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Serving the Municipality of North Middlesex & Middlesex County
Modular Homes in North Middlesex, Ontario
Factory-direct modular homes and backyard suites for the Municipality of North Middlesex — Ailsa Craig, Parkhill, Nairn, and the former East Williams, West Williams and McGillivray townships, northwest of London. New for 2026: North Middlesex's HAF zoning amendment (By-law 020 of 2026, passed February 2026) permits a detached additional residential unit as-of-right across the residential, hamlet and agricultural zones — on municipal services in the villages or on a private well & septic in the country. Here's what the by-law allows, what it costs, and the rules that apply.
What you can build in North Middlesex
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 North Middlesex'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 North Middlesex 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? (North Middlesex lots typically allow up to ~1,000 sq ft)
On a fully-serviced Ailsa Craig or Parkhill lot a detached suite has no fixed size cap (governed by the 55% lot-coverage and 7.0 m height limits, up to 3 units/lot). On a private well+septic lot it’s up to 75% of your home’s floor area, capped at 120 m² (≈1,292 sq ft), with a required septic evaluation. Ailsa Craig (Ausable River) and Parkhill (Parkhill Creek) have mapped floodplains to check — 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 North Middlesex address →Can you put a garden suite (ADU) in your North Middlesex backyard?
Often, yes — North Middlesex permits a detached Additional Residential Unit on most serviced residential lots. The specifics, from Municipality of North Middlesex Zoning By-law 35 of 2004, §6.51–6.53 (added as-of-right by the HAF amendment, By-law 020 of 2026, passed February 4, 2026):
| Max size | Serviced (Ailsa Craig/Parkhill): no fixed cap — governed by 55% lot coverage + 7.0 m height. Private well+septic: up to 75% of your home’s floor area, capped at 120 m² (≈1,292 sq ft) where the home’s ground floor exceeds 140 m² |
|---|---|
| Max height | 7.0 m (≈23 ft), measured grade to peak, when the suite is in an accessory building |
| Setbacks | 1.5 m (≈5 ft) from the interior side and rear lot lines · exterior side yard as per your zone · 2.0 m (≈7 ft) from any other building with a dwelling. Not permitted in the front or exterior side yard |
| Units per lot | Serviced: up to 3 additional units (up to 2 in one accessory building). Private well+septic: up to 2 additional units, only one detached |
| Parking | 1 additional space per suite, on top of your home’s required parking (tandem allowed) |
| Where allowed | As-of-right in the village Residential (R1/R2/R3), Hamlet Residential (RH) and Agricultural (A1/A2/A3/AG1) zones — not in the commercial, industrial or institutional zones |
| Servicing | Municipal water & sewer in Ailsa Craig / Parkhill (connect to the existing service), or a private well & septic in the country with a qualified septic evaluation. Rural/agricultural lots also meet MDS I and sit within 30 m of the home |
| Conservation | Ausable Bayfield CA (ABCA) — Ailsa Craig on the Ausable River, Parkhill on Parkhill Creek; both village floodplains bar development pending an Environmental Impact Study + ABCA approval |
Getting your building permit in North Middlesex
An eligible lot still needs a building permit before anything is delivered. Here's how North Middlesex's process actually works — verified against the North Middlesex building department's own pages.
How do you apply for an ADU building permit in North Middlesex?
Through Municipality of North Middlesex Building Department (application to the Chief Building Official). Confirm the current submission method (online portal / email / in-person) and current-year fees with the North Middlesex Building Department before applying — the Municipality reviews a permit only once the application is complete. North Middlesex's building-permit page ↗
- Confirm zoning with Planning first — a detached additional residential unit is now as-of-right (By-law 020 of 2026) in the residential, hamlet and agricultural zones, but confirm your lot's servicing (municipal vs private) and floodplain status before you design
- Retain a qualified BCIN designer for the Ontario Building Code Part 9 (house-class) construction drawings
- On a private well+septic lot, have a licensed septic designer provide a septic evaluation + design showing the existing (or new) system can serve the added unit under OBC Part 8
- If your lot is in the Ausable River (Ailsa Craig) or Parkhill Creek (Parkhill) floodplain or a regulated area, obtain an Ausable Bayfield Conservation Authority (ABCA) permit before the building permit
- Submit the complete building permit application + drawings to the North Middlesex Building Department
- Respond to any plan-review comments, pay all fees, then book inspections
What does a North Middlesex ADU permit application need?
- Completed building permit application + Schedule 1 (Designer Information)
- Site plan showing all structures, setbacks to the lot lines, and (on a private lot) the septic system and well
- Construction drawings (floor plans, elevations, sections) and an HVAC / heat-loss plan, prepared by a BCIN designer
- Septic evaluation + design for a private-serviced lot (OBC Part 8)
- Lot grading plan
- Ausable Bayfield Conservation Authority (ABCA) permit/clearance if the lot is in a regulated floodplain or hazard area
- Letter of authorization if the applicant is not the owner
How much does an ADU building permit cost in North Middlesex?
