Basements, Additions & Outdoor · Oshawa
Garden Suites & Detached ADUs in Oshawa
Detached additional dwelling units, garden suites and coach houses built behind the main house, from zoning check to occupancy.
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Oshawa, Durham Region
Garden Suites & Detached ADUs in Oshawa
More Oshawa families are building garden suites: a separate small home in the backyard for a parent, an adult child or a tenant. With post-war bungalows, older downtown homes and newer north-end subdivisions across Downtown Oshawa, Lakeview and Eastdale, the right design depends on the lot, the services and the local zoning.
Garden suites in Oshawa are approved by the City of Oshawa, which sets the setbacks, height, size and lot coverage on top of the Ontario Building Code. We check what your lot allows, coordinate drawings and the permit, plan the water, sewer and electrical connections, and build the suite through to occupancy.
Call (647) 424-1511 or send the form on this page for a free garden suite quote in Oshawa. Tell us what you want to change, add a few photos of the space, and we will book a visit and send a written quote that lists the scope, the materials, the permits involved and the schedule.
Oshawa homes
What garden suites & detached adus involves in Oshawa's houses
Century and heritage homes in Oshawa
Older Oshawa homes often sit on deep, narrow lots, which can suit a garden suite at the back. The catch is usually the services: an old water line or a small electrical service may not carry two homes, so an upgrade is often part of the plan. Where the property is in a heritage area, a visible new building may need heritage review.
Post-war bungalows and back-splits in Oshawa
Oshawa's post-war bungalows often have generous rear yards and a detached garage near the back of the lot. Replacing that garage with a garden suite, or building beside it, is a common approach, and the existing driveway often provides the access path a suite needs.
Newer homes built since 2000 in Oshawa
Newer Oshawa lots tend to be tighter, so rear-yard setbacks and lot coverage decide whether a garden suite fits and how big it can be. The subdivision's grading plan matters too, because a new building must not send water onto neighbouring lots.
Rules in Oshawa
Permits and approvals for garden suites & detached adus in Oshawa
Building permits
Building permits in Oshawa are issued by the City of Oshawa. Electrical work anywhere in Ontario is done by a licensed electrical contractor under an Electrical Safety Authority (ESA) permit. We confirm what your project needs before you sign and book every inspection.
Additional residential units
Since the province's More Homes Built Faster Act (2022), most urban serviced lots in Ontario with a detached house, semi or townhouse can have up to three units: the main home plus two additional units, one of which may be in a separate building. Municipalities still set zoning details, and the province limits how much parking they can require. The City of Oshawa applies these rules locally, and every unit needs a building permit and must meet the Building Code and Fire Code.
Conservation authority
Much of Oshawa falls within the Central Lake Ontario Conservation Authority (CLOCA) watershed. Building near a shoreline, river, floodplain, valley or wetland can need a conservation authority permit before the municipality will issue a building permit. We check the regulation mapping for your property early so it does not hold up the schedule.
Heritage properties
If your Oshawa home is designated under the Ontario Heritage Act or sits in a heritage conservation district, exterior changes generally need heritage approval as well as a building permit. We check your property's status before design starts.
Testing before demolition
Homes built before the 1990s can contain asbestos in plaster, textured ceilings, floor tile, vermiculite insulation and pipe wrap, and homes from before the 1960s often have lead paint. In Oshawa's older houses we test suspect materials before demolition and handle them by the regulations if they are found.
The service
Garden Suites and Detached ADUs, Built Properly
A garden suite, also called a detached additional dwelling unit (ADU), coach house or backyard home, is a separate small house behind the main one. Families build them for aging parents, adult children, or rental income, and they give everyone more privacy than a basement apartment.
Ontario's More Homes Built Faster Act (2022) allows most urban lots on municipal water and sewer with a detached house, semi or townhouse to have up to three units, and one of them can be in a separate building. The municipality still sets the zoning details: how far the suite must be from the lot lines, how tall and how large it can be, and how much of the lot it can cover.
More about garden suites & detached adus →The process
How your Oshawa project comes together
01
Consultation
Tell us what you want to change and send a few photos. We visit, measure and talk through options.
02
Written Quote
A clear scope, materials, permits and schedule, in writing. No vague allowances.
03
Permits & Planning
Drawings, permits and material orders lined up before demolition starts.
04
Build & Walk-Through
Work done in the right order, inspected where required, and walked through with you at the end.
Across Oshawa
Garden Suites & Detached ADUs throughout Oshawa
Oshawa has older homes around downtown and the original auto-plant neighbourhoods, post-war bungalows across the south and east, and newer subdivisions in Windfields, Taunton and Northglen near Durham College and Ontario Tech University.
Questions
Garden Suites & Detached ADUs in Oshawa: FAQs
How do I get a garden suites & detached adus quote in Oshawa?+
Call (647) 424-1511, use the form on this page or email info@ontariorenovationcompany.com. Tell us what you want to change and send a few photos, and we will book a visit and send a written quote for your Oshawa project.
What kinds of Oshawa homes do you work on?+
All of them. Housing in Oshawa includes century and heritage homes, post-war bungalows and back-splits and newer homes built since 2000, and each comes with its own considerations, from older wiring and foundations to builder warranties, septic systems and shoreline rules. We plan the work around the house you actually have.
Do I need a conservation authority permit in Oshawa?+
Only if your property is in a regulated area, such as near a shoreline, river, valley, floodplain or wetland. Much of Oshawa falls within the Central Lake Ontario Conservation Authority (CLOCA) watershed. We check the mapping for your address before applying for the building permit.
Can I build a garden suite on my property?+
On many urban lots in Ontario, yes. Provincial rules allow a third unit in a separate building on most serviced residential lots, but your municipality's zoning sets the setbacks, height, size and lot coverage. We check your lot before any drawings are made.
What is the difference between a garden suite and a basement apartment?+
A basement apartment is inside the main house; a garden suite is a separate building in the yard. Garden suites give both households more privacy and keep the main house intact, but they involve a foundation, a new structure and new service connections.
Does a garden suite need its own water, sewer and hydro?+
It needs all three, usually connected through the main house's services or run from the street. Older services may need to be upgraded to carry two homes. We assess this early because it affects the cost and the layout.
Can I sell the garden suite separately?+
Generally no. An additional residential unit is part of the same property as the main house and is not severed into its own lot.
Do you offer garden suites & detached adus across Oshawa?+
Yes. We work throughout Oshawa, including Downtown Oshawa, Lakeview, Eastdale, McLaughlin, Northglen, Taunton and Windfields, and in nearby Courtice, Ajax, Bowmanville, Pickering and Newcastle.
More renovation services in Oshawa
Alongside garden suites & detached adus, we also handle legal basement apartments, home additions and accessible and aging-in-place renovations in Oshawa, so related work can be planned together.
Other basements, additions & outdoor services in Oshawa: basement finishing, legal basement apartments, home additions and decks & outdoor living.
Further reading
Your Oshawa renovation, done properly.
Tell us what you want to change and send a few photos. We will book a visit and send a clear written quote, with no obligation.