---
title: "Second-storey additions in Oshawa: height and cost"
url: "https://www.jarviscontracting.ca/second-storey-additions/oshawa"
description: "Second storeys in Oshawa as of October 2026: the 9.0 m height limit and how it's measured, older foundations, the $15.56 per m2 fee and the HST rebate."
publisher: "Jarvis Contracting"
dateModified: "2026-11-02"
---
# Second-storey additions in Oshawa

**Can an older Oshawa bungalow take a second storey under the city's 9.0 m height limit?**

On height, usually yes: the common R1 zones in Oshawa allow 9.0 m, measured from the average grade at the front wall to halfway up a pitched roof, as of October 2026. The harder question is the foundation, which a structural engineer checks before the City of Oshawa building division sees a drawing. (Checked 2026-10-05.)

## Key takeaways

- About 59% of Oshawa's occupied homes in 2021 were built before 1981, more than double Whitby's share, according to [Statistics Canada, 2021 Census](https://www12.statcan.gc.ca/census-recensement/2021/dp-pd/prof/details/page.cfm?Lang=E&DGUIDlist=2021A00053518013).
- Oshawa counted 15,700 occupied homes built in 1960 or earlier and 23,330 built from 1961 to 1980 in the [2021 Census](https://www12.statcan.gc.ca/census-recensement/2021/dp-pd/prof/details/page.cfm?Lang=E&DGUIDlist=2021A00053518013).
- A house can rise 9.0 m in Oshawa's common R1 zones (R1-A to R1-E) and 10.5 m on the larger R1-F to R1-H lots, per the zone table in [By-law 60-94](https://media-002-ca.cdn.govstack.com/oshawa-016-ca/media/xrthfhqx/zoning-by-law-60-94.pdf).
- Oshawa charges $15.56 per m2 for a house addition in 2026 under [By-law 33-2009](https://media-002-ca.cdn.govstack.com/oshawa-016-ca/media/em3h4lr3/bylaw-33-2009-as-amended-by-by-law-118-2025.pdf), so a 75 m2 second floor is a permit fee of about $1,167 (our arithmetic).
- Gutting the main floor while the storey goes on adds a flat $160 interior-gutting fee in Oshawa, and the by-law lets every fee rise 3% each 1 January ([By-law 33-2009](https://media-002-ca.cdn.govstack.com/oshawa-016-ca/media/em3h4lr3/bylaw-33-2009-as-amended-by-by-law-118-2025.pdf)).

## Permits for this work in Oshawa

| Item | What applies | Source | Checked |
|---|---|---|---|
| Where to apply | Oshawa Application Portal (servicecv.oshawa.ca) | [www.oshawa.ca](https://www.oshawa.ca/living-here/building-and-renovating/building-permits/) | 2026-10-05 |
| Addition permit fee | $15.56 per m2 | [media-002-ca.cdn.govstack.com](https://media-002-ca.cdn.govstack.com/oshawa-016-ca/media/em3h4lr3/bylaw-33-2009-as-amended-by-by-law-118-2025.pdf) | 2026-10-05 |
| Conservation authority | Central Lake Ontario Conservation Authority (CLOCA) | [www.oshawa.ca](https://www.oshawa.ca/living-here/building-and-renovating/building-permits/) | 2026-10-05 |
| Zoning by-law | Zoning By-law 60-94 (as amended; consolidation updated 12/01/2025) | [www.oshawa.ca](https://www.oshawa.ca/business-development/planning-and-development/development-applications/zoning/) | 2026-10-05 |
| Minor variance (Committee of Adjustment) fee | $856 per lot | [www.oshawa.ca](https://www.oshawa.ca/business-development/planning-and-development/development-applications/committee-of-adjustment/) | 2026-10-05 |

Fees and rules as published by Oshawa and the agencies linked, checked 6 October 2026. Confirm with the building department before you apply.

## The nearest finished jobs

- [West Lynde: a Whitby bungalow made two storeys in 4.5 months](https://www.jarviscontracting.ca/projects/west-lynde): Whitby, 6 km away, 2023. New second storey of about 800 sq ft with two bedrooms, a walk-in closet and a bathroom; new kitchen, two new bathrooms, floors, stairs and trim below.
- [Greenwood: a new top storey and rear extension in Toronto](https://www.jarviscontracting.ca/projects/greenwood): Toronto, 45 km away, 2026. Top floor replaced with a new storey, rear extension, basement enlarged, full interior design and build.

## What it costs

| Work | Range (CAD) | Basis | Source |
|---|---|---|---|
| Second-storey addition, 600 to 1,200 sq ft | 300000 to 800000 | GTA, 2026. The new floor; a kitchen or bathrooms below add to it. Before 13% HST. | Our 2026 price |

Our 2026 ranges, not quotes: every job is priced after a site visit.

