Crew framing a second-storey addition on top of a brick bungalow on a tree-lined Toronto street

See What a Second Storey Costs Before You Build Up

Adding a 1,000 sq ft second floor with 3 bedrooms and 1 bathroom to a Toronto bungalow costs about $402,000 to $583,440 CAD before HST at 2026 prices. The low end places the new stairs over the existing stairs, and the high end adds a second bathroom, puts the stairs in a new spot, upgrades the finishes, and keeps your family living at home during the work.

A second storey adds living space and keeps your yard. The existing foundation and walls carry the new floor, so they get checked before the design is set.

Prices updated October 2026

Price Your Second Storey

New Floor

sq ft
Enter the floor area of the new storey in square feet.

Enter how many bedrooms the new floor has.

Enter how many bathrooms the new floor has.

New StairsSelect where the stairs to the new floor go.

House and Roof

Roof RemovalSelect whether the full roof or part of it comes off.
Existing HouseSelect how many storeys the house has today.
During the WorkSelect whether you move out or live in the home while the work happens.
Finish LevelSelect the quality level of the flooring, windows, trim, and fixtures.

Upgrades

Tick when the foundation or main-floor walls need strengthening to carry the new floor.
Tick to add a furnace or heat pump for the new floor.
Tick to replace the electrical panel with a larger one.
Tick to have True Frame Builders prepare the drawings and apply for the building permit.

Location

Enter the first 3 characters of your postal code to apply location-based pricing.

Fill in the fields above to see your price
Pick a time for True Frame Builders to visit, measure, and prepare your quote.Book a home visit

What Changes the Cost

  • Foundation and framing: An engineer checks the existing foundation and walls, and weak ones get reinforced.
  • Roof removal and protection: The old roof comes off, the house stays covered from weather, and a new roof goes on.
  • Stairs and the floor below: New stairs take space from the main floor and need patching around them.
  • Temporary support: Shoring holds the house while the structure changes.
  • Plumbing, heating, and electrical: The new floor needs its own lines, ducts, and circuits, and often a bigger panel.
Crew installing a steel beam and posts in the basement of a Toronto bungalow to carry a second-storey addition
A steel beam and posts strengthen the main floor so it carries the new storey.
Toronto bungalow with its roof removed and the open top covered in tarps during a second-storey addition
Tarps keep rain out of the house between roof removal and the new roof.
Carpenter framing a new staircase from the main floor up to a second-storey addition in a Toronto house
New stairs take space from the main floor, and the walls around them get patched and painted.

What Your Estimate Includes

Your estimate covers roof removal, weather protection, framing, the new roof, stairs, windows, insulation, interior finishes, and the bedrooms and bathrooms you count. Reinforcement, separate heating, and drawings are in the price when you tick them.

Before

One-storey brick bungalow on a Toronto street before a second-storey addition
The original one-storey bungalow and its front yard.

After

The same Toronto bungalow with a finished second storey, new roof, and new upstairs windows
A full second floor adds bedrooms and a bathroom, and the yard stays the same size.

What True Frame Builders Checks Before Your Quote

Engineer and contractor checking a Toronto bungalow foundation wall with the homeowners before a second-storey addition
True Frame Builders checks your foundation and walls with you before sending your quote.

Whether your foundation and walls carry a new floor depends on drawings, an engineer's review, and a site visit. True Frame Builders confirms the structure before the design is final. Your final price depends on site conditions, measurements, chosen materials, and the full work plan. True Frame Builders visits, measures, and then sends your quote.

Common Questions

How much does a second-storey addition cost in Toronto?

Adding a 1,000 sq ft second floor with 3 bedrooms and 1 bathroom to a Toronto bungalow costs about $402,000 to $583,440 CAD before HST at 2026 prices. The low end places the new stairs over the existing stairs, and the high end adds a second bathroom, puts the stairs in a new spot, upgrades the finishes, and keeps your family living at home during the work. Your own cost depends on your answers in the estimate and the condition of your home.

Can every house support a second storey?

Many houses can, once the foundation, walls, and roof are checked. Some need reinforcement first, and the zoning rules for your lot set the height you can build.

Do we need to move out during a second-storey addition?

Many families move out while the roof is off and the structure changes. Living at home adds protection and extra phases, and the estimate shows the difference when you switch between the two choices.

Plan the Next Part of Your Project

Many second-storey projects also include a home addition, load-bearing wall removal, or a whole-home renovation of the main floor. Each one has its own estimate, and your saved estimates add up to one project total.

For City of Toronto permit rules, see the Toronto guide to residential additions.