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Serving the Municipality of Strathroy-Caradoc — Strathroy, Mount Brydges & Middlesex County
Modular Homes & Garden Suites in Strathroy-Caradoc, Ontario
Factory-direct modular homes and backyard garden suites for the Municipality of Strathroy-Caradoc: the town of Strathroy, the village of Mount Brydges and the farms of the former Caradoc Township, west of London. Strathroy-Caradoc's Zoning By-law 43-08 calls a garden suite an "additional residential unit" (an ADU), and since By-law 22-26 (March 2026) it allows one in a separate building beside a house in the residential zones and on farm and rural lots. Here's what the by-law allows, what it costs, and the rules that apply.
What you can build in Strathroy-Caradoc
Full modular homes — from $175,696. 29 models from 560 to 1,405 sq ft, 1–3 bedrooms — factory-built to the Ontario Building Code and set on a permanent foundation (a real, permanent house, not a “trailer”).
Backyard suites (ADUs) — from $96,244. 7 compact models built for garden-suite and in-law-suite use, sized to fit what Strathroy-Caradoc's by-law allows.
All homes are CSA-certified (A277 modular / Z240MH manufactured), finished in the factory, and delivered ready for foundation and hook-up. What's the difference between modular, manufactured, and mobile? →
Find your backyard suite — 3 quick questions
We'll narrow the models that fit a typical Strathroy-Caradoc backyard allowance to the ones that fit your life. No email needed.
1 · Who's it for?
2 · What layout?
3 · What size feels right? (Strathroy-Caradoc lots typically allow up to ~800 sq ft)
On a Strathroy or Mount Brydges lot with municipal water and sewer, the suite rules set no fixed size cap: up to 7 m tall, with all buildings covering no more than 55% of the lot. The by-law's older accessory-building rule may still cap the building at 80% of your home's ground floor and 15% of the lot, and the Municipality hasn't confirmed which applies, so design to the smaller figure for now. On a well or septic lot it's up to 75% of your home's floor area, capped at 120 m² (≈1,292 sq ft) for larger homes. Enter your address for the specifics. Your exact lot may allow more or less — get the real number for your address in seconds.
Check your exact Strathroy-Caradoc address →Can you put a garden suite (ADU) in your Strathroy-Caradoc backyard?
Yes, beside a house in the R1, R2 and R3 residential zones and on Rural Residential, General Agricultural and Agricultural Small Holdings lots. The by-law allows up to three units on a serviced lot and two on a well or septic lot. The specifics, from Municipality of Strathroy-Caradoc Comprehensive Zoning By-law 43-08, §4.6(4) Additional Residential Units, as replaced by By-law 22-26 (passed March 16, 2026; May 2026 consolidation):
| Where it goes | Beside a single detached, semi-detached or street townhouse house in the R1, R2 and R3 residential zones, and (up to two units) in the Rural Residential (R5), General Agricultural (A1) and Agricultural Small Holdings (A2) zones. Not in the Lifestyle Community (R4) zone, the A3 zone, or the commercial, industrial, institutional and open-space zones, and not on regulated natural hazard lands without the conservation authority’s permission. |
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| Max size | Serviced lots (Strathroy, Mount Brydges): no fixed cap in the suite rules; all buildings together may cover 55% of the lot. The older accessory-building rule (§4.2(2)) may still cap the building at 80% of your home’s ground floor and 15% of the lot; the Municipality hasn’t confirmed which applies. Well or septic lots: up to 75% of your home’s floor area, and no more than 120 m² (≈1,292 sq ft) if your home’s ground floor is over 139 m². |
| Height | 7.0 m (≈23 ft), to the peak on a well or septic lot. |
| Setbacks | 1.2 m (≈4 ft) from the interior side and rear lot lines, your zone’s exterior side-yard setback on a corner lot, and 2.0 m (≈7 ft) from any other building with a dwelling. Not in the front or exterior side yard. On a well or septic lot, within 30 m (≈98 ft) of the house. |
| Units per lot | Serviced: up to three additional units, up to two in one accessory building. Well or septic: up to two, only one in an accessory building. |
| Parking | One space per suite, which can be tandem (behind another car), on top of the house’s own requirement. |
| Servicing | Municipal water and sewer in Strathroy and Mount Brydges. On a well or septic lot, a qualified professional’s well and septic evaluation must show both can serve the suite; sharing the house’s systems is preferred, a second septic needs a nitrate study, and the suite uses the house’s driveway and meets the MDS I livestock setbacks. |
| Conservation | St. Clair Region, Lower Thames Valley and Upper Thames River conservation authorities each regulate part of the municipality. Building in a regulated area (flood plains, valleys, wetlands) needs that authority’s permit. |
Check your specific Strathroy-Caradoc address →
Garden suite, laneway suite, in-law suite, ARU, ADU — different names for the same thing: a small, self-contained home in the backyard. New to the idea? Start with prefab garden suites for Ontario — what one costs in Strathroy-Caradoc, and the models that fit →
Strathroy-Caradoc's by-law is verified in our checker, so you can check if a garden suite is allowed at your Strathroy-Caradoc address in about a minute.
