How to Add a Second Story to a Toronto Bungalow

Adding a second story to a Toronto bungalow is a three-part process: confirm zoning and structure, design and permit the new floor, then build and tie the new level into your existing services and exterior. In Toronto, second-storey additions usually range from $250,000–$550,000+ depending on size, structure, and finish level, which makes working with an experienced design–build team essential for realistic budgeting, smooth permitting, and efficient construction.

Why Homeowners Add a Second Story in Toronto

Bungalows across Toronto often have strong bones and great lots, but limited square footage. A second-storey addition almost always doubles the usable space while preserving the yard and boosting long-term property value. When designed well, the new level allows for a modern layout upstairs and meaningful improvements to the main floor, transforming an older bungalow into a spacious, functional family home.

Step 1: Feasibility, Zoning, and Budget

Before drawings or design ideas begin, the first step is confirming whether your bungalow can structurally and legally support another level. This early phase determines what’s possible and prevents costly surprises later.

Zoning and Municipal Rules

Toronto’s zoning bylaws dictate maximum allowable height, floor space index, and how closely you can build to your property lines. Most bungalow top-ups fit within as-of-right permissions, but if your preferred design exceeds local limits, you may need approval from the Committee of Adjustment. That process commonly adds eight to twelve weeks and requires a minor variance application, drawings, and sometimes neighbour consultation. It’s not unusual for top-ups, but it’s something homeowners must account for in their overall timeline.

Structural Assessment

A structural review ensures the existing foundation and main-floor framing can support a new level. Many older bungalows require reinforcing beams, upgraded load paths, or new posts in the basement to safely handle the added weight. 

Establishing a Budget Range

Once zoning and structural feasibility are confirmed, budget discussions begin. Most second-storey additions on 800–1,200 sq. ft. bungalows fall in the $300,000–$400,000 range, but projects that include main-floor reconfiguration, high-end finishes, or major structural reinforcement can reach $500,000 or more. 

Establishing this range early helps homeowners make informed design decisions and understand what scale of addition best fits their budget.

Step 2: Design and Permits

With feasibility established, the next step is full architectural and structural design. This phase translates your needs-more bedrooms, a primary suite, extra bathrooms, a laundry room-into a functional second-floor layout that aligns with zoning, engineering, and the overall design of the existing bungalow.

Architectural Planning

A second-storey addition is an opportunity to rethink both the interior and the exterior of your home. Plas bedroom layouts, bathroom locations, a new staircase connection, and the general circulation of the new level. The design must also work beautifully with the exterior form of the bungalow. Rooflines are adjusted, windows are aligned for symmetry, and exterior materials are selected to blend the new level with the home below. This ensures your upgraded home looks intentional, cohesive, and attractive from the street, not like an add-on.

Structural Engineering

Every second-storey addition requires coordinated engineering. Floor systems, beams, posts, and shear walls must be sized appropriately, especially if the main floor is being reworked to create an open-concept layout. Engineering is also critical for HVAC design, since the new upper level must tie into or extend the existing system. Toronto General Contractors manages the engineering process so homeowners receive a complete, permit-ready package without juggling multiple consultants.

Permit Submissions

Once architectural and structural drawings are complete, the building permit submission can be made. If minor variances are needed, Toronto General Contractors prepares the Committee of Adjustment application, attends the hearing, and coordinates any revisions required by the City. Permit approval typically takes one and a half to three months, depending on whether variances are involved and how quickly city comments are resolved.

Selecting Materials and Finishes

While permits are underway, homeowners choose both exterior and interior finishes. Exterior materials-such as siding, stucco, or brick veneer-must be chosen to complement the existing bungalow. Inside, decisions are made for flooring, trim, paint, plumbing fixtures, lighting, and cabinetry. These choices influence both the design details and the final cost.

Step 3: Construction Sequence

Once permits are issued, construction begins. Building a new storey on an existing bungalow happens in a well-choreographed sequence, because timing is crucial-especially during roof removal and framing when the home is temporarily exposed.

Site Preparation and Roof Removal

Before any demolition happens, the contractor protects the interior, secures the site, and takes precautions for neighbours and landscaping. The existing roof is then removed so the new floor structure can be installed. This part is carefully scheduled to minimize the time the interior is open to weather.

Framing the New Level

Carpenters begin by installing the new floor joists and framing the exterior and interior walls. Openings for windows and doors are cut, and the new staircase linking the main level to the second floor is framed. A new roof structure is then built, shaping the upper level into a complete architectural form.

Creating the Building Envelope

Once the shell is framed, the house must be sealed as quickly as possible. Sheathing goes on, roofing materials are installed, and new windows and doors are fitted. Exterior cladding is added, and tie-ins to the original walls are completed so the entire home becomes weather-tight. Proper envelope work is essential to durability, energy efficiency, and long-term performance.

Mechanical Rough-Ins and Insulation

With the shell secured, the mechanical systems are extended or upgraded. HVAC is redistributed to serve the new level, plumbing lines are installed if bathrooms or laundry are included, and electrical circuits are run throughout. After rough-ins pass inspection, insulation is added to meet energy code requirements.

Interior Finishing

Drywall installation marks the transition into the finishing phase. Trim, paint, flooring, cabinetry, and fixtures follow in a sequence that moves the project toward occupancy. Toronto General Contractors manages inspections, schedules trades, and ensures every detail aligns with the approved plans and homeowner selections.

Timelines and Practical Expectations

A realistic timeline for a Toronto bungalow top-up is roughly one to three months for design, one and a half to three or more months for permits, and four to six months for construction. Weather, the need for variances, and the complexity of the main-floor reconfiguration all influence this schedule. Because roof removal and major renovation work can be disruptive, many homeowners choose to live elsewhere temporarily, especially during the early phases of construction.

Get a Custom Plan and Accurate Budget for Your Bungalow

A second-storey addition is one of the most effective ways to modernize a Toronto bungalow and dramatically increase living space. With typical costs ranging from $250,000–$550,000+, success depends on careful planning, thoughtful design, and a skilled construction team.

If you share your bungalow’s approximate square footage, neighbourhood, and target layout-such as “three bedrooms, two bathrooms, and laundry upstairs”- a more precise budget range and a sample scope of work that Toronto General Contractors can deliver can be outlined for you.

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