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Extension layout ideas: How to design the best home extension layout [2024 edition]

Looking for beautiful home extension ideas? We've got them for you...

13 January 2024
7 minutes read

As a homeowner, you want to make the most out of your home extension layout. Additional spaces can help you unlock the potential of your property, while allowing you to create a space that suits your personality.

The planning permission, design and construction stages of a home extension often focus on exteriors, how the neighbours will be affected, whether it’s in keeping with the rest of the area and how it flows with the rest of the building. But it's important to consider how your extension enhances your day-to-day life.

We'll show you how to design your house extension to add space, comfort and value to your home, with examples of inspiring home extension layouts and explanations of why they work so well. We'll also discuss the fundamentals of home extension layout design, the role of architects and some of the inherent complexities.

Good layout configuration will make your home extension look and feel like it has always been there. High-quality design adds value to your property and makes your home a pleasure to live in.

Home extensions types

Working out the best home extension layout for you and your family can be tricky and will depend on the spatial limitations of your extension. First, let’s review the different kinds of extensions:

  • Basement Extensions: Creating a space beneath your home, usually to provide entertainment spaces or additional spaces to your home. This will add an additional storey to your home.
  • Rear Extensions: To the rear of your property, single or double storey in height.
  • Side Extensions: To the side of your property, single or double storey in height.
  • Double Storey Rear / Side Extensions: Adding rooms to your first floor as well as the ground floor, either to the side or to the rear.
  • Wrap-around Extensions: At the side and rear of your property,usually single storey.
  • Dormer Loft Extensions: Extension to the rear roof slope in a box-like style.
  • Hip-to-Gable Loft Extensions: Alteration of the entire roof type to become a larger internal space for conversion into habitable space.
  • Mansard Extensions: Creating additional space by altering the rear roof slope and converting into a habitable space.
  • Additional Floor Extensions: Adding an entire floor onto your property. This also means raising the roof height an extra floor level.

Your home extension brief

Before you decide what type of home extension you want, it’s a good idea to think about what your home is missing. Here are seven questions to help you get started:

  • Do you need more open-plan living space for the family?
  • Do you need additional bedrooms and utility room?
  • Do you need additional bathroom space?
  • Do you want a master bedroom in the loft?
  • Do you need a study or office space?
  • Do you want brighter spaces with more natural light?
  • Do you want the spaces to be more easily accessible?

After you’ve worked out what you need, you should be able to determine what type of extension you want and can start designing your layout.

Why is home extension layout so crucial?

Home extension layouts should always be designed to suit your lifestyle. Families generally require a large, open-plan living and dining room with an extra downstairs WC and a utility room. Sometimes, an additional bedroom or study can elevate your lifestyle.

Interior design and layouts go hand in hand and deciding what you like and how it fits into your property will change the entire space.

Below are some layouts designed by our team, each corresponding to one of the seven questions mentioned above (names are fictional). They should give you some extension ideas and inspiration.

1) Spacious open-plan living created by a rear extension

In their small two-bed semi-detached house, the Martinsons love to cook and spend time with their two young children. Prior to extending, their kitchen had limited space and did suit their activities.

They decided to build a rear extension to provide a large family space where they can cook and relax. With more room, the Martinsons were able to find a little peace and harmony in their day-to-day lives.

2) Two extra bedrooms created by a first-floor extension

The Millers are a retired couple who love spending time with their family. As their grandchildren are growing up fast, they wanted to augment their two-bed terraced house with additional bedrooms for sleepovers.

They chose a first-floor extension above their existing ground floor to provide an additional bedroom. Now, they can comfortably enjoy the company of their grandchildren whenever they choose.

3) An additional bathroom created by a double-storey side extension

The Watsons needed more space for their family to grow and to address the recurring issue of children taking over the bathroom. An extra bathroom would reduce their daily stress levels and add more space generally so they didn’t feel like they were on top of one another.

Once the side extension was constructed, mornings were far less stressful and the family became more cohesive.

4) A master bedroom added by a loft extension/dormer loft conversion

Homeowner Ollie had big plans. He no longer wanted to live alone and wanted to invest in his future. So he bought a house and decided to add a bedroom in the loft for himself, using the two existing bedrooms to let out to rent-paying housemates.

Now, Ollie's surrounded by new friends, has a gorgeous loft bedroom and is earning a return on his investment.

5) An office space constructed by an L-shaped dormer loft extension

Natasha and William moved into to their first home not long before they decided to put in a loft conversion. Natasha, who often works from home, longed for her own space so she could focus on her projects properly.

After some consideration, they decided that an L-shaped dormer loft conversion would create the space they needed. Now, Natasha has a functional home office with ideal working conditions.

6) More natural light created by a single-storey rear extension

Edward and Catherine have lived in their house for years, absolutely adore their garden and wanted to see more of it from all aspects.

They chose to add a rear extension, which gave them increased garden visibility and more natural light, creating a happier, more spacious, light-filled home.

