Top 5 Inspiring Single Storey Extension Ideas for Your Home

A collection of top single story extension ideas designed by Essex architects, showcasing modern home extensions, rear extensions, and open-plan living spaces.

Top 5 Inspiring Single Story Extension Ideas for Your Home

A single storey extension opens up endless design possibilities, giving plenty of choice and options to design around yours and your family’s needs. We love working with homeowners to select innovative materials and unique designs that make each house extension truly one of a kind.

Want to discuss your single story extension ideas? Feel free to arrange a free 30 minute consultation with one of our experts.

Modern single story extension ideas by Essex architects featuring open-plan layouts, kitchen extensions, and bright family living spaces.

Single story extension ideas

Choosing the right design can be challenging with so many options available. To spark your creativity, we’ve put together our top 5 inspiring single story extension ideas. Each idea comes with insights on planning permission, construction costs, and real design examples, proving that even small changes can have a big impact.

With thousands of projects under our belt, we’re Essex Architectural designers who know a thing or two about transforming homes. Let these inspiring single story extension ideas guide you in creating a space that not only meets your practical needs but also elevates your entire living environment.

Side single story extension idea designed by Essex architects, adding extra ground floor space with smart use of side access and open-plan design.

Side - Single-story extension idea

One inspiring single story extension idea is a side extension. To achieve this, you don’t need as much space as you might think. Adding just 2–3 metres to the side of your house can create a surprisingly significant difference in your living area.

Knocking through the existing side wall not only adds extra room but also cleverly utilises the wall’s own width and length. It’s a simple, yet effective solution that often takes homeowners by surprise, proving how easily you can create that much-needed extra space.

Single story extension build costs

This approach is one of our top picks among single story extension ideas. For more guidance with build costs, click here.

Breakdown of cost factors for a single story side extension by Essex architects, including size, materials, and structural design considerations.

Cost factors for a single story side extension

Often drainage runs parallel with the back of the house, leaving the side relatively manhole-free. This can save time and money during the build, as moving manholes usually costs between £2,000 and £3,000, depending on how many pipes are involved.

A rule of thumb in 2025 for single story side extensions is £2,000 per square metre. For example, if your extension is 3m x 6m, that’s 18m². At £2,000 per square metre, the base cost comes to £36,000, with VAT bringing the total to around £43,200.

Local architects

This single story extension idea adds valuable width to narrow houses, often transforming the home completely. A comment we frequently hear from customers after their builds are complete is that they feel like they live in a completely new house. When considering single story extension ideas, even a modest side extension can deliver dramatic results, if the architectural design is done right.

Illustration of the pros and cons of single story side extension ideas, highlighting space benefits, access trade-offs, and planning tips from Essex architects.

Pros and cons for single story side extension ideas

Side access

Adding a side extension can sometimes reduce or remove side access to the garden, so it’s important to weigh up how much that access matters to you. Like many single story extension ideas, side extensions can come with a few trade-offs, but the added space often outweighs the compromises.

Garden space

A key benefit of this single story extension idea is that it doesn’t cut into your main rear garden, leaving you with more space to enjoy during the summer months. The area down the side of a house is rarely used for more than storage or a walkway to the garden, making it a smart space to repurpose.

Spatial perception

Most houses are longer than they are wide, so adding a single story side extension often creates more squareness to your home. Even if the m2 area is the same, a squarer space will feel larger than a rectangle space.

Looking for single story extension ideas tailored to your home? Use our instant design cost calculator to get a quick estimate.

Rear single story extension ideas by Essex architects, showing extended kitchen and living spaces with improved access to garden areas.

Rear - Single-story extension ideas

The most popular single story extension idea, largely due to the layout of most properties. A rectangular plot with limited side space often leaves the rear as the most practical option. Some of the finest extensions we’ve designed have been rear single story extensions, and with over 30 years of combined experience in architectural design, we’ve refined the process to a T. Let us guide you further on rear extensions, and feel free to get in touch to see if this single story extension idea is the right fit for your home.

Roof styles

The are many roof style to choose from for a single story rear extension. Some roof style will affect the price of the build and potentially the type of development consent application. We can advise more of this if you have any questions.

Different roof styles for rear single story extensions, including pitched and flat roof options designed by Essex architects for modern and traditional homes.

Rear extension roof styles - Single story extension ideas

Flat roof extensions

This used to be the cheapest roof option, but changes to building regulations have levelled the playing field. With the thermal performance requirement shifting from 0.18 W/m²K to 0.15 W/m²K, the cost of a pitched roof extension is now similar to that of a flat roof. This change forms part of the Future Homes Standard 2025. Many customers worry that flat roof extensions might feel lower in height, but by matching the existing ceiling level and incorporating skylights, the space can feel just as open and spacious as a pitched roof extension.

