Just Completed: Three-Storey Rear Addition on Sheridan Avenue, Toronto
Updated: 3 days ago
We’re pleased to share the completion of this three-storey rear addition on Sheridan Avenue in Toronto. This project is a great example of how an existing home on a narrow urban lot can be significantly expanded while working within challenging site and construction constraints.
The goal was to create substantially more usable living space for the homeowners without losing the advantages of their existing Toronto property. Rather than starting over, the project focused on transforming the rear of the house with a new three-storey addition designed around the existing building, available lot area and zoning requirements.
Now that construction is complete, the difference between the original house and the finished addition is dramatic.
The Existing Home
Before construction, the rear of the house had a relatively small footprint and limited connection to the backyard. Like many older Toronto properties, the house sits on a narrow lot with very little space between neighbouring homes.
This presented an important challenge from the beginning. The design needed to maximize the available space while considering the existing structure, neighbouring properties, zoning requirements and practical construction access.
The existing conditions were documented before design work began, allowing the proposed addition to be developed around the actual dimensions and constraints of the property.
Designing a Three-Storey Rear Addition
The new addition extends the home vertically across three storeys, creating additional living space on multiple levels while maintaining a relatively compact footprint.
Careful space planning was particularly important. On a narrow Toronto property, every part of the available building area needs to work efficiently. The addition was designed to improve the interior layout while creating a much stronger connection between the new spaces and the rest of the house.
The exterior was given a distinctly contemporary appearance. Large windows bring natural light into the new interior spaces, while a combination of vertical and horizontal siding helps emphasize the height and proportions of the addition.
The result is intentionally modern while still remaining connected to the scale of the surrounding residential neighbourhood.
A Challenging Construction Site
One of the most interesting aspects of this project was not simply the size of the addition, but how it had to be built.
Construction access was extremely limited.
The narrow spacing between neighbouring houses meant that conventional access from the front or sides of the property was difficult. Much of the builder’s access therefore had to be coordinated through the rear laneway.
For a three-storey addition, this creates additional logistical challenges. Lumber, structural components, equipment and other construction materials all need to reach the rear of the property, while the available staging area is very limited.
The construction photos show just how constrained the working area was as the new wood framing began rising behind the existing house.
Working within these conditions required careful coordination between the design, structural requirements and the realities of construction on a tight urban site.
Architectural and Structural Coordination
A project of this scale requires the architectural and structural design to work together from the beginning.
Cadaxx Design prepared the architectural design and permit drawings and coordinated the required structural engineering for the addition.
The new structure needed to integrate with the existing home while supporting three levels of additional construction. Openings, floor systems, roof conditions and connections between the existing and proposed portions of the house all had to be considered as part of the design process.
The drawings were developed not only for building permit approval, but also to provide the information required to translate the design into construction.
From Framing to Finished Home
As construction progressed, the overall form of the addition began to take shape.
What initially appeared as a tall wood-framed structure at the rear of the property gradually became the finished contemporary addition shown today.
The completed rear elevation features large windows across all three levels, bringing considerably more natural light into the home. The modern cladding and simple architectural detailing give the addition a clean appearance, while the vertical proportions make effective use of the narrow property.
Comparing the existing house, construction framing and completed project provides a clear picture of the transformation.
Making Better Use of a Toronto Property
Projects like Sheridan Avenue demonstrate why additions can be an attractive option for homeowners who need more space but want to remain in their existing neighbourhood.
Toronto lots are often constrained by width, neighbouring buildings and limited construction access. These conditions do not necessarily prevent a substantial addition, but they make early planning particularly important.
Zoning, building height, setbacks, lot coverage, existing conditions, structural requirements and construction feasibility all need to be considered when developing the design.
For this property, building vertically allowed a significant amount of new living space to be created without requiring an unusually large rear footprint.
A Dramatic Before-and-After Transformation
The strongest way to understand this project is to compare the photographs.
The original rear of the house was modest and traditional. During construction, the three-storey wood structure shows the scale of the new addition and the challenge of building within such a narrow space. The completed photograph reveals an entirely transformed home with a contemporary rear elevation and substantially more usable interior space.
It is especially rewarding to see a project move all the way from existing conditions, through design and permitting, into construction and finally completion.
The Sheridan Avenue project is now fully constructed and stands as an example of what can be achieved with thoughtful design on a challenging Toronto lot.
Project: Sheridan Avenue, Toronto
Project Type: Three-Storey Rear Addition
Scope: Architectural Design, Permit Drawings & Structural Coordination
Construction Access: Narrow Lot / Rear Laneway
Status: Completed 2026
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