7) Increased accessibility through a single-storey rear extension

Samira had mobility issues and needed a more flexible space. Her house had narrow corridors and it was difficult to access other rooms on the ground floor. An open plan layout and rear extension ensured she could move around with more freedom and carry out daily activities without any impediments.

The role of architects and the extension layout design process

It's essential to discuss your plans with a reputable RIBA chartered architectural firm with proven experience in extension layout design.

Planning your home extension layout design

An architect will help you in the planning stages and assist you in conceptualising the extension by considering interior design as well as the exterior.

A quality architect will recommend building materials and will consider the use of light and space to develop an extension to enhance the quality of your life. A home extension isn't cheap so you should research cost-effective solutions.

The good news is that a well-thought-out and effectively implemented extension creates a home with wow factor! Precise planning in the beginning stages goes a long way toward creating an ideal home.

Problem solving for home extensions

A skilled architect can help you solve difficult problems that seem to have no solutions. Many UK homes were built over 100 years ago and don’t match contemporary lifestyles. People now like kitchen to be the focal point of their homes and want a seamless transition between inside and outside spaces.

With the right home extension and interior design, your new addition will seem like it has always been there.

Consider what your ideal outcome looks like before submitting a planning application. A reputable architect will help you consider:

  • How the extension flows with your existing home
  • How much extra space you will create
  • What to do with the original space
  • How it will look and feel

A strategic design approach will help you create spacious, elegant results.

Design principles for home extension layouts

Architects can help guide you through the design process and interior designers follow best practice principles to ensure high quality. Both will spend considerable time working out the best way to make the most of your home.

Here are the 5 tips on how you can get the same effect quickly:


Balance in a room creates harmony and comfort. By considering symmetry, your extension will look and feel like it has been put together by a professional. You can either use:

  • Symmetrical balance so each half of the room mirrors the other
  • Asymmetrical balance where a more casual feel is achieved
  • Radial symmetry where similar elements radiate out from a centre point

A balanced room will feel stylish and well-designed.


The feeling of light is by far the most important principle when dealing with home extension interior design. People are deeply affected by light, this may hark back to when our ancestors lived in caves, but we typically seek out homes that are bright and light. If lacking natural light, consider using strategically placed, tonal lightbulbs to boost natural ambience.

Focal Point

Set a focal point to create interest and attention. A single point of interest such as fireplace, a widescreen TV or statement piece of furniture adds purpose and a sense of ease and familiarity.


The rhythm of a room is hard to define but looks impressive when you get it right. A specific colour and texture palette can help establish a rhythmic pattern and flow that encourages people to relax and enjoy spend time in the space. An unloved and underused extension is a waste of your money and resources.


Attention to details adds the perfect finishing touch. Tonal colour palettes with pops of contrast and an array of sumptuous, textured fabrics enhance both design and impact. Taking time to make choose harmonious aesthetics will all be worth it when you achieve the desired result.

How it all fits together

As architects, we're trained in a variety of areas to help you keep the big picture in mind so that your home feels like a cohesive, synergistic space, not a series of unconnected rooms.

When you build an extension, you run the risk if it being underutilised. But this doesn’t have to be the case. By connecting the period and style of your existing home to the new extension, your design can achieve a cohesive extension layout with harmonious colour schemes, furniture and wall coverings.

An extension can make you consider redecorating or refurbishing the rest of your home. But it's preferable to wait until it the new addition is complete to get the sense of how the spaces flow together before making major decisions.

Choosing the right architect to create your home extension interior will pay dividends in years to come by enhancing your sense of comfort and peace.

Getting it right

It's wise to always consider the interior as well as the exterior as you'll hopefully live in your home for years to come. Alternatively, when it comes time to sell, your extension will increase the value of your home. So getting your home extension interior design right elevates your lifestyle and property value but get it wrong and you may lose potential buyers and make your space less comfortable.

Take a look at our portfolio to see great examples of imaginative, exciting and inspirational extensions that add character, practicality and value to their respective properties with interior design concept of the highest standard.

Although there's no one formula for achieving optimal layouts, our expertise and experience will help you create the best extension layout by designing a room that fulfils your needs and matches your lifestyle. Your home is your sanctuary where you can relax and escape so it’s important to choose the perfect design for you.

How Urbanist Architecture can help you

Urbanist Architecture is a London-based RIBA chartered architecture and planning practice with offices in Greenwich and Belgravia. With a dedicated focus in proven design and planning strategies, and expertise in residential extensions, conversions and new build houses, we'll work with you to create a home you and your family (or housemates!) will love.

We have so many great house extension ideas, so whether you've got a clear sense of what you want or just know that you need more space in your home, please don’t hesitate to get in touch.

Selena Martin, Architectural Designer at Urbanist Architecture

Selena Martin

Selena is a pivotal member of our architectural team, with extensive experience in new build design, renovations and refurbishments. Selena approaches every project with enthusiasm and thrives in providing clever design solutions to tricky sites.

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