Home Addition or Extension—What Are the Main Steps?

There are plenty of reasons to feel like the home you own isn’t quite fit for your needs. Are you lacking space on account of your growing family or an expanding furniture collection? Have you decided to work from home and need space for an office? Are you considering adding a home gym, laundry room, or greenhouse? Whatever the case, a home extension or addition is a great option if you’re lacking space and looking to add some square footage. 

Naturally, homeowners who aren’t well-versed in architecture or interior design may find the initial stages of this project challenging. This article is an overview of the steps to follow to build your home addition or extension and take on this new, exciting chapter in your life!

What Are the Steps of a Home Addition or Extension Project?

1- Budget: How much does a home extension/addition cost?

First things first, start by determining how much a home extension will cost. When taking on larger renovation projects, it’s important to stay within a clearly defined budget. Do remember to offer yourself a little bit of leeway for any mishaps or changes, as these are common in almost any renovation project. A budget can be clearly defined once you figure out several key aspects, including:

• Shape and size of the extension/addition

• Materials you’ll be using

• Contractors, architects, or designers you’ll hire

• Construction system or process you’ll adopt

• Whether the project is turnkey

Once these factors have been determined, you’ll have a better idea of the overall budget needed. One of the easiest ways to lay out a baseline budget is to calculate the price per square foot. 

2- Submitting a building permit request

It’s also very important to understand the time and effort that goes into such a large-scale project. Plenty of research should be done before jumpstarting, including figuring out what permits you’ll need. Permits will differ from one municipality to another. It’s paramount that you apply for these well before your projected start date, while also setting a realistic project timeframe. Going into this project as well-prepared as possible means being equipped to take on any challenge ahead.

3- How to build a home extension or addition

You likely already know what type of home extension you plan on building, but here’s a quick overview of the three main types for a more in-depth overview of the available options.

Building Up: Adding a Storey

As you’d imagine, this type of addition means adding another storey. This is usually done by adding another level where your roof currently sits, and thus, involves tearing the roof off. Once a second storey is built, a new roof will be built atop it.

Building Out: Straight On, Left, Right, or Out Back

As with building up, building out involves adding space to the rear, side, or front of your house. This is done by following the existing foundation to the back or side. Naturally, you will need to build a new foundation where the extension will sit.

A Detached Extension

A detached unit can take on many forms, including a guesthouse, office, studio, garage, or carport. Such spaces may also be dedicated, first and foremost, to storage. In most cases, they don’t require a foundation.

Extension Built on Pole Footings, Concrete Slab, or Foundation (Full Basement or Crawl Space)

Several methods can be used based on your needs, budget, and land characteristics. Here’s an overview of the three main home extension methods:

• Extension on foundation (full basement or crawl space): This type of extension consists of digging around the current foundation and pouring a new section of the foundation. This ensures structural stability and excellent insulation, but costs may be quite steep given the complexity of the job.

• Extension on concrete slab: Using this home extension method, a concrete floor is poured, serving as the extension’s base (like a patio). It’s a cost-effective alternative to a foundation-built extension, lowering costs related to concrete, excavation, and labour.

• Extension on pole footings: With this one, the new structure is upheld by pilings screwed into the ground, adjacent to the existing structure. This home extension option is more affordable, albeit it does come with some challenges in terms of insulation and long-term stability.

4- Contractor, architect, or both?

Now’s the time to determine who you plan on working with and hiring for your home extension or addition project. For most homeowners, taking on this project alone isn’t feasible. Instead, we recommend hiring a contractor, architect, and even a structural engineer. Below we’ll break down why you may choose to work with one or the other.

Contractor

The right contractor will help you with your home extension project from start to finish. In many cases, they can help with permits, material choices, creating a structured timeline and realistic budget, as well as the building process itself. Most contractors will have access to a network of professionals and thus can assist you in hiring who you need to make this project run smoothly. If you’re looking for a trusted contractor, do your research or ask family and friends for suggestions.

Architect

A contractor can assist you in finding the right architect for the job. In many cases, hiring an architect will be necessary for your permit requests, as they’ll have to draw up blueprints. These drawings will be used throughout the building process and in some cases, the architect will work with or suggest an engineer who can carry out the extension’s structural design. If you’re lucky, the architect may also create a 3D rendering of your extension to give you a glimpse of the final result.

5- Building inspections

Since this is a large-scale project, you’ll likely be required to schedule periodic building inspections to ensure that each step is carried out safely. In many cases, the contractor you’re working with will be able to schedule and look after these inspections on your behalf. The nature of the inspections will largely depend on the project, but every home extension/addition will require a final inspection for both the interior and exterior. Here are some other potential factors to consider during the inspection:

• Foundation

• Structural framing

• Insulation

• Gas, plumbing, and electrical wiring

• HVAC

• Final interior and exterior inspection

Home Addition or Extension: A Step-by-Step Process

Building a house extension or addition successfully requires careful planning. Key steps include:

• Assessing your needs

• Hiring professional help

• Getting the necessary permits

• Drawing up detailed plans

• Diligently managing the building site

By following the steps outlined, you can turn your vision into reality. Not only will you gain living space, but you’ll also be adding value to your property.

Feel up for the challenge? We hope that this article gave you some helpful insight into what to expect!

Don’t forget to check out our article: Home Addition Project: Checklist.