Pitched roof extensions

This single story extension idea works best if you’re not planning to extend beyond 3.5 to 4 metres. That’s because common clay or concrete tiles require a roof pitch of 15°, so the further the extension projects, the higher the roof will rise as it meets the existing house. A minimum clearance is needed below first floor windows, which is why a flat roof extension is sometimes the more practical choice. That said, a pitched roof extension with Velux-style roof windows can feel bright, open, and airy. If the budget allows, many of our customers say electric opening roof lights are a game changer for ventilation and ease for opening and closing.

Gable roof single story extension designed by Essex architects, featuring a pitched roof, vaulted interior, and large glazed gable end for natural light.

Gable roof extensions

This extension roof idea is a pitched roof with two sloping sides that meet in the centre. It creates a triangle shaped roof with both slopes equal in pitch. The nice thing about these roofs are that they match the existing house roof style and are very spacious inside. This single story extension idea allows for plenty of natural light as the roof can consist of velux stly windows and a striking glass gable front. More costly than a flat roof and pitched roof extension due to the additional steel and timber work. the gables window also cost around £2,000.

Hipped roof extensions

A single story extension idea that typically costs £4,000–£5,000 more than a flat or standard pitched roof extension. The hipped roof design works particularly well with side return extensions, as the slopes align neatly and allow snow and rain to run off easily. Skylights along the return can bring natural light into the rear rooms of the existing house. Visually, it’s a striking roof style, and when designed by experienced local Essex architects, it can truly elevate the overall look and feel of your extension.

Wrap around single story extension designed by Essex architects, creating L-shaped open-plan living with extended kitchen, dining, and family space.

Wrap around - Single story extension ideas

A wraparound single story extension combines a side and rear extension to create an L-shaped space that opens up the home in an effective way. It’s a popular choice for those looking to extend the kitchen and add a dining area to create an open-plan layout.

 This single story extension idea is great for making better use of the full width of the plot, especially if there’s unused space down the side. It can really change how the ground floor works day to day, without needing to move or add an extra floor.

Internal remodelling

This single story extension idea can add a significant amount of additional living space to the ground floor. With the help of experienced Essex architects and structural engineers, you can completely remodel the layout and create a new home that works for you.

Open-plan layout

Because this single story extension idea adds both width and depth, removing sections of the existing house walls creates the opportunity for a large, open-plan layout. We’ve designed many wraparound extensions where the kitchen, dining, and living areas flow together as one continuous space. A separate snug room is often included at the front of the property too, providing a quiet spot to relax when needed.

Scope for a 1st floor extension

The foundations for the side section of a wraparound extension can be designed with a future first floor in mind, ideal if you might want an extra bedroom later on. Many of the roof materials removed during the first build can often be reused for the new first floor roof, helping to reduce waste and recycle wherever possible.

Happy couple representing satisfied clients who chose Kirkwood Essex architects for their single story extension design, shown above verified 5-star customer reviews.

