There are many factors that impact the costs of building home additions in Toronto. To help break it all down clearly, Odima Construction has created this informational guide so homeowners can better grasp what exactly is involved in home addition costs such as permits, plans, fees, hiring professionals, etc., and the details of adding a second storey, a sunroom, and a home addition on a concrete slab. We’ll outline the benefits of each and the costs that will likely influence of the price of your next Toronto home addition project.

Average Home Addition Costs

The 7 main variables that influence the cost of a home addition are:

  • Architectural Complexity and Uniqueness
  • Ceiling Height
  • Finishes
  • Location
  • Property Access
  • Type of Existing Home Construction
  • Type of Home Addition
Types of Home AdditionsAverage Costs (incl. material & labour) in Toronto
Carport$90 to $120/sq. ft.
Four-season Sunroom on Piles (Unfinished)$360 to $420/sq. ft.
Four-season Sunroom on Piles (Turnkey)$312 to $432/sq. ft.
Garage Addition (Unfinished)$240 to $282/sq. ft.
Garage Addition (Turnkey)$288 to $360/sq. ft.
Home Addition on Piles (Unfinished)$312 to $360/sq. ft.
Home Addition on Piles (Turnkey)$360 to $420/sq. ft.
Home Addition on Foundation / Slab (Unfinished)$378 to $432/sq. ft.
Home Addition on Foundation / Slab (Turnkey)$432 to $480/sq. ft.
Storey Addition (unfinished)$312 to $390/sq. ft.
Storey Addition (Turnkey)$360 to $432/sq. ft.

Permits and Plans

Before building any home addition, you’ll need to obtain the necessary permits that comply with your city’s rules and regulations. By doing your due diligence, you will determine what kind of addition is allowed, what dimensions are accepted, whether siding options are permitted, and more. These planning rules have been put in place to specifically regulate home additions. In fact, many municipalities require you to get your plans done and have an authorized architect or technologist sign them before they will even hand over a permit.

The cost of a permit can vary depending on where you live and the type of home addition you intend on building. The average permit costs $240 and in regard to plans, depending on their complexity and if they’re done by a technologist, the cost can range anywhere from $2,400 to $4,200. Moreover, the plans are likely to cost you anywhere between 10% and 20% of your project’s total value if your project requires an architect’s expertise. Fortunately,

It’s fairly easy to find permit request information online for most cities, such as TorontoPickering, Markham, Mississauga, Vaughan, and Montreal. We suggest contacting your local planning department for further information.

Cost of Adding a Second Storey

A second storey addition not only expands your living space, but it also increases your property’s resale value significantly. For these reasons, it’s one of the most desirable home addition options sought after by homeowners in Toronto and across the GTA. A turnkey second storey addition is estimated to cost any figure between $300 and $360 per square foot. For example, a 1,000 sq ft addition costs in Ontario anywhere between $300,000 and $360,000.

You can also expect to allocate 2-3 months of time for planning, followed by another 3 or so months for construction, depending on the complexity of the project. Furthermore, you will want to check your city’s rules and regulations to ensure all permits are up to speed and try to minimize any potential roadblocks that may present themselves along the way.

Cost of Home Addition on a Concrete Slab

Another great option to extend your home’s living space is to build a home addition on a concrete slab. It’s more practical if you are not looking to excavate because your expansion will essentially be built on concrete that has been poured only once, otherwise known as monolithic concrete. This serves as both the foundation and floor of the new space.

Moreover, insulating a home addition built on a concrete slab is much easier and more effective than if you were to insulate a floor addition built on piles because the concrete slab retains heat during winter months. You will need to check if your property can withstand this kind of structure however, so if you do plan on going with this kind of addition, please verify in advance. If your property is durable enough and you are ready to expand, expect this Toronto house addition cost to be anywhere between $300 and $420 per square foot.

Cost of a Sunroom Addition

There are several options for building a sunroom. This home addition can be constructed on a foundation, piles, or a concrete slab. Most commonly, Toronto homeowners choose to get a four-season sunroom on piles because it is less expensive than other options. This type of home addition can run you anywhere between $250 and $380 per square foot. Similar to any other sort of home addition or the rest of the house, a sunroom addition needs to be ventilated, insulated, and heated. Conversely, a solarium or a three-season sunroom does not require the same approach because it is not necessarily considered to be a home addition.

A little tip: if your sunroom addition is going to face southward, consider installing slightly tinted windows. This addition is to prevent the space’s internal temperature from rising too high in the warmer months. The summertime also will likely require you to get air conditioning for this new space.


As a homeowner, your decision to extend your living space by building a home addition much in large comes down to the specific needs of you, your family, and the house. When embarking on your journey to decide whether to renovate or not, remember the 7 factors that influence costs, the average cost of adding a second story, a home addition on a concrete slab, and a sunroom addition, and refer to our helpful chart above which outlines the common types of home additions and their average costs per square foot in Toronto.

Traditionally, it will be less costly, less time-consuming, and less stress-inducing to add on, rather than build a home from scratch or move altogether, however, only your specific circumstances will dictate the best-suited option for you. Thorough planning and budgeting are vital for a successful home addition project.

Whether you have decided already that you are ready to start to plan for a home addition, or you have more questions and want to speak with our seasoned contractors, contact Odima Construction’s expert team right away!