Key Summary

  • Benefits of home addition
  • Factors affecting home addition costs in Toronto
  • What you should know about obtaining permits
  • Home extension costs in Toronto
  • Sunroom addition cost
  • Cost to add a second story
  • Cost for a basement addition
  • Comparison of house addition costs based on construction method
  • Cost to convert an attic
  • Cost to add a room by size
  • FAQs

The 2024 Cost of Home Additions in Toronto: What You Should Know Before You Start

Home addition is a popular home improvement project many Toronto homeowners are embarking on, and for a good reason. Extending your home offers many benefits and may be a great idea for your home if you need more space.

One of the first questions people have about house extensions is: How much does an addition cost? Well, it depends. In this blog, we’ll discuss the various factors that affect house addition costs, the benefits of adding to your home, and what you can expect to pay based on the type of home addition.

Benefits of Home Addition

  • Increases your home’s square footage and value—A home addition is a worthwhile investment that gives you more room and boosts your home’s value.
  • Keep the home you love – You don’t have to sell your home because you need more space. Home addition allows you to keep the home and neighborhood you love and simply extend it.
  • Avoid the hassle of moving—Selling your home, buying a new one, and moving in is stressful. A great solution to the need for more space is extending and designing an additional room that accommodates your needs.

The Cost of Home Extension in Toronto

How much a home addition costs depends on a number of variables that are specific to the home and project. However, on average, a home addition typically ranges between $400 and $500 per square foot.

So, the size of the new room will greatly determine the cost of the project. One of the challenges with home additions is that you don’t always know how much it will cost until the details of the project are examined. A small addition may cost more than expected based on the terrain or other construction challenges that need to be rectified to build the addition.

Factors Affecting Home Addition Costs in Toronto

Being aware of the variables that will impact the cost of your home addition in Toronto will help you plan according and get a better idea of the project’s cost.

Some types of rooms require less labour and materials than others. For example, adding a kitchen will require plumbing and electrical updates, ventilation, cabinets, countertops, etc. Whereas a bedroom is less complex and does not have the same requirements.

Designs with a higher level of difficulty will cause the house addition costs to increase. So if you opt for a custom design instead of a standard design, you’ll definitely see a difference in the price.

Because your new addition will be an extension of your home, the type of construction and materials used for the structure will need to be consistent. Construction types and materials vary in cost.

The volume of the addition will affect the cost. Higher ceilings will result in higher costs.

Where you plan to add the new room will impact the cost. Generally, additions made to the first floor tend to be less than the cost of adding a second-story.

High-end finishes are expensive. If you choose to go with luxury finishes, then your home addition costs will add up significantly.

Your contractor will consider how difficult it is to access your property. Builders also factor in how far supplies and equipment need to be transported to the home. If you live in a remote area that is difficult to access, your costs will increase.

Permits and Plans

Before you can begin any construction work, you will need to determine what type of permits are required for the project and obtain them from your municipality. Zoning regulations establish rules and guidelines about what types of home extensions are permitted in the area. Make sure that you know these guidelines before proceeding with your home addition plan.

Before issuing a permit, most principalities will require plans that have been drawn up by a qualified architect. How much you will need to spend on the permits depends on where you live and the nature of the home addition. On average, the cost of permits is $240. However, having an architect or professional draw up your building plans can cost anywhere from $2,400 to $4,200. In general, the plans for your project will range from 10-20% of the total cost of your home addition.

Cost of Adding a Second Story

Adding a second story to your home is a good way to increase your home’s square footage without taking up additional land. Homeowners who don’t have the land capacity to expand their home horizontally can extend vertically.

Plus, two-story homes perform better on the market. So if you plan to sell your home at some point, having a second story works to your advantage. The cost of adding a second story in Toronto is between $300-$360 per square foot. So depending on the size, the cost will fluctuate.

Size of home additionAverage Cost
1000 ft.²$300,000 – $360,000
1200 ft.²  $360,000 – $432,000
1500 ft.²  $450,000 – $540,000
2000 ft.²$600,000 – $720,000

Some of the renovations with the best ROIs are:

Planning a second-story addition takes a few months. The structural integrity of the home will be critical in determining whether such an addition is feasible and safe. If there are no delays, a turnkey second-story addition can take about three months to complete. Be sure to acquire the necessary permits before beginning the process.

Sunroom Addition Cost

A sunroom is an excellent addition to your home. It allows you to enjoy some good Vitamin D without being exposed to weather elements. Your sunroom needs to be designed to allow for sufficient ventilation and insulation. Different construction methods are used to build sunrooms, and careful thought should go into determining which one is the best option for you. Your sunroom will either be built on a foundation, piles, or concrete slab.

Many homeowners in Toronto choose to have their sunrooms constructed on piles because it is the least costly of the three, costing between $250-$380 per square foot.

Comparison of House Addition Cost Based on Construction Method– Foundation vs Piles vs Concrete Slab

Construction TypeAverage CostProsCons
Piles$225-$270· Easier to build and uses less invasive machinery.
· High ROI
· Does not offer the best insulation, so energy bills will be high during winter.
Concrete Slab$265-$310· Offers better insulation· Temperature fluctuations and soil settling can cause cracks.
Foundation$265-$310· Good option if you are adding plenty of space.· Blending the addition takes great skill.

The Cost of Adding a Basement

There are many practical reasons why having a basement in your home is beneficial. However, it is a complicated and very costly venture. This is because the house will need to be lifted first, which costs around $40,000-$65,000, and foundational work to include the basement will be an additional $40,000-$60,000. This is in addition to the cost of finishing a basement which is about $50 per square foot. So, when all is said and done, you may spend anywhere from $150,000-$300,000.

If you already have a basement and would like to expand that space, you can do so through underpinning. The cost will vary, and it is important to note that this kind of home addition may not be suitable for every home. If the home is made of wood or some other light weighing material, then underpinning will be a lot easier to do. However, if the home has masonry covering its exterior, it will be a much more difficult and expensive process.

Cost to Convert an Attic

An attic is typically used for storage. Make this space more useful by converting it into a more functional room. The key with attic conversion is that your roof needs to be at least 7 feet above the floor of your attic for most of the surface area.

If this isn’t the case, then you’ll need to lift the roof. Doing this can cost between $30-$42 per square foot. You’ll need to hire a structural engineer to make sure that the conversion is possible and can be done safely without jeopardizing the rest of the home.

Cost to Add a Room by Room Size

Room SizeAverage Cost
10×10 room addition$12,500-$25,000
12×12 room addition$18,000-$36,000
20×20 room addition$50,000-$100,000


The best addition for your house depends on a variety of factors, including the purpose of the new room, your goal, budget, property size, and zoning laws.

Yes. Anytime you increase the square footage of your home and add more functional space to the home, you will increase the value of the property.

Adding a 12×12 room to a house generally costs $18,000-$36,000.

The average cost to add 1000 square feet to a home in the GTA is $300,000 – $360,000.

Choose affordable building materials and finishes, opt for a simple layout instead of a complex design that will cost more in labour time, and consider completing some basic tasks on your own, like painting.

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