Durham Region
Home additions in Durham Region
Home additions across Durham Region, Ontario: why they pay no development charges, and how permit fees, lot coverage and variance costs vary by town.
Does a home addition pay development charges anywhere in Durham Region?
No. An addition that enlarges your house without creating a new home pays no development charges in any Durham Region town, under the Development Charges Act, Durham's By-law 42-2023 and the Durham District School Board's by-law, as of October 2026. A new house pays $76,227 to the Region alone. An addition pays the town's permit fee instead, such as $22.37 per m² in Whitby or $15.56 per m² in Oshawa.
Key takeaways
- An addition that only enlarges an existing home is exempt from development charges (Development Charges Act, s. 2(3)), while a new serviced house pays Durham Region $76,227 (Durham Region, 1 July 2026).
- Maximum lot coverage in the common detached zones runs from 20% in Whitby's older R1 to R3 zones to 45% in Ajax's R1-C to R1-F zones (Town of Whitby By-law 1784, Town of Ajax Section 6).
- Since 21 November 2025, minimum setbacks on urban residential land are deemed 90% of the by-law figure, so a 7.5 m rear yard becomes 6.75 m (O. Reg. 545/06).
- CLOCA charges $930 to review a minor variance in its regulated area, and TRCA $695 to $1,000 for a residential one, on top of the town's fee (CLOCA 2026 fees, TRCA 2026 fees).
- Permits for renovations, additions and improvements across Durham were worth $119.6 million in 2025, down from $133.7 million in 2024 (Durham Region 2025 Annual Building Activity Review).
Permits in Durham Region
What applies to home additions here, with the municipal source for each line.
| Item | What applies | Source |
|---|---|---|
| Ajax: addition permit fee | $14.22 times the floor area; the Ajax schedule doesn't say whether the area is measured in m² or sq ft | ajax.caChecked 5 October 2026In the source's wordsSection A: CONSTRUCTION of new buildings, additions to existing buildings, including mezzanines |
| Brock: addition permit fee | $19.90 per m² | media-002-ca.cdn.govstack.comChecked 5 October 2026In the source's wordsNew or Additions - SFD, Semi Link, Towns $19.90 |
| Clarington: addition permit fee | $17.73 per m² | weblink.clarington.netChecked 5 October 2026In the source's wordsSingle Family Dwellings, Semis, Townhouses, Duplexes, Live/Work Units $17.73 per sq.m |
| Oshawa: addition permit fee | $15.56 per m² | media-002-ca.cdn.govstack.comChecked 5 October 2026In the source's wordsHouse, Accessory building for human habitation $15.56 / sq. m. |
| Pickering: addition permit fee | No separate addition line in the July 2026 fees; the Chief Building Official sets the building category and floor area (Building By-law 8057/23 s.15(3)). Residential buildings are $20.12 per m² of gross floor area | corporate.pickering.caChecked 6 October 2026In the source's wordsthe Chief Building Official, or a person designated by the Chief Building Official, shall determine the appropriate building category, floor area and/or value, and that determination shall be final. |
| Scugog: addition permit fee | $20.43 per m² | media-001-ca.cdn.govstack.comChecked 5 October 2026In the source's wordsNew Construction and Additions (for each m2 of GFA or part thereof) ... Other Residential Buildings $20.43 |
| Whitby: addition permit fee | $22.37 per m² | media-003-ca.cdn.govstack.comChecked 5 October 2026In the source's wordsResidential (SFD, Semi, Townhouse, Link, Duplex & Live/Work) - New / Additions Per m2 No $22.37 |
| Ajax: conservation authority (1) | Toronto and Region Conservation Authority (TRCA) | ajax.caChecked 5 October 2026In the source's wordsYour property might be in a regulated area; please reach out to Town Planning staff, the Toronto and Region Conservation Authority (TRCA), or the Central Lake Ontario Conservation Authority |
| Ajax: conservation authority (2) | Central Lake Ontario Conservation Authority (CLOCA) | cloca.comChecked 5 October 2026In the source's wordsSheet 1 - Lakeshore Ajax - Halls Road South, Whitby |
| Brock: conservation authority (1) | Lake Simcoe Region Conservation Authority (LSRCA) | lsrca.on.caChecked 5 October 2026In the source's wordsTownship of Brock - Memorandum of Understanding |
| Brock: conservation authority (2) | Kawartha Conservation | kawarthaconservation.comChecked 5 October 2026In the source's wordsOur municipal partners include: City of Kawartha Lakes, Township of Scugog, Township of Brock |
| Clarington: conservation authority (1) | Central Lake Ontario Conservation Authority (CLOCA) | cloca.comChecked 5 October 2026In the source's wordsOur municipal partners include the Region of Durham, Cities of Oshawa and Pickering, Towns of Ajax and Whitby, Municipality of Clarington and Townships of Scugog and Uxbridge. |
| Clarington: conservation authority (2) | Ganaraska Region Conservation Authority (GRCA) | grca.on.caChecked 5 October 2026In the source's wordsfrom Wilmot Creek in Clarington to east of Cobourg ... This area includes seven municipalities in whole or in part ... Municipality of Clarington |
