Home/Modular Homes by City/St. Catharines
Serving St. Catharines & Niagara Region
Modular Homes in St. Catharines, Ontario
Factory-direct modular homes and backyard suites for St. Catharines and the Niagara Region. Here's what St. Catharines's accessory-dwelling-unit by-law allows in your backyard, what it costs, and the rules that apply.
What you can build in St. Catharines
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 St. Catharines'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 St. Catharines 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? (St. Catharines lots typically allow up to ~860 sq ft)
St. Catharines caps a detached suite at 80 m² (≈860 sq ft); on smaller lots the 10% accessory-coverage limit often binds first. Your exact lot may allow more or less — get the real number for your address in seconds.
Check your exact St. Catharines address →Can you put a garden suite (ADU) in your St. Catharines backyard?
Often, yes — St. Catharines permits a detached Additional Residential Unit on most serviced residential lots. The specifics, from City of St. Catharines Zoning By-law 2013-283 s.2.2.1 (added by By-law 2024-032, April 2024):
| Max size | 80 m² (≈860 sq ft). On smaller lots the 10% accessory-building lot-coverage cap (all accessory structures combined) often binds first. |
|---|---|
| Max height | 4.5 m (≈15 ft) to the top of walls, up to 6.0 m (≈20 ft) to a gable/dormer peak |
| Setbacks | 1.2 m (≈4 ft) rear & side · 3.0 m (≈10 ft) separation from the main house. Not permitted in the front yard. |
| Units per lot | Up to 2 ADUs (both may be detached, or one inside + one detached). Also permitted in the agricultural zones where Section 13 allows. |
| Parking | 0.5 space per ADU (tandem permitted) — one space can cover two ADUs |
| Servicing | Municipal water & sewer |
| Conservation | Niagara Peninsula Conservation Authority (NPCA) on floodplain / watercourse / hazard lands |
Grants & financing in St. Catharines
St. Catharines CIP ADU Grant — Up to 70% of costs (max ~$80,000 for a detached ADU) for properties in the Urban Area Community Improvement Plan — an incentive, not a requirement.
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 →
St. Catharines modular homes — FAQ
Can you put a garden suite in St. Catharines?
Yes. St. Catharines permits up to two accessory dwelling units per lot (with a detached, semi, or townhouse dwelling) — subject to the size, height, and setback rules and a building permit.
How big can a garden suite be in St. Catharines?
Up to 80 m² (≈860 sq ft), though on smaller lots the 10% accessory-coverage cap often binds first. Check your address for the exact number.
Can you put a modular home in St. Catharines?
Yes. On land you own, a modular home on a permanent foundation is legal residential housing under the Ontario Building Code throughout St. Catharines, subject to standard zoning and permits.
How much does a modular home or backyard suite cost in St. Catharines?
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 St. Catharines?
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 City of St. Catharines Zoning By-law 2013-283 s.2.2.1 (added by By-law 2024-032, April 2024); verified by Modular Homes 400 and reviewed by James Clarke, REALTOR®. Always confirm current requirements with the City of St. Catharines before you build.