Estimate for a ~800 sq ft detached suite on private septic: roughly $2,646–$2,769 for the building permit (Group C dwelling unit — the base fee, since a suite under 2,000 sq ft adds no per-sq-ft charge) plus about $577 for a new septic system, an $87 basic plumbing fee, and a $57 service-connection inspection. Figures from North Middlesex Fees & Charges By-law 109 of 2025 (Schedule C — Building Department, 2026), plus HST where applicable — confirm current-year figures and the exact ADU classification with the Building Department.
| Building permit — dwelling unit (Group C) | Single/semi/duplex $2,769, or multiple-unit dwelling $2,646 per dwelling unit, each plus $1.00/sq ft only above 2,000 sq ft (By-law 109 of 2025 §3.0.3) — a detached suite under 2,000 sq ft pays the base fee; the Chief Building Official sets the exact class |
|---|---|
| New septic system | $577 for a new sewage disposal system ($346 for a repair) (§3.1.3–3.1.4) |
| Plumbing | $87 basic plumbing fee (§3.1.6); $57 per sewer/storm/water connection inspection (§3.1.5) |
| Re-inspection | $231 for a 3rd or additional inspection of defective/incomplete work, paid before scheduling (§3.4.2) |
Under the Development Charges Act as amended by Bill 23 (More Homes Built Faster), a qualifying additional residential unit ancillary to the principal dwelling is exempt from municipal development charges — confirm the treatment for your specific project with the Municipality (North Middlesex's DC By-law 112 of 2025 sets the rates for new principal dwellings).
How long does an ADU building permit take in North Middlesex?
Ontario's Building Code requires a decision on a complete house-class application within 10 business days. A detached additional residential unit is OBC Part 9 (house class), so the legislated review window is 10 business days for a complete application; a lot in an ABCA regulated area needs the conservation-authority approval first, which adds time.
Worth knowing before you apply
- North Middlesex charges a relatively high flat base building-permit fee for a dwelling unit (~$2,646–$2,769 for a suite under 2,000 sq ft) — budget for it up front, plus HST
- On a private well+septic lot the binding gate is a licensed professional's septic evaluation showing the system can handle the added unit (OBC Part 8); the new-septic permit itself is $577
- Ailsa Craig (Ausable River) and Parkhill (Parkhill Creek) have mapped floodplains — a lot in a regulated area needs an Ausable Bayfield Conservation Authority (ABCA) permit before the building permit, and development is barred in the floodplain pending an Environmental Impact Study
- A qualifying additional residential unit is exempt from municipal development charges (Bill 23) — a real saving versus a new principal dwelling
- Confirm the current permit submission method (online portal / email / in-person) with the Building Department — it isn't published in the by-laws provided
Fees and timelines are estimates from North Middlesex's published schedules, verified July 8, 2026. Rates and processes change — always confirm current requirements with the building department before you apply.
Grants & financing in North Middlesex
Development-charge relief for additional units — Under the Development Charges Act (Bill 23), a qualifying additional residential unit ancillary to your home is generally exempt from municipal development charges — confirm the current treatment with the Municipality for your project.
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 →
North Middlesex modular homes — FAQ
Can you build a garden suite / ADU in North Middlesex (Ailsa Craig, Parkhill…)?
Yes. Since the HAF zoning amendment (By-law 020 of 2026, February 2026) North Middlesex permits a detached additional residential unit as-of-right in its residential, hamlet and agricultural zones — subject to the size, height and setback rules and a building permit. Note that a temporary, portable "garden suite" is a separate instrument (a Temporary Use By-law, up to 20 years); the permanent additional residential unit is the as-of-right path.
How big can a backyard suite be in North Middlesex?
It depends on servicing. On a fully-serviced Ailsa Craig or Parkhill lot there’s no fixed floor-area cap — the 55% lot-coverage limit and the 7.0 m height limit govern, and up to 3 additional units are allowed per lot. On a private well+septic lot the detached suite is capped at 75% of your home’s floor area, or 120 m² (≈1,292 sq ft) where your home’s ground floor is over 140 m² — up to 2 units, one detached. Enter your address for the specifics.
Can you build an ADU on well and septic in North Middlesex?
Yes. Rural North Middlesex lots on a private well and septic can add a detached suite, with a qualified professional’s septic evaluation showing the system can serve the added unit (and the well supply is adequate). The suite must sit within 30 m of your home, share the driveway, and meet the provincial Minimum Distance Separation setbacks from livestock.
Can you put a modular home in North Middlesex, Ontario?
Yes. On land you own, a modular home on a permanent foundation is legal residential housing under the Ontario Building Code throughout North Middlesex — as the principal dwelling or, on an eligible lot, as an additional residential unit.
How much does a modular home or backyard suite cost in North Middlesex?
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 North Middlesex?
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 North Middlesex Zoning By-law 35 of 2004, §6.51–6.53 (added as-of-right by the HAF amendment, By-law 020 of 2026, passed February 4, 2026); verified by Modular Homes 400 and reviewed by James Clarke, REALTOR®. Always confirm current requirements with the City of North Middlesex before you build.