How much does home additions cost in Toronto?

With Zigma Group, home additions starts from $315 per sq ft. Prices are in Canadian dollars before HST, as of October 2026, and are confirmed after a site visit. The main factors are size and number of storeys; foundation type and site access; and kitchens or bathrooms inside the addition.

How do I know if I can build an addition on my lot?

It depends on your zoning: setbacks from the lot lines, maximum height, lot coverage and floor area. We review these for your address at the start and tell you what fits as of right and what would need a variance.

What is a minor variance?

It is permission from your municipality's Committee of Adjustment to build slightly outside a zoning rule, such as a reduced setback. It involves an application and a public hearing, and it happens before the building permit.

Do you do home additions projects in Toronto?

Yes. We work throughout Toronto, including Leaside, The Annex, High Park, Riverdale, The Beaches, Forest Hill and Lawrence Park. Call +1 (647) 718-3913 to arrange a visit.

Who issues the permit for this work in Toronto?

Where a permit is needed, it is issued by the City of Toronto (Toronto Building). We prepare the drawings and handle the application and inspections.

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Home Additions

More space · Toronto

Home Additions in Toronto

An addition gives you the space you need without leaving the street you like. We design it to look like it was always part of the house and tie it properly into the existing structure. In Toronto, much of the housing is pre-war: narrow semis and detached brick houses with plaster walls, old wiring and shared party walls.

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New brick walls and window openings of a house under construction — From our Damavand project

Scope

What is included.

Zoning review of setbacks, height and lot coverage
Architectural and structural drawings
Building permit and, where needed, minor variance applications
Foundations, framing and roofing
Matching brick, siding and windows
Opening and finishing the connection to the existing house

Cost

What it costs.

From $315per sq ft

What moves the price

Size and number of storeys
Foundation type and site access
Kitchens or bathrooms inside the addition

Prices are in Canadian dollars before HST, as of October 2026. Every project is confirmed with a written quote after a site visit.

Local knowledge

Home Additions in Toronto.

Homes like these
On narrow older lots, additions usually go to the rear or upward, and often need a minor variance.
Housing
In Toronto, much of the housing is pre-war: narrow semis and detached brick houses with plaster walls, old wiring and shared party walls.
Permits
Building permits in Toronto are issued by the City of Toronto (Toronto Building). We prepare the drawings, submit the application and book the inspections.
Areas we cover
We work throughout Toronto, including Leaside, The Annex, High Park, Riverdale, The Beaches, Forest Hill and Lawrence Park.
Suites and multiplexes
Toronto permits laneway suites, garden suites and, on most residential lots, up to four units in a house. That makes basement apartments and rear additions more feasible here than in many suburbs.
Tight lots
Narrow lots and shared walls mean additions and underpinning often need a minor variance or a neighbour's cooperation, so the approvals take planning.

Before you start

What to know.

Zoning comes first
Every lot has limits on how far, how high and how much of it you can build on. We check those before design begins. If the addition goes beyond them, a minor variance from the Committee of Adjustment is needed.
Permits
All additions need a building permit, with drawings showing structure, insulation and how the new part connects to the old.
Joining old and new
The connection is the hard part: matching floor levels, carrying the loads of the opened wall, and extending heating and plumbing.

How we work

One team for every stage.

AssessWe survey the house as it stands.
Design and permitsDrawings and approvals before work starts.
Strip-outWhat is worn out comes off.
RebuildStructure, wiring, plumbing and walls.
FinishesCabinetry, tile, floors and paint.
HandoverWalkthrough and documents.

Questions

Home Additions in Toronto: the short answers.

How much does home additions cost in Toronto?: With Zigma Group, home additions starts from $315 per sq ft. Prices are in Canadian dollars before HST, as of October 2026, and are confirmed after a site visit. The main factors are size and number of storeys; foundation type and site access; and kitchens or bathrooms inside the addition.
How do I know if I can build an addition on my lot?: It depends on your zoning: setbacks from the lot lines, maximum height, lot coverage and floor area. We review these for your address at the start and tell you what fits as of right and what would need a variance.
What is a minor variance?: It is permission from your municipality's Committee of Adjustment to build slightly outside a zoning rule, such as a reduced setback. It involves an application and a public hearing, and it happens before the building permit.
Do you do home additions projects in Toronto?: Yes. We work throughout Toronto, including Leaside, The Annex, High Park, Riverdale, The Beaches, Forest Hill and Lawrence Park. Call +1 (647) 718-3913 to arrange a visit.
Who issues the permit for this work in Toronto?: Where a permit is needed, it is issued by the City of Toronto (Toronto Building). We prepare the drawings and handle the application and inspections.