13 Side Return Extension Design Ideas (Plus Your Design and Build Guide)

If you live in a narrow home, chances are you’ve fantasised about what you could do with your side return – that awkward strip of land running alongside your house. Whether your dream’s a bright open-plan kitchen perfect for hosting or an inviting snug where family could gather, the side return extension could be your answer. This nifty addition is becoming an increasingly popular way of maximising available space and increasing natural light. 

Not only do side extensions provide extra square footage, but they can also improve the flow and functionality of your home. Say goodbye to disconnected rooms and hello to an open, seamless layout that truly suits your lifestyle. If you’re thinking about the possibilities for your property, here’s your definitive guide to side extensions: from the different types and the design and build process to costs and ideas. 

Types of side extensions

Single-storey

Single storey side extensions are a popular and relatively cost-effective way to add extra living space to your home. These extensions typically run the length of one side of the house, providing additional space for a living room, dining room or even a home office. Single storey side extensions generally have a simpler design and construction process compared to two-storey options.

Two-storey

If you’re looking to really maximise space, two-storey side extensions do just what they say on the tin: adding both ground floor and upper level rooms. This approach can provide extra bedrooms, en-suites, an office – whatever you like. While more complex to design and build, double-storey side extensions can significantly increase a home’s overall square footage and value.

House types

Terraced house

Terraced houses (Victorian terraced houses in particular) are one of the most common properties that can be transformed with side extensions, as they often have unused space or alleys alongside them. Due to shared boundary walls and party walls, careful planning is required to ensure that the extension doesn’t negatively impact neighbouring properties (block natural light or impede views, for example).

Semi-detached house

Semi-detached homes offer more flexibility for side extensions, as there is typically more open space along one side of the property. This allows for larger, more premium extension designs that can dramatically transform your homex’s appearance and functionality.

Detached house

Detached houses generally have the most straightforward path to side extensions, with fewer constraints from adjoining structures. This freedom allows for bespoke designs that can be tailored to your needs and truly match the property’s architectural style.

Listed building

If you own a listed building, a side return extension can be a bit trickier due to additional planning and design hurdles. What you’ll be able to change depends on the Grade of your building – extensions are usually possible, but there are just a few more hoops to jump through. Getting permission from local  authorities is essential and it’s important to ensure any additions are sympathetic to the original property.

The design and build process

Initial planning and research

The first step is to carefully evaluate your home. What would you do with the extra space and what’s your budget? Researching planning regulations, permitted development rights and common side extension designs in your area can give you a good idea of what’s possible. If your neighbours have extensions, chatting to them is a good place to start. 

Engage professionals

For most side extensions, it’s recommended to work with an architect or architectural designer to create the initial concepts and drawings. They can also advise on the planning process and liaise with local authorities. Depending on the scope of your project, you might also need to bring in structural engineers and quantity surveyors at this stage.

Design development

Once you’re clear on what you want from your extension, you can refine the design with your architect. They can help you optimise the layout, make sure it’s integrated with your home and advise on how best to achieve the desired look and feel. This phase includes finalising the floor plans, plus creating elevation drawings and 3D visualisations.

Planning permission and legal requirements

Depending on the scale of your side extension, you might need to get planning permission from your local council. Some extensions fall under ‘permitted development’ which allows you build without planning permission, but you have to meet strict criteria:

• Your side extension is max 4m high, with eaves height 3m or below
• It has a width that’s less than half of the original building
• It’s less than 2m from the boundary of your property

Each process has their nuances, so it’s best to look to your architect for advice, and to ensure compliance with building regulations.

Technical drawings and specifications

The next step is developing detailed construction drawings which include structural calculations, services integration and material specifications. These technical documents will be essential for your contractor to refer to during the build phase.

Cost estimation and budget finalisation

An experienced quantity surveyor can provide accurate cost estimates to help you finalise your project budget, factoring in any necessary wiggle room. 

Contractor selection

With the design and planning in place, it’s time to choose your contractor – taking into account their portfolios, timelines, warranties and reviews. This is one of the most important decisions you’ll make. Knowing how and where to begin your search can feel like a minefield, particularly if you’ve never done any work to your home before, so it can be tempting to commission a friend or family member’s recommendation instead. However, no two extension projects are identical, so it’s worth putting the time and effort in at the beginning of your project to find a contractor that has the skills and experience for your unique requirements and timeline. When you get the right match, the renovation process is exciting – as it should be. Trusting your contractor and being able to lean on their expertise throughout the journey is a huge stress-reliever.

If you need a hand finding a contractor for your extension, The Page can help. Book a free call to tell one of The Page’s renovation coaches about your project and we’ll get back to you within 24 hours with three Pager (pre-vetted contractor) recommendations tailored to your needs and budget. Our Pagers are some of the best in the business: experts in their field, reliable and always willing to go the extra mile. We catch up with them daily, so you have an extra set of hands to keep your project running smoothly and to time.