Getting your building permit in Strathroy-Caradoc
An eligible lot still needs a building permit before anything is delivered. Here's how Strathroy-Caradoc's process actually works — verified against the Strathroy-Caradoc building department's own pages.
How do you apply for an ADU building permit in Strathroy-Caradoc?
Through Cloudpermit (Municipality of Strathroy-Caradoc) (application portal ↗). Apply online through Cloudpermit: create an account, start an application, find your property on the map, choose Building Permit and the Residential project type, then add the applicant and the property owner and upload each document. Paper applications can be submitted at the Municipal Office (52 Frank Street, Strathroy) with the permit package from the Building Department page. Questions: Building Department, 519-245-1105. Strathroy-Caradoc's building-permit page ↗
- Confirm zoning with the Planning Department (519-245-1105, planning@strathroy-caradoc.ca): a detached additional residential unit is permitted beside a house in the R1, R2, R3, R5, A1 and A2 zones under Zoning By-law 43-08 §4.6(4), on lots outside regulated natural hazard lands
- On a well or septic lot, have a qualified professional evaluate the well and septic to show both can serve the suite; sharing the house's systems is preferred, and a second septic system needs a nitrate study (§4.6(4))
- If your lot is in an area regulated by St. Clair Region, Lower Thames Valley or Upper Thames River Conservation Authority, get that authority's permit first
- Have a BCIN-qualified designer prepare the drawings for an Ontario Building Code Part 9 (house-class) building, with a site plan showing every building and its setbacks
- Submit through Cloudpermit, then sign off and submit the application; respond to any plan-review comments and pay the fees
- Book inspections as the permit lists them; a third or later inspection of defective or incomplete work costs extra
What does an ADU permit application in Strathroy-Caradoc need?
- Application for a Permit to Construct or Demolish (the provincial form), with the applicant and the property owner named
- Schedule 1 designer information, and a letter of authorization if an agent applies
- Site plan showing the lot dimensions, every existing and proposed building, the setbacks to the lot lines and, on a private lot, the well and septic system
- Construction drawings for the suite (floor plans, foundation, wall and roof sections, elevations) by a BCIN-qualified designer
- Well and septic evaluation by a qualified professional, and a nitrate study where the suite gets its own septic (private lots)
- Conservation authority permit where the lot is in a regulated area
How much does an ADU building permit cost in Strathroy-Caradoc?
Estimate for a ~600 sq ft detached suite: either $2,694.14 if the Building Department bills it as a new dwelling unit ('Single House, Semi-detached, duplex', with $0.85 per sq ft added only above 2,000 sq ft), or about $429 if it's billed as an accessory building ($344.00 plus $0.85 per sq ft over 500 sq ft), under the 2026 Schedule of Fees and Charges (By-law 131-25). Add $570 for a new septic system on a private lot and the $86 basic plumbing fee. Confirm the category and current-year figures with the Building Department before you budget.
| Building permit, new dwelling unit (2026) | $2,694.14 per dwelling unit, plus $0.85 per sq ft above 2,000 sq ft (Single House, Semi-detached, duplex) |
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| Building permit, accessory building (2026) | $344.00, plus $0.85 per sq ft above 500 sq ft (detached garage, shed, other accessory building). Which line applies to a suite is for the Building Department to confirm |
| New septic system (private lots) | $570.00 flat ($344.00 for a repair) |
| Plumbing and connections | $86.00 basic plumbing fee; $344.00 for new sewer or water connections |
| Re-inspection | $229.00 for a third or later inspection of defective or incomplete work, paid before it's scheduled |
The Development Charges Act exempts one unit in a building ancillary to a house, on any lot, and Strathroy-Caradoc's development-charges pamphlet lists buildings exempt under the Act. A qualifying suite should owe no development charge; check any quoted charge against the Act before you budget.