What moves the number:
- Whether the foundation and walls can carry the new floor, or need reinforcing
- A full storey or a partial one
- Whether the main floor is redone at the same time
- The roof design and how it meets what's left
- Engineering, drawings and the permit
- Finish level, and 13% HST on top

## What does Oshawa's older housing mean for building up?

Oshawa has the oldest housing of the five Durham Region, Ontario, towns along the lake, and the most older homes of any Durham municipality. Of 66,630 occupied homes in the [2021 Census](https://www12.statcan.gc.ca/census-recensement/2021/dp-pd/prof/details/page.cfm?Lang=E&DGUIDlist=2021A00053518013), nearly a quarter date from 1960 or before. The census doesn't say how many are bungalows, but it does say an Oshawa house is more likely than not to be 45 years old or more.

A house that age was footed and framed for the load it carries now, not for another floor. So the first visit is about what's underneath. The engineer wants footing width and depth, whether the walls are concrete block or poured, and where new point loads will land. Main-floor ceiling joists usually become the new floor, and joists sized for a ceiling rarely carry a bedroom, so plan on new joists or reinforced ones. If a footing is too small, the fix is underpinning that section or a new footing under a post. Either one changes the budget, so the engineer's visit comes before a firm price.

## How does Oshawa measure the 9.0 m?

From grade to the roof, where "grade" for a building is the average finished ground level along its front wall, per the definitions in [By-law 60-94](https://media-002-ca.cdn.govstack.com/oshawa-016-ca/media/xrthfhqx/zoning-by-law-60-94.pdf). On a gable or hip roof the top point is the average level between eaves and ridge. A flat roof is measured to its highest point, and so is a one-slope roof pitched under 20 degrees. On our reading, a lot that drops away behind the house leaves the back wall standing taller than 9.0 m without breaking the limit, because the measurement starts at the front.

That definition matters for roof shape. We rebuilt a Whitby bungalow as a two-storey house in 2023 with a single-slope roof to stop ice damming; in Oshawa, a single slope under 20 degrees counts to its top edge and uses more of the 9.0 m than a gable would.

## What will the City charge, and what comes back?

Oshawa's 2026 rate is $15.56 per m2 of new floor area, measured to the outer face of the exterior walls, under Schedule B of [By-law 33-2009](https://media-002-ca.cdn.govstack.com/oshawa-016-ca/media/em3h4lr3/bylaw-33-2009-as-amended-by-by-law-118-2025.pdf). A 75 m2 storey is about $1,167, and a 93 m2 one (roughly 1,000 sq ft) is about $1,447 (our arithmetic). Gutting the main floor at the same time adds a $160 flat fee. The by-law lets fees rise 3% each 1 January.

## Can we stay in the house?

Plan to live elsewhere for the roof-off and framing stage. The stair, plumbing stack and ductwork all run up through the old main floor, so the trades are working inside the rooms you'd be living in. Our nearest finished second storey is [West Lynde](https://www.jarviscontracting.ca/projects/west-lynde), about 6 km west in Whitby, where the kitchen and both bathrooms below were redone in the same job.

## How the job runs in Oshawa

1. **Meet James.** James meets you at the house, hears what you want and gives you a rough estimate on the spot. The first estimate is free.
2. **Proposal and contract.** If the estimate works for you, James prepares a detailed proposal. The whole project is priced, and the contract signed with a 10% deposit, before any design work begins.
3. **Design onboarding.** Our designer sends you an onboarding email with some homework: your style, how your family uses the house, and what you need and want. You share Pinterest boards, then go through them together on a Zoom call: what you like in the pictures, and what you don't.
4. **Measure and floor plans.** The designer measures the house and draws the floor plan: which walls come out, where the stairs land, how new space joins the old. We go through it with you until it's confirmed.
5. **Drawings and 3D rendering.** With the plan confirmed, she draws the elevations and the millwork, then puts it all into a 3D rendering, so you see the rooms before anyone orders a cabinet.
6. **Finishes presentation.** We don't take you round the stores: there are too many options. Using what she learned in onboarding, the designer narrows the tile, flooring, quartz, plumbing fixtures and the rest to a few choices that suit your style, collects the samples and presents them to you in our office. If a selection changes the price, the change goes through a change order you sign.
7. **Permits and engineering.** We prepare the permit drawings, bring in the structural engineer wherever a beam or a load changes, and apply to the municipality. If the plan changes after the permit is issued, we file the amendment. In Oshawa, applications go through the town's online permit portal.
8. **Construction.** Our crew and trades build it, with one point of contact from demolition to the last coat of paint. Our site supervisors write a job log every day, which you can follow in our online app. When we open a wall and find a problem, you hear about it, and what it costs, before we fix it.
9. **Inspections.** The municipal building inspector checks the work at each stage the permit sets, before it gets covered up. Inspections are booked with Oshawa's building department.
10. **Handover.** We walk the finished house with you and put right anything that isn't. On one job a stair stain didn't match the new floor, so we refinished the stairs.