| Clarington: conservation authority (3) | Kawartha Conservation | kawarthaconservation.comChecked 5 October 2026In the source's wordsOur municipal partners include: City of Kawartha Lakes, Township of Scugog, Township of Brock, Municipality of Clarington |
| Oshawa: conservation authority | Central Lake Ontario Conservation Authority (CLOCA) | oshawa.caChecked 5 October 2026In the source's wordscontact the Central Lake Ontario Conservation Authority (C.L.O.C.A.) |
| Pickering: conservation authority (1) | Toronto and Region Conservation Authority (TRCA) | pickering.caChecked 5 October 2026In the source's wordsToronto Region Conservation Authority |
| Pickering: conservation authority (2) | Central Lake Ontario Conservation Authority (CLOCA) | pickering.caChecked 5 October 2026In the source's wordsCentral Lakes Ontario Conservation Authority |
| Scugog: conservation authority (1) | Kawartha Conservation (most of Scugog) | scugog.caChecked 5 October 2026In the source's wordsThe Township of Scugog has three (3) Conservation Authorities, being Kawartha Conservation, Lake Simcoe Region Conservation Authority, and Central Lake Ontario Conservation Authority. |
| Scugog: conservation authority (2) | Lake Simcoe Region Conservation Authority (LSRCA) | lsrca.on.caChecked 5 October 2026In the source's wordsCouncillor Durham Region (Scugog) |
| Scugog: conservation authority (3) | Central Lake Ontario Conservation Authority (CLOCA) | cloca.comChecked 5 October 2026In the source's wordsOur municipal partners include ... Municipality of Clarington and Townships of Scugog and Uxbridge. |
| Whitby: conservation authority | Central Lake Ontario Conservation Authority (CLOCA) | whitby.caChecked 5 October 2026In the source's wordsCentral Lake Ontario Conservation Authority |
| Durham Region development charges, regional (as of 2026-07-01) | $76,227 | media-003-ca.cdn.govstack.comChecked 5 October 2026In the source's wordsTotal of All Charges $76,227 |
| Durham Region development charges, education (as of 2026-07-01) | $7,535 | media-002-ca.cdn.govstack.comChecked 5 October 2026In the source's wordsResidential (per dwelling unit) $4,349 $3,186 $7,535 |
Fees and rules as published by each municipality in Durham Region and the agencies linked, checked 6 October 2026. Confirm with the building department before you apply.
The nearest finished jobs
West Lynde
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.
Explore the home
Greenwood
Top floor replaced with a new storey, rear extension, basement enlarged, full interior design and build.
Explore the home
What it costs
Ranges with their sources, not quotes.
| Work | Range | Basis | Source |
|---|---|---|---|
| Home addition, any type | $350 to $600per sq ft | GTA, 2026. Before 13% HST. | Our 2026 price |
| Single-storey rear addition, 300 to 700 sq ft | $180,000 to $450,000 | GTA, 2026. Before 13% HST. | Our 2026 price |
| Bump-out, 100 to 300 sq ft | $60,000 to $180,000 | GTA, 2026. Before 13% HST. | Our 2026 price |
Our 2026 ranges, not quotes: every job is priced after a site visit.
What moves the number
- The foundation: full basement, crawlspace or slab
- How much of the existing house opens up to join the new space
- The roof: new rafters meeting the old roof
- Engineering, drawings and the permit
- Finish level inside
- 13% HST, which these ranges leave out
Building in Durham Region
How do Durham Region's towns compare for an addition?
Three exemptions line up for an addition. The Act's section 2(3), section 2.12(b) of Durham's By-law 42-2023 and section 10(2)(i) of the public school board's by-law all leave the enlargement of an existing home alone. So the costs that differ are local. As of October 2026:
| Town | Addition permit fee | Fee on a 40 m² addition (our arithmetic) | Max lot coverage, common detached zone | Residential minor variance |
|---|---|---|---|---|
| Whitby | $22.37 per m² | $894.80 | 20% (R1 to R3, By-law 1784; newer zones differ) | $1,526 |
| Scugog | $20.43 per m² | $817.20 | 45% (urban residential) | $2,760 |
| Brock | $19.90 per m² | $796.00 | 40% (R1 to R3) | $1,530 (year not stated) |
| Clarington | $17.73 per m² (Group C rate; confirm with the Building Division) | $709.20 | 40% (R1); 25% to 35% in Bowmanville's overlay | $2,280 |
| Oshawa | $15.56 per m² | $622.40 | 40% (R1-A to R1-E) | $856 (year not stated) |
| Ajax | $14.22 times the floor area (the schedule doesn't print the unit) | Not calculated | 45% (R1-C to R1-F); 30% R1-A, 33% R1-B | $1,638.90 (2025 rate) |
| Pickering | No addition line in the 2026 schedule | Not calculated | 33% (R1C to R1E); 38% (R1F to R1I) | $2,500 (from 1 July 2026) |
| Uxbridge | Not verified (undated schedule) | Not calculated | 30% (R1) | $877 |
Note: fees from each municipality's current schedule and coverage from its zoning by-law's usual detached zone; your lot's zone may carry its own numbers, and minimum permit fees can apply to small jobs.
