IDEAS
Side extension ideas for 2026
Updated 08/26
By: Olivia Scammell
A side extension is one of the most versatile ways to make use of small, narrow, or otherwise unused space around your property.
Done well, it adds genuine square footage and can meaningfully increase your home's market value.
Not sure where to start? Here's our guide to the top styles, trends and design ideas worth considering and costs involved.
Which side extension style suits your property type
What roof style choices mean for the finished look
Whether a single or double-storey extension makes sense for you
How much a side extension typically costs
How much value a side extension can add to your home
Who to call to plan and build the project
Side extension ideas by property type
1. Porch extensions
A pitched-roof porch extension can match an asymmetrical house beautifully, and gives extra space to welcome guests without a major renovation budget. A porch can also double up as a reading nook, extra storage, or a utility space, freeing up room elsewhere and helping keep the rest of the house clutter-free.
Read our side return extension cost guide for a full cost breakdown before you start planning.
2. Bungalow side extensions
Extending a bungalow is often one of the simpler extension projects, since you're only working with one floor. Many homeowners opt for L-shaped extensions, while others go for a T or U layout.
Popular additions include garages, garden rooms, home offices and orangeries. An L-shaped foyer and living room extension, for example, can free up space for a larger driveway while adding real kerb appeal.
Our guide on choosing a builder for an extension has useful advice if you're at the early planning stage.
3. Two-storey side extensions
Two-storey extensions cost more upfront but tend to offer better value per square foot of added space. Depending on the design, they may also require planning permission.
A wood-clad, contemporary two-storey extension can complement the main house while giving you a genuinely separate office space upstairs and an extended kitchen below.
4. Side return extensions
Side return extensions make brilliant use of otherwise dead space alongside a property, often adding a glass-roofed kitchen and dining area that fits seamlessly with the rest of the house. Done well, these additions bring real character without overpowering the original building.
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More side extension styles to consider
5. Single-storey gable extensions
A large gable-roofed, single-storey extension is a great way to add character and space to a period property without over-modernising it. Glazing tucked beneath a roof overhang can allow for French doors and windows that flood the new room with light, while a dark shingle roof can help tie the extension and main house together visually.
6. Terraced house side returns
Even a small terraced house can benefit from a side return extension, adding useful space (such as a utility area) without sacrificing light. A flat roof is often the best choice here, helping avoid any loss of light to upper-storey windows.
7. Sunrooms
Contemporary glass sunrooms work great on modern new-builds. For a touch of period glamour, an orangery or a hipped-roof sunroom with wooden frames and glass panels can work beautifully on both large and small period homes.
8. Semi-detached gable additions
A smaller gable-roofed addition can complement a taller, hipped-roof house while adding a receiving room and kitchen and utility space. Distressed grey-and-white cladding with black-framed doors and windows gives a Tudor-inspired finish that still reads as a considered, cohesive extension rather than a bolt-on.
Planning your side extension layout
If you're considering a side extension, you'll likely already have a space in mind.
But don't forget to think about the roof style early on too. Whether you choose flat, pitched, gable or hipped, it needs to blend seamlessly with the rest of the house.
Our single storey extension planning guide covers all the key considerations, including planning permission guidelines.
Single storey extension planning: Your complete guide
Planning a single storey extension? Our guide contains everything you need to know, including the costs involved, whether you need planning permission, and the key considerations for this project.
How much does a side extension cost?
As a rough guide, house side extensions cost between £1,800–£3,000 per m².
However, for complex designs or very large side extensions, the costs will most likely be higher.
Check out our side extension cost guide below for more details.
How much does a side return extension cost in 2026?
A side return extension can be a fantastic way to utilise wasted space on the side of your house. You can enhance your living space and potentially add value to your home. You can extend your kitchen or living room, or even add a conservatory. In this guide, we’ll take a closer look at the average side return extension cost. This includes the cost of adding a new kitchen in your new extension, plus other cost considerations to bear in mind.
Did you know adding a single-storey extension can add up to 8% to a property's value, while a double-storey extension can add as much as 12%? Check out our how to add value to your home guide to learn more.
Who to call for your side extension
Most side extensions involve more than one trade working together, especially once you get into roofing, glazing and structural work.
A builder will usually manage the main structural work, while a structural architect can help with design and building regulations for larger or two-storey projects. If your extension includes a lot of glazing, bring in a glazier too.
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Hear from homeowners like you
This Solihull homeowner used Mercury Building Services for their kitchen extension:
"MBS were great and I would not hesitate to recommend them. Daryl was easy to deal with and led us, as building ‘newbie’s' through the process from start to finish. Whenever problems arose, normal on any project, we were given advice and direction and consulted about any changes. The team were without exception professional and welcome guests in our home."
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Side extension checklist
Use this checklist to keep your side extension project on track:
FAQs about side extensions
A double-storey extension can add up to 12% to the value of your property, while a single-storey extension is around 5-8%. Adding square footage to your home means more usable space for potential buyers to enjoy.
Costs vary widely depending on size, storey count and finish. Our side return extension cost guide and house extension cost guide both have detailed breakdowns.
Whether or not you need planning permission for a side extension depends on the size, height and location of the extension, as well as whether it falls under permitted development rules. Always check with your local authority or a builder before starting work.
A side extension typically adds new floor area alongside the house, while a side return extension specifically fills in the narrow "dead space" alongside a property, often between a kitchen and the boundary wall.
Extending a bungalow on one side is often one of the more straightforward extension projects since you're only working with a single storey. L, T and U-shaped layouts are all common approaches.
How long a side extension takes to build depends heavily on scope. Single-storey side extensions typically take a few months from groundworks to finish, while two-storey builds can take longer.
Flat, pitched, gable and hipped roofs are some of the most popular styles for a side extension. The main goal is a roofline that blends naturally with the existing house rather than looking like an obvious add-on.
Yes, side return extensions are particularly popular on terraced and semi-detached houses, making use of narrow side passages that often go unused.
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