathroom, starting at $218,000. It is the only one of the three that comfortably houses a couple with a child, two unrelated tenants, or a homeowner who intends to move into the ADU and rent out the main house.
The trade-off is land. A 549 sq ft footprint plus required setbacks and any amenity-space requirement consumes meaningfully more of a standard London backyard than The Paul does. Before committing to The Henry, confirm your lot coverage and setback numbers with the City — those are the constraints that most often push a homeowner down a size.
What is included in the starting price?
Every model's starting price covers the complete structure and a finished, move-in-ready interior — finishes, windows and doors, a ductless heat pump, appliances, quartz counters, vinyl plank flooring, planning and building permits, and Tarion coverage. Site and servicing work sits outside it: sewer and water connections, electrical service upgrades, trenching and excavation, and municipal connection fees. Those are dictated by your lot, not by the model. The full itemized breakdown is on the ADU models page.
This is why a detached ADU in London realistically lands anywhere in the $148,000 to $350,000+ range. A unit 20 feet from an existing service stack on a flat, accessible lot is a very different project from one 90 feet back, behind a mature maple, with a 100-amp panel that needs upgrading. We quote servicing after a site visit, not before — anyone who prices trenching over the phone is guessing.
Municipal connection and permit fees in London change from year to year, and the City has at times waived or reduced certain fees to hit housing targets. Check the current fee schedule with the City of London before you budget, and ask us to include the fees in writing in your quote.
How do the detached models compare to other ADU options?
A detached model is one of four ways to add a unit — the others being an interior or basement conversion, a garage conversion, or an addition to the existing house — and those alternatives are often cheaper but less flexible.
Basement and garage conversions cost less and finish faster, but they consume space you already use and rarely carry a new-home warranty. Detached units cost more, take longer, and give you a genuinely separate address with its own entrance, yard access and — on our models — Tarion coverage. For a fuller breakdown of the four options, see our complete ADU guide.
Why pre-designed models cost less than custom
Pre-designed models are cheaper because the drawings, engineering and material list are already done. Custom design work, structural review and one-off material orders are where budgets drift on backyard projects. London has itself moved toward pre-approved design catalogues to speed up small-home approvals — the same logic that makes The Paul, The Maria and The Henry quotable at a fixed starting price.
That said, pre-designed does not mean unchangeable. Finishes, exterior cladding and some interior configuration can be adjusted. Structural changes to the footprint move the project toward custom pricing, and we'll say so plainly when you ask.
Frequently asked questions
Do I need a building permit for an ADU in London, Ontario?
Yes. Every additional residential unit in London requires a building permit, and detached garden suites also require zoning compliance review for setbacks, lot coverage, height and servicing. Permits are included in our published starting prices; municipal connection fees are not. Confirm current requirements and fees directly with the City of London, as the rules for additional residential units have been amended repeatedly in recent years.
How long does a detached ADU take to build?
A detached standalone unit typically takes 4 to 8 months of construction. Permitting and design run before that and vary with municipal review times, so plan on the full project spanning longer than the build window alone. Basement and garage conversions are faster, generally 2 to 4 months.
Which model gives the best rental return in London?
The Maria and The Henry generally attract a broader tenant pool than The Paul, because separate bedrooms suit long-term renters. Rental rates in London vary by neighbourhood, proximity to Western University and Fanshawe College, and unit condition — check current local listings rather than relying on a general figure. We do not provide rent projections; a local realtor or property manager can give you defensible numbers.
Is the Tarion warranty included on all three models?
Yes. Tarion warranty coverage applies to Kuzyn's detached units, which includes The Paul, The Maria and The Henry. Interior conversions, garage conversions and additions are not covered by Tarion, since Tarion applies to new home construction. Ask us to confirm coverage specifics in writing for your project.
Next step
Kuzyn Builds is family-owned, based in London, and has completed 80+ projects across more than a decade in Ontario, serving London, St. Thomas, Strathroy, Sarnia, Grand Bend and surrounding areas. If you're weighing models, the fastest way forward is a site visit: we measure the lot, check servicing distance, and tell you which of the three actually fits — including when the answer is "none of them, do the basement instead."
Compare the models side by side on the ADU models page, review what to look for in a builder in our London ADU builders guide, or see our full services.
Ready for real numbers on your lot? Book a free consultation or call +1-519-694-4776.