Coverage is where an addition hits the wall. A 600 m² lot in one of Whitby's older R1 zones can hold 120 m² of building, while the same lot in Ajax's R1-C zone could hold 270 m² (our arithmetic). When you need more, the variance bill swings too: Scugog's $2,760 is more than three times Oshawa's $856, and a Pickering lot in TRCA's regulated area could pay $2,500 plus $695, or $3,195 (our arithmetic).
The 90% setback relief has holes that matter here. The relief stops at the Greenbelt and at prescribed areas near shorelines, wetlands, valleys and railways, and Durham has its share of those, from the Lake Ontario shoreline to creek valleys such as Duffins Creek. Lots near them still need the full by-law setback or a variance.
Our nearest finished addition is West Lynde in Whitby, a bungalow taken up to two storeys. The nearest rear extension is Greenwood in Toronto, with a new top storey, roughly 27 km west of central Pickering. Its foundation got new waterproofing and weeping tile while the walls were open.
How the job runs in Durham Region
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.
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.
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.
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.
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.
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.
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. Each municipality in Durham Region takes its own applications; the table above names where.
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.
Inspections
The municipal building inspector checks the work at each stage the permit sets, before it gets covered up. Inspections are booked with the local building department.
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 warranty1 year workmanship and materials, 2 years plumbing, heating, electrical and building envelope, 7 years structural
- BBB Accredited BusinessAccredited by the Better Business Bureau since November 2025
- Durham Region Home Builders' AssociationMember, Renovators
- RenoMarkRenoMark renovator, through the DRHBA
Questions
Which Durham Region town allows the most lot coverage for an addition?
Does Ontario's 90% setback rule apply in every Durham Region town?
What does a conservation authority add to a minor variance in Durham Region?
Does an addition with its own kitchen pay development charges in Durham Region?
How much did Durham Region spend on renovations and additions in 2025?
Sources
- Development Charges Act, 1997 ontario.ca
- Durham Region, By-law 42-2023 (regional development charges) durham.ca
- Durham Region, development charges from 1 July 2026 media-003-ca.cdn.govstack.com
- Durham District School Board, 2024 education development charge by-law media-003-ca.cdn.govstack.com
- Durham Region, 2025 Annual Building Activity Review media-003-ca.cdn.govstack.com
- O. Reg. 545/06 (setbacks deemed 90%) ontario.ca
- CLOCA 2026 fee schedule cloca.com
- TRCA development planning fees, 1 February 2026 trcaca.s3.ca-central-1.amazonaws.com
- Town of Whitby, 2026 building permit fees media-003-ca.cdn.govstack.com
- City of Oshawa, Building By-law 33-2009 fees media-002-ca.cdn.govstack.com
- Town of Ajax: Building By law 48 2023 Sch A Jan 01 2026 ajax.ca
- Township of Brock: Schedule a 2026 fees web media-002-ca.cdn.govstack.com
- Municipality of Clarington: ElectronicFile weblink.clarington.net
- City of Pickering: DocView corporate.pickering.ca
- Township of Scugog: Required building fees 2026 media-001-ca.cdn.govstack.com
- Town of Ajax: Committee of adjustment ajax.ca
- CLOCA: Regulation area mapping cloca.com
- LSRCA: Governance lsrca.on.ca
- Kawartha Conservation: About us kawarthaconservation.com
- CLOCA: About us cloca.com
- grca.on.ca grca.on.ca
- City of Oshawa: Building permits oshawa.ca
- City of Pickering: Building permits pickering.ca
- Township of Scugog: Additional dwelling units scugog.ca
- Town of Whitby: Building permits whitby.ca
- City of Pickering: Developmentcharges citywide 2026 media-002-ca.cdn.govstack.com
How this page was made
Written by Jarvis Contracting from the municipalities' published rules, our 2026 price ranges and the nearest finished jobs.
- Facts checked
- 6 October 2026
- Fact-checked
- Space & Story, 5 October 2026