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Garage Conversions in Oshawa, Ontario: design, permit and build on a single contract. A typical 700 sq ft unit estimates at $115,500-$170,500 (about $393/sq ft), with $6,500-$11,500 including Durham Region charges in municipal approvals and a April-November construction season.

Converting an existing detached or attached garage into heated, insulated living space or a fully self-contained coach house unit.
Service area
Oshawa, Ontario
Durham Region
Typical build estimate
$115,500-$170,500
about $393/sq ft in Oshawa
Municipal approvals
$6,500-$11,500 including Durham Region charges
quoted separately from the build
Build season
April-November
134 cm snow · -4.1°C winter avg
Frost depth
1.2 m
footing depth, OBC Part 9
Local market
175,383
residents · walkability 50/100
Oshawa runs a residential rental housing licensing by-law covering the wards around Ontario Tech and Durham College, so in Windfields and Northglen a new secondary suite needs a licence as well as a permit. Owners planning student tenancy get the licensing test folded into the design brief, because it sets bedroom count and parking. Oshawa permits additional dwelling units and operates a rental-housing licensing regime in the university district that a new suite must satisfy.
Older large-lot neighbourhoods near downtown, plus student-rental territory around Ontario Tech and Durham College where licensing applies. Oshawa sees 134 cm of snow and -4.1°C winter averages.
A garage was never built to be lived in: the slab sits above frost, the walls are usually uninsulated single-wythe, and the header over the vehicle door carries nothing. Every Oshawa conversion therefore starts with a structural and thermal assessment of what is already standing. The slab is the decisive item - an existing garage slab rarely bears on a 1.2 m footing, so we either underpin the perimeter or pour a new insulated slab inside the existing walls before any framing begins.
Converting the garage removes a parking space, which is why the 50/100 walkability of Oshawa matters more on this form than on any other - it decides whether parking relief is arguable or the driveway has to absorb the loss.
Everything you need to know about our services.
A typical 700 sq ft build in Oshawa estimates at $115,500-$170,500 - about $393/sq ft, set by $6,500-$11,500 including Durham Region charges in approvals, a 1.2 m frost-depth footing requirement and 134 cm of annual snow load. Final pricing follows the site visit.
Related service: Our ADU services
Oshawa permits additional dwelling units and operates a rental-housing licensing regime in the university district that a new suite must satisfy. Approval costs in Oshawa run $6,500-$11,500 including Durham Region charges, quoted separately from construction so the permit stage holds no surprises.
Related service: Our ADU services
Older large-lot neighbourhoods near downtown, plus student-rental territory around Ontario Tech and Durham College where licensing applies. At 50/100 walkability, Oshawa suites usually keep one parking space: enough to clear the zoning review without surrendering the whole yard. We work regularly in O'Neill, McLaughlin, Northglen.
Related service: ADU Building Permit
Rarely as-is. Most Oshawa garage slabs are shallow, uninsulated and poured above the 1.2 m frost line, so they fail both the structural and the thermal requirement for habitable space. We either underpin the perimeter or pour a new insulated slab inside the standing walls - that decision is made at the first site visit and it is the single largest cost variable on this form.
Related service: Our ADU services
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