Take a look at Pagers’ extensions

Construction phase preparation

Before breaking ground, ensure you have all necessary building approvals, finalised contracts with your contractor and a detailed construction schedule. It’s worth speaking to your neighbours too, as there will inevitably be some noise and disturbance while work is happening. 

Construction and project management

Throughout the build process, regular site visits (if you’re living elsewhere) progress meetings and quality checks will help ensure that your vision is brought to life just as planned. Your architect should also be able to help you out with this, checking in with your builder and assisting if any unforeseen issues pop up. 

Using an architect

Engaging an architect is recommended for most side extension projects. Their expertise in design, planning and project management can help you achieve the best results, both functionally and aesthetically. The documentation needed can also be complex, so it helps to have an architect’s words of wisdom – they can advocate for you throughout the process.

13 ideas for side extensions

1. Keep brickwork exposed for an industrial-chic look

In this sleek kitchen, leaving new brickwork exposed adds to the stylish industrial feeling. Plus you can cut costs on prepping and painting the wall. 

2. Add a breakfast bar for relaxed meals

The great thing about a side return extension is that you can optimise space to suit your lifestyle. Here, more square footage allows for a colourful breakfast bar for a casual bite to eat or a glass of wine. 

3. Create a cohesive look by reflecting the original building’s design

Black paintwork and the use of similar-coloured bricks on this extension blend the new addition perfectly with the original building. 

4. Replace a wall with glass

The more natural light a room receives, the bigger it will look and feel. Here glass doors frame this small side rextension, creating an even more open feeling.

5. Think lengthways

Unless you’re knocking through walls, side return extensions are typically long and quite narrow. Play to this with your design by installing fixtures lengthways to maximise space. 

6. Make use of mirrors in your side extension

Take design cues from this thoughtfully styled kitchen, where the big mirror reflects light and provides the illusion of extra space.

Read Tessa and Tom’s extension story

7. Use colour outside and in

Don’t forget to style the outside of your extension, too. Brightly coloured paintwork is a relatively cost-effective and quick way to add character, ensuring your home looks as good from the outside as it does inside. 

8. Skylights, skylights, skylights

Multiple skylights let in as much natural light as possible, plus are interesting design features in their own rights. A win-win. 

9. A neutral backdrop lets colours pop

Opting for light-coloured paint, fixtures and flooring creates a lovely blank canvas that allows certain features to pop – like the bright blue table legs here. Don’t feel like you have to stick to white, soft pinks, creams and greens can work equally well. If you’re creating a side extension with the hope of adding value to your property to sell further down the line, keeping things neutral can be a good idea for mass appeal.

10. Create a reading nook

With extra square footage to play with, why not add storage and style? A bespoke bench offers the perfect spot to sit and read, plus space inside for stowing away kitchen appliances or other odds and ends.

11. Bifold doors blend outside and in

Bifold doors are a popular choice as they offer a seamless transition from your house extension into the great outdoors. They’re also compact and space-efficient, as well as being easy to maintain.

12. Inbuilt benches and shelving maximise space

In this contemporary side return, in-built shelves and a dining bench make clever use of space, while adding to the clean, sleek look achieved by the simple black-framed windows.

13. Combine period features with modern elements

When done sympathetically, older properties can absolutely be extended with more modern elements – it’s all about the details. In this instance, the brickwork has been matched to the original building for  a cohesive look and the simple patio doors blend seamlessly into the facade.

Read James’ side return extension story

Potential costs

Side extension costs can vary widely depending on size, complexity and location. As a general guide, single storey side extensions typically range from £1,500 to £2,500 per square metre, while two-storey extensions can cost between £2,000 and £3,000 per square metre. Additional factors like material choices, site access and planning requirements can also impact the final price.

If you live in London, you can expect to pay a premium. Learn more about side return extension costs in London.

Will a side extension add value to a house?

In most cases, the answer is yes. A well-designed and executed side extension can significantly increase your home’s market value, typically by 10-20%, and sometimes more. The added living space, improved layout and enhanced curb appeal are all features that make a property more attractive to potential buyers.

Find an extension contractor

If you need a hand navigating the renovation process and finding the right contractor, The Page’s renovation coaches are here to help. Just tell us a bit about your project on a free, no-obligation call and we can recommend Pagers with skills and experience perfect for your project within 24 hours. All of our Pagers are highly-skilled, reliable and ready to help turn your extension visions into reality, stress-free. Throughout the journey, you can lean on The Page for support and guidance – from help deciphering quotes to tips on timeline planning. Plus, enjoy added peace of mind knowing we’re checking in with our Pagers daily and getting regular updates on your project’s progress.

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