## Credentials

- Written warranty: 1 year workmanship and materials, 2 years plumbing, heating, electrical and building envelope, 7 years structural
- BBB Accredited Business: Accredited by the Better Business Bureau since November 2025 (https://www.bbb.org/ca/on/ajax/profile/general-contractor/jarvis-contracting-inc-0107-1416595)
- Durham Region Home Builders' Association: Member, Renovators (https://www.drhba.com/Sys/PublicProfile/99587295/5125036)
- RenoMark: RenoMark renovator, through the DRHBA (https://renomark.ca/find-a-renovator/)

## Questions

### Does a sloping lot in Oshawa change how high my second storey can be?

Yes, a lot that falls toward the back can work in your favour. Oshawa's Zoning By-law 60-94 measures a building's height from the average finished grade along its front wall, not from the lowest ground around it. On a lot that falls toward the back, the rear of a second storey can stand taller than 9.0 m above the backyard while the house stays within the limit as measured at the front (our reading; the City's zoning staff confirm it on your drawings).

### Can a second storey in Oshawa get the HST owner-built rebate?

Often, if it at least doubles the living space. The Canada Revenue Agency names a full second storey on a bungalow as its example of an addition treated as a newly built home. The Ontario new housing rebate then returns up to $24,000 of the provincial HST whatever the house is worth, while the federal rebate only applies under $450,000. A one-room addition doesn't qualify.

### How long does Oshawa take to issue a permit for a second storey?

Ontario's Building Code gives a municipality 10 business days to decide on a complete application for a house with no unit above another, per the 2024 Building Code compendium. The City of Oshawa's building permits page warns that record application volumes mean it can't guarantee review times, so we build slack into the schedule.

### Does Oshawa's heritage district affect a second storey?

Almost never. Oshawa's only Heritage Conservation District, South Field (designated 2021), is airport and park land at 1000 Stevenson Road North, not a residential street, per the city's heritage register. Over 40 Oshawa properties are individually designated; on one of those, a second storey that affects its heritage attributes needs council's written consent under the Ontario Heritage Act.

## Sources

1. [Statistics Canada, 2021 Census Profile, Oshawa](https://www12.statcan.gc.ca/census-recensement/2021/dp-pd/prof/details/page.cfm?Lang=E&DGUIDlist=2021A00053518013)
2. [City of Oshawa, Zoning By-law 60-94](https://media-002-ca.cdn.govstack.com/oshawa-016-ca/media/xrthfhqx/zoning-by-law-60-94.pdf)
3. [City of Oshawa, Building By-law 33-2009, Schedule B (2026 fees)](https://media-002-ca.cdn.govstack.com/oshawa-016-ca/media/em3h4lr3/bylaw-33-2009-as-amended-by-by-law-118-2025.pdf)
4. [Canada Revenue Agency, GST/HST new housing rebate](https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/gst-hst-businesses/gst-hst-rebates/new-housing-rebate.html)
5. [City of Oshawa: Building permits](https://www.oshawa.ca/living-here/building-and-renovating/building-permits/)
6. [City of Oshawa: Zoning](https://www.oshawa.ca/business-development/planning-and-development/development-applications/zoning/)
7. [City of Oshawa: Committee of adjustment](https://www.oshawa.ca/business-development/planning-and-development/development-applications/committee-of-adjustment/)

## How this page was made

Written by Jarvis Contracting. Municipal facts checked 2026-10-06. Fact-checked by Space & Story on 2026-10-05.

## Keep reading

- [Second-storey additions: all areas](https://www.jarviscontracting.ca/second-storey-additions)
- [Building in Oshawa](https://www.jarviscontracting.ca/areas/oshawa)
- [Second-storey additions in Whitby](https://www.jarviscontracting.ca/second-storey-additions/whitby) (6 km away)
- [Second-storey additions in Ajax](https://www.jarviscontracting.ca/second-storey-additions/ajax) (13 km away)
- [Second-storey additions in Clarington](https://www.jarviscontracting.ca/second-storey-additions/clarington) (14 km away)
- [Home additions in Oshawa](https://www.jarviscontracting.ca/home-additions/oshawa)
- [How much does a home addition cost in Ontario in 2026?](https://www.jarviscontracting.ca/guides/home-addition-cost-ontario)
- [How much does a second-storey addition cost in Ontario in 2026?](https://www.jarviscontracting.ca/guides/second-storey-addition-cost-ontario)
- [Is it cheaper to build up or out? 2026 Ontario costs](https://www.jarviscontracting.ca/guides/build-up-or-out)
- [Ontario HST relief for owner-built homes and big renovations, 2026](https://www.jarviscontracting.ca/guides/ontario-hst-relief-substantial-renovation)
- [Should we add on or move? Costs compared for 2026](https://www.jarviscontracting.ca/guides/renovate-or-move)