With the cost of living soaring in Canada, it should come as no surprise that many Canadians are investing in home renovations to improve their quality of life. In fact, recent data indicates that about half of Canadians have completed or are planning on completing home renovations, including additions.
If you are among your fellow Canadians considering a home addition this year, you’re likely wondering about the average cost of home additions in 2025. In this blog, our home addition contractors in Southern Ontario have shared an expert look into the cost of adding a room to a house. So, continue reading our home addition cost guide to learn what to expect, including factors that can affect your budgeting for home additions.
When looking into the costs of home additions in Ontario, it can be challenging to make heads or tails of the various elements that go into determining the average cost. This is not anything new, as individuals often also find it difficult to determine the cost to build a custom home.
With us at Ever After Homes, the cost of your home addition is linked to the custom home cost per square foot. Here is what you can expect:
For a second-storey addition, you can expect to invest anywhere from $400,000 to $900,000 or more, with an average cost of $300 to $400+ per square foot. This includes everything from structural reinforcements to high-end finishes like custom cabinetry, quartz countertops, and premium hardwood flooring with intricate inlays.
Accessory dwelling unit (ADU) additions, whether attached or detached, align closely with custom home building costs. Detached ADUs are typically priced per square foot.
The price range for these projects can vary significantly. Mid-range custom additions cost between $800,000 and $1,200,000+, and square-foot pricing is between $400 and $600. Likewise, high-end custom home additions can cost between $1,500,000 and $3,000,000, with square-foot pricing ranging between $600 and $900+.
This is the same pricing you should expect if you want to build a custom home with Ever After Homes, but of course, these costs can change based on your project needs and the scope.
Quite a few factors can influence the cost of building a home addition in Ontario. If you understand these factors, it can help you make a better decision about your home addition project. Let’s dive into the most important factors known to affect addition pricing below:
Project size and scope: This might be a no-brainer, but the size and scope of your project can affect how much you will pay. For example, the bigger your addition project, the more you’re likely to pay, but since this isn’t always the case, it's a good idea to speak with a trusted builder in Southern Ontario like us.
Material selection: The types of materials you choose for your addition can impact how much you pay for custom or high-end features, increasing the cost of home extensions near Ontario. For example, if you choose materials like marble flooring or countertops, custom trims or cabinets, and energy-efficient doors and windows, you will pay more than those who choose budget-friendly alternatives.
Labour and expertise: Experienced Ontario-based contractors often charge more than general contractors, which is another consideration. However, higher costs usually mean better quality, communication, and build timelines. In addition, Ontario's seasonal construction services may also impact the price of your addition.
We know that no one likes to be given a quote for a home addition only to find out later that the actual pricing has increased and is higher than expected.
Unfortunately, this scenario is more common than many might want to admit, especially in the home building industry in Southern Ontario. This is because hidden costs could arise, and many are at no fault of the builders.
Understanding these potential hidden costs ahead of your addition project will help you plan for unpleasant surprises and help you budget better. So have a look below at the hidden costs we often warn our loyal clients about before they begin an addition project with us:
In our experience, unforeseen repairs or structural changes are one of the most common unexpected costs during home addition builds. In many instances, we – and other contractors – find that once walls are opened up, several issues arise, like dry rot, outdated leaking plumbing, mould, or structural weaknesses.
Each of these issues has to be addressed before an addition project can proceed, and in many cases, these problems can significantly increase overall project costs. That’s why we recommend discussing with your contractor what these potential issues might cost you before your project begins. Having an open conversation will help you budget accordingly and prepare for unexpected expenses.
If you’ve decided to finance your home addition, remember that loans and financing come with extra processing fees. For example, you will be responsible for paying interest fees, which can sadly add up over time.
In addition, a lender might require an appraisal and inspection of your residence before they approve a loan. These both introduce additional costs over and above what you budget.
So, if you are going this route, we recommend you shop around and consider all financing options and their repercussions before securing finances for a home addition project. Often, a little looking can be the difference between finding a loan with more favourable terms and one that puts you under financial strain.
Home additions in Southern Ontario are well worth the investment, considering they bring numerous benefits. Some of these benefits include increased home value, more space, improved use of a home, and better curb appeal.
However, we understand that the cost of home expansion in Southern Ontario could be holding you back from embracing your dream of an improved living arrangement. We hope that the average home addition costs in Ontario that we discussed will paint a clearer picture of what to expect when building a new second-storey addition or ADU.
If you would like a personalized quotation and have more questions, our team at Ever After Homes is happy to help. Simply contact us here, and let us help you improve your quality of life with a home addition you’ll love.