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Jack Dev
08:58 04 Mar 25
I was looking for an architect in Billericay and came across Kirkwood. They designed my single-story rear extension, which includes an open-plan kitchen and an internal knock-through. The architects and structural engineers were fantastic and really understood what I wanted to achieve. Kirkwood also put me in touch with local builders who were reasonably priced and completed the extension without any fuss. If you’re looking for a reliable Essex architect serving Billericay, I’d definitely recommend Kirkwood.
Maria Krystal Humphrey
11:20 03 Feb 25
We had a single-story house extension built in Thurrock, Essex, by the builders that Kirkwood passed us onto. Kirkwood's architects did a really good job, so we were pleased we went to them rather than a design-and-build company that just subcontracts the architectural work out.
Grace Biddiss
09:27 02 Feb 25
We appointed Kirkwood as our architects for a double story and wrap around kitchen extension in Billericay, Essex. They provided us with architectural plans, structural engineering and building regulation drawings. The team was professional from start to finish and the builder they recommended has done a faultless job. You definitely get what you pay for, highly recommend. Thanks!
Freyja
19:14 01 Feb 25
We’ve worked with residential architects before, but Jamie and his team, especially Nathan, were fantastic. Kirkwood designed plans for our double-story side extension, loft conversion, and single-story rear kitchen extension, and we knew we had to choose the right company since it involved our entire home.Based in Brentwood, Essex, we were also introduced to builders and tradespeople through Kirkwood, and they were excellent—professional, respectful, and a pleasure to work with. If we ever take on another project, we wouldn’t hesitate to use them again.
Harry
14:41 01 Feb 25
I was skeptical about Kirkwood’s 5 star reviews but now I’m one of them. Incredible service, especially for the money we paid. They wasn’t the most expensive but for the standard of service we received, they defiantly should have been. They done the architectural plans for our home extension in Chelmsford. The architect was amazing at creating our open plan kitchen and dining area. The structural engineer was quick, polite and drunk tea like it was going out of fashion. Strongly recommend if your considering a architect for your home extension in a Chelmsford.
Riley Russell
13:58 31 Jan 25
Kirkwood done a fantastic job on our architectural plans for our new single story kitchen extension in Brentwood. They gained us approval from the council and also provided the structural engineering for the project. We used their recommended builder who so far, we cannot fault one bit. Thanks again and highly recommend.
iansalsbury
10:54 24 Jan 25
The Kirkwood team were a pleasure to work with and have in our house. What can be a stressful time was made a lot easier by a team who build with quality, communicate clearly, and address and action any questions you raise....however small or large.We now have an amazing extension, and would be happy to use the team again.
Natalie Moore
12:29 23 Jan 25
Jamie and team are always helpful and very knowledgeable. Work on our kitchen extension carried out professionally and to high standard from design to build completion. A fantastic job, and very pleased. Many thanks
Kelly Pye
08:27 22 Jan 25
Jamie has provided lots of advice on house improvements including different options for extending as well as the possibility of a loft conversion. He responds quickly to queries and is full of knowledge! I wouldn’t hesitate to recommend him
Boris
19:35 12 Nov 23
Kirkwood Design and Build Builders, Wickford did a fantastic job on our extension in Billericay. They helped with planning permission, design, and build. Professional company through and through. Given that we haven't done such a large project before, we were a bit nervous and had a lot of questions. Jamie and his team from Kirkwood Design and Build Builders was good putting us at ease and now that we are fully complete with all our work, we further appreciate how professional this company is. Would highly recommend.
Holly Luckin
09:29 11 Nov 23
Nothing was to much hassle and Jamie is lovely!
john rocke
11:33 09 Nov 23
Great company and very professional. Nothing was a problem, very helpful and will definitely use them again. Have already given their details to a friend of mine.
Dave Lynch
19:32 08 Nov 23
Work carried out to a very high standard, very pleased with the results.
Sharon Gormer
13:06 07 Nov 23
Very professional company, helpful and friendly staff.
Aaron Tutton
11:15 07 Nov 23
Great builders, very professional and perfectionists! Thank you for such an amazing job
Olly Tait
13:28 21 Apr 23
Jamie and his team were so profesional from start to finish and made the job a joy to watch our dream come together.Very knowledgeable and contactable throughout the process.Couldn't ask for a better outcome and value for money.Will definitely be recommending and 100% will use again!5 star!!!
Sandie
20:03 20 Jan 23
I highly recommend the Kirkwood team! Exceptional workmanship, clear communication, Jamie & his team have provided the utmost as a polite & professional team! Very satisfied customer, looking forward to planning our loft conversion this year with you guys! Many thanks!

Want advice tailored to your home? Chat with a Kirkwood expert about your project today.

Flat roof - Single-story extension ideas

In most cases, you won’t need to apply for planning permission for a flat roof rear extension, as most fall under permitted development. But there are some exceptions to this rule, if you live in a flat, maisonette, or conservation area, you may not have permitted development rights and might need to apply for planning permission.

This single story extension idea has a more modern look, using clean lines that match the doors, windows, and walls. For more on contemporary single story extensions, take a look here.

Overview of the pros and cons of flat roof extensions, with insight from Essex architects on cost, style, insulation, and build speed for single story extensions.

Pros and Cons of flat roof extensions

Clean Lines and Contemporary Style

Flat roof extensions have a more contemporary and modern appearance to them. Since the regulation upgrade in 2023, the roofs are now much thicker, whereas before, flat roof extensions looked wafer-thin and lacked proper insulation. Now they have a grander look, with deep fascias creating a bold, box-style roof that adds presence and architectural interest to the rear of the home.

Everything's square

We try to cover it all when it comes to single story extension ideas, and here’s one that’s not often considered. Nearly everything within the line of sight when viewing the back of the house from the garden is square or rectangular. the doors, windows, bricks, internal and external walls, first floor windows, even the paving slabs and fence panels. A flat roof continues that same geometry, reinforcing a subtle design consistency. It’s an unspoken detail that often goes unnoticed but makes the overall design feel balanced and intentional.

Flat roof extension by Essex architects, highlighting cost-effective single story extension ideas with faster install times and modern design.

Cost and install time

This is still the most cost-effective roof type on the market. Forget the old tales about flat roofs leaking, modern materials have made them some of the best-performing options for single story extensions. Their quick installation time is another major benefit, making this single story extension idea both practical and budget-friendly.

Parapet option

When tight to a neighbour who already has an extension, getting down the side to clear gutters can be awkward. A parapet wall not only adds character to the extension but also reduces the need for visible gutters. While a spigot is still required to transfer rainwater from the roof outlet to the downpipe, you won’t need gutters running around the entire roof edge. This single story extension idea works especially well for flat roof extensions and helps maintain a cleaner, more modern look.

Modern flat roof extension ideas for single story extensions, designed by Essex architects to maximise light, space, and contemporary style.

Flat roof extension ideas - Conclusion

Flat roof single story extensions have improved a lot over the years. Better materials and smarter design have made them a popular choice for adding space without spending too much. They look modern, suit most homes, and are often quicker and cