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House Extension Project: What You Need to Know

Last modified: 2022-04-28 | Approximate reading time 5 mins

Of course, we know that you probably love your home! But as time passes, your family might expand, you might collect more items than there’s space for and so on. Therefore, the same house you bought a few years ago could easily become too small to align with your current needs. 

While the thought of moving out could be too much for some, you may consider renovating and taking on a home extension. If this is the position you find yourself in, then you’ve come to the right place. Our article will explain everything you need to know about building a house extension.

Everything you need to know about home extension projects!

Planning a house extension project: the main things to take into consideration


source: unsplash

As you’ve likely guessed, adding an extension to your house is a great way to create more space for your home's layout. However, there are many different ways to approach this project, and these will be dependent on the layout of your home and property as well as the space available to you. 

In the majority of cases, the most common will involve adding living space above the garage, to the side of or to the back of the building. In some cases, pre-existing spaces such as a porch can be converted into a house extension.

Another option is to add a new floor or home addition. However, this way of adding space will be more expensive since you’ll have to remove a portion of your roof as well as knock down a few walls. If this is the option you choose, you’ll need to be sure to plan enough space on the first floor for the staircase that will lead to the new floor. 

Again, the decisions you make regarding the steps of this project will depend on what you're looking to achieve as well as the resources available to you.

Determining what you are looking for

It’s no secret that this type of renovation project is major and thus will involve a lot of planning. Before actually launching any solid renovations, it is important to first identify your needs. Ask yourself these key questions, including:

  • Why do you want to extend your house?
  • Do you need new rooms or is it because you don't have enough space in your current rooms?
  • How much are you comfortable spending?

Knowing what you want is the most important part of the planning process.

Once these questions have been answered, it will allow you to further work on and determine a budget. From the get-go, it’s important to be realistic about how much money you want to invest in this project.

Setting a fixed budget with a small amount of room for any mishaps or grievances will allow you to find ways to finance your renovations and prevent you from experiencing a financial crisis.

We’re suggesting that this type of renovation project can cost anywhere between $24 000 and $240 000, depending on the scale as well as the chosen materials. (for more about the budget of a home extension project, check out The cost of a home addition project).

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Professionals and permits for a home addition project

Once you're past these initial steps of planning out the details of the project, we’d recommend that you contact an architect or an engineer who can create and draw up plans for your house extension project. 

You’ll be able to talk about your project with them and see if your ideas are feasible as well as creating any alterations to your original plans. Working with an architect or contractor can offer you a point of view outside of your own while helping you find the best alternatives.

Once an architect or professional has drawn up detailed layout plans, it will be your responsibility to contact your municipality or city in order to obtain a construction permit. Based on the drawings made by the architect or the engineer, your municipality will decide if you can move forward with this project. 

If so, they will issue you the right construction permit. It is crucial that you do not move forward with this project before obtaining the proper permits! In most cases, municipalities will not accept home extensions that are added to the front of a building.

As we mentioned in our first paragraph, you’ll probably have to create an extension from the sides or from the back as well as adding a new floor altogether.

Last but not least, look for a qualified contractor who has knowledge and expertise about the general structure of a house. In some cases, especially where rerouting plumbing and electricity is involved, you may need to hire more than professional. Meet different contractors and ask them to give you quotes.

An estimate of the costs involved in a home extension project

  • Turning a roof into a floor : $150- $300 / sq.ft.
  • Extra floors: $120-$240/sq.ft.
  • Installing collar beams: $35-$60+ each
  • Installing lateral bracing on collar beams : $120 - $240 +
  • Replacing a cover support: $5 - $8/sq.ft.
  • Adding an extra floor: $120 000 +
  • Adding a floor over a garage: $60 000
  • Adding a room over a ground floor: $70 000
  • Cantilever expansion: $30 000
  • Installing an interior wall with door opening: $600 - $1200 +

Building a home extension involves complicated financial calculations. This process includes fixed fees, which means that a smaller expansion can have a higher price per square foot than a big one. However, the fewer square feet, the lower the full cost of the expansion will be, and this is due to the cost of materials. 

When all is said and done, the cost of a home extension won't matter as much when compared with the benefits of living in a comfortable way. 

Extension de maison_home extension project

Photo: Fotolia

The different ways to expand your home

As we’ve mentioned, there are several different types of home extensions. Simply adding a side or back extension on the structure is expensive, but adding one or several floors is even more expensive. It’s often easier to build a home addition over a garage. 

Depending on your needs and on the municipal rules that are currently in effect, you can increase the size of your home by taking over the backyard. 

If you’re just looking for a little bit of extra indoor space, there are plenty of projects you can conceive without necessitating a complete overhaul. Why not consider transforming your back porch into a sunroom?

This glass-enclosed space will allow you to enjoy your backyard during the cold season, whilst adding more space to your kitchen or living room. Ideally, the extension will be done over the whole length of the house without affecting the architecture.

There are several other types of home addition ideas you might be interested in, and these include adding a basement, building a garage, building an extension on foundations, home addition on stakes and home addition on a concrete slab.

For more information about home extensions, check out the following articles:

Get 3 renovation quotes for your home extension project can help you get quotes for your house extension project. If you submit your project to us, we’ll put you in contact with contractors that are the most suitable for you. Fill in the form on the homepage ( it only takes a few minutes), and you will receive quotes from companies that are specialized in-house extension projects.

Dial 1-844 828-1588 to speak with one of our customer service representatives


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