How long does an ADU building permit take in Strathroy-Caradoc?
Ontario's Building Code requires a decision on a complete house-class application within 10 business days. A detached suite is Ontario Building Code Part 9 (house class), so the legislated review window is 10 business days for a complete application. A lot in a conservation authority's regulated area needs that permit first, which adds time.
Worth knowing before you apply
- The fee category matters: billed as a new dwelling a 600 sq ft suite is about $2,694, as an accessory building about $429. Ask the Building Department which applies before you budget
- On a well or septic lot the gate is the qualified professional's well and septic evaluation; a second septic system also needs a nitrate study
- Three conservation authorities regulate parts of Strathroy-Caradoc (St. Clair Region, Lower Thames Valley, Upper Thames River); a suite isn't allowed on regulated natural hazard lands without that authority's permission
- A CSA A277 modular suite or house: confirm with the Municipality how the zoning by-law treats it before ordering, since the by-law lists modular and mobile homes separately
- A credit-card surcharge of 2% applies to permit fees over $1,000
Fees and timelines are estimates from Strathroy-Caradoc's published schedules, verified October 22, 2026. Rates and processes change — always confirm current requirements with the building department before you apply.
Grants & financing in Strathroy-Caradoc
Development charges — exempt for a qualifying garden suite — Strathroy-Caradoc charges development charges on a new house, but the Development Charges Act exempts one unit in a building ancillary to a house, on any lot, and the Municipality's pamphlet lists buildings exempt under the Act. A qualifying garden suite should owe none; check any quoted charge against the Act before you budget.
See every program → Ontario ADU Grants Directory
A modular or prefab home on a permanent foundation is financed like any house. CMHC Prefab Plus allows an insured mortgage with as little as 5% down on the first $500,000, with construction funds released in stages. How modular home financing works →
Thinking of the suite as a rental? Run the numbers →
Strathroy-Caradoc modular homes — FAQ
Can you build a garden suite in Strathroy-Caradoc?
Yes. Since By-law 22-26 (March 2026), Strathroy-Caradoc's Zoning By-law 43-08 allows an additional residential unit, a garden suite, in a separate building beside a house in the R1, R2 and R3 residential zones of Strathroy and Mount Brydges, and on Rural Residential and agricultural (A1, A2) lots. A serviced lot can have up to three additional units; a well or septic lot up to two.
How big can a garden suite be in Strathroy-Caradoc?
On a lot with municipal water and sewer the suite rules set no fixed size cap: up to 7 m (≈23 ft) tall, with all buildings covering no more than 55% of the lot. The by-law's older accessory-building rule may still cap the building at 80% of your home's ground floor and 15% of the lot, and the Municipality hasn't yet confirmed which applies, so design to the smaller figure. On a well or septic lot it's up to 75% of your home's floor area, and no more than 120 m² (≈1,292 sq ft) if your home's ground floor is over 139 m².
Can you build a garden suite on a well and septic in Strathroy-Caradoc?
Yes, on Rural Residential and agricultural lots. A qualified professional's well and septic evaluation has to show both can serve the suite; sharing the house's systems is preferred, and a second septic system needs a nitrate study. The suite sits within 30 m of the house, uses its driveway, and meets the provincial Minimum Distance Separation setbacks from livestock barns. A new septic permit is $570 in 2026.
Can you put a modular home in Strathroy-Caradoc, Ontario?
The zoning by-law defines a CSA A277 modular home and a CSA Z240 mobile home separately from a single detached house, and lists them only in the Lifestyle Community (R4) zone. We've asked the Municipality to confirm that an A277 modular home counts as a single detached house on an ordinary lot; until then, confirm with the Planning Department (519-245-1105) before you order. Building permits are applied for online through Cloudpermit.
How much does a modular home or backyard suite cost in Strathroy-Caradoc?
Modular home models start at $175,696 and run to about $338,000 for the largest layouts; backyard ADU models start at $96,244. Site work, foundation, delivery, and permits are additional.
Can I get a mortgage on a modular home in Strathroy-Caradoc?
Yes — on a permanent foundation it is financed as real property, including via CMHC Prefab Plus (5% down on the first $500,000).
Local rules summarized from Municipality of Strathroy-Caradoc Comprehensive Zoning By-law 43-08, §4.6(4) Additional Residential Units, as replaced by By-law 22-26 (passed March 16, 2026; May 2026 consolidation); verified by Modular Homes 400 and reviewed by James Clarke, REALTOR®. Always confirm current requirements with the municipality before you build.