Home additions in the GTA

What a home addition involves

An addition is new construction attached to an existing house. It has everything a new build has: excavation and foundation, or a reinforced structure below; framing; roofing; windows and cladding; insulation; plumbing, electrical, and heating; and interior finishes. On top of that, it has to join an older building so that floors line up, the roof sheds water properly, and the result looks as if it was always there.

Common forms in the GTA:

• Rear addition. A larger kitchen, a family room, or a main-floor bedroom extending into the backyard.
• Side addition. Where the lot is wide enough, often a garage with rooms above, or a mudroom and office.
• Second-storey addition. A full upper floor on a bungalow, or rooms over an existing garage.
• Bump-out. A small extension of a metre or two that makes a tight kitchen or bathroom work.

Who it’s for

Homeowners who like where they live and need more house. The lot, the street, and the schools are right, and the cost of moving, with land transfer tax, fees, and a higher purchase price, makes staying and building the better choice. Bungalow owners on good lots are a typical case.

Signs an addition is the right answer

• You have already made the best of the existing floor area, and it is still not enough.
• The room you need has to be on a specific floor: a main-floor bedroom, or a kitchen that can seat the family.
• A basement renovation would add space, but not the kind you need.
• Your lot has room within the zoning setbacks, or the house can carry another storey.

If the need can be met by reworking the space you have, a full home renovation costs less than adding to it. We will say so if that is what we see.

Zoning comes first

Before design goes far, we check what your lot allows. Every municipality’s zoning by-law limits how close you can build to the property lines, how tall the house can be, and how much of the lot it can cover. Properties near ravines, creeks, or the lake may also need approval from the local conservation authority, and homes in heritage districts have their own review.

If the addition you want does not fit the by-law, a minor variance can be requested through the municipality’s Committee of Adjustment. That is a public process with its own timeline, so it is better to know at the start.

Our process

1. Phone conversation. What space do you need, and what would you like to spend?
2. Free site visit. We look at the house, the lot, and access for equipment.
3. Zoning check, budget, and design. We confirm what can be built, agree on a realistic budget, and design from your inspiration photos.
4. 3D rendering. On request, a full rendering shows the addition from the street, from the yard, and from inside.
5. Engineering and permits. Structural design, permit drawings, and the application.
6. Build. Foundation or structural work, framing, closing in, then the connection to the existing house and interior finishing.

Where the addition includes a new kitchen, the existing kitchen stays in service for as long as possible, on the same principle we apply to every kitchen renovation. Read more on our process page.

Timelines

An addition is the longest type of residential project. Industry-wide, design, engineering, and permit review typically take a few months, and construction another four to eight depending on size and season. Foundations are best poured outside the coldest months.

TODO: owner to confirm Calico's typical timelines for additions.

Permits

A building permit is always required. See our guide to renovation permits in Ontario for how the process works, and our guide on choosing a renovation contractor for what to ask anyone you are considering for a project of this size.