ADU & GARDEN SUITE BUILDER · ST. THOMAS, ONTARIO
ADU Builders in St. Thomas, Ontario — from $148,000
Kuzyn Builds designs and builds accessory dwelling units in St. Thomas, about 30 km south of our London office. Detached models start at $148,000 with planning and building permits included and Tarion warranty coverage. Most builds run 2 to 8 months from permit approval.
Building an ADU in St. Thomas
St. Thomas has absorbed a decade of London spillover demand and a large employment project on its edge, which puts steady pressure on rental supply. Lots in the older residential grid tend to be deep and already serviced, which is the combination a detached ADU wants.
Who approves it
City of St. Thomas issues zoning approval and the building permit for St. Thomas (Elgin County).
Ontario permits up to three residential units on most serviced residential lots as of right, without a zoning amendment. The province sets that baseline; your municipality still sets setbacks, height, lot coverage, parking and servicing, and still issues the building permit.
Published starting prices
The same prices apply in St. Thomas as in London. These are the base prices for the pre-designed detached models, before site-specific servicing.
| Model | Size | Layout | Starting price |
|---|---|---|---|
| The Paul | 321 sq ft | Studio, 1 bath | $148,000 |
| The Maria | 409 sq ft | 1 bed, 1 bath | $168,000 |
| The Henry | 549 sq ft | 2 bed, 1 bath | $218,000 |
What the price includes
- Complete ADU structure and construction
- Interior finishes and fixtures
- Windows and doors
- HVAC system (ductless heat pump)
- Appliances (fridge, stove, dishwasher, microwave)
- Quartz countertops
- Vinyl plank flooring
- Planning and building permits
- Tarion warranty (detached units only)
Additional Costs (Not Included in Base Price): Sewer line connections and hookups; Water line connections and hookups; Electrical service connections and upgrades; Distance from main utility lines; Local permit and connection fees; Site-specific excavation and trenching; Municipal connection fees.
Travel outside London is quoted as a visible line rather than buried in the base price, so you can see what the distance actually costs.
Why St. Thomas homeowners choose Kuzyn Builds
- Published fixed starting prices, from $148,000 — not "request a quote to find out".
- Planning and building permits included in the base price.
- Tarion warranty coverage on detached models.
- Named, pre-designed models you can compare before you commit: The Paul, The Maria, The Henry.
- Family-owned and London-based, with 80+ completed projects over 10+ years in Ontario.
Frequently asked questions
Does Kuzyn Builds build ADUs in St. Thomas?
Yes. St. Thomas is about 30 km south of our London office and is inside our regular service area, alongside London, St. Thomas, Strathroy, Sarnia and Grand Bend. The same pre-designed detached models and the same published starting prices apply, from $148,000.
How much does an ADU cost in St. Thomas?
The pre-designed detached models start at $148,000 for The Paul (321 sq ft), with planning and building permits included. Interior and garage conversions start lower, from about $75,000. The variable between one lot and the next is site servicing — water, sanitary and hydro runs — which is why a property assessment comes before a firm number.
Who approves an ADU in St. Thomas?
The City of St. Thomas issues the zoning approval and the building permit. Ontario permits up to three residential units on most serviced residential lots as of right, without a zoning amendment. The province sets that baseline; your municipality still sets setbacks, height, lot coverage, parking and servicing, and still issues the building permit.
How long does a St. Thomas ADU take to build?
Between 2 and 8 months from permit approval to completion, depending on configuration. Interior and garage conversions run 2 to 4 months; a detached standalone unit runs 4 to 8 months. Permit approval sits ahead of that and depends on the municipality's queue.
Other areas we build in
Thinking About an ADU in St. Thomas?
No sales pitch — a straight conversation about your lot, your budget and whether an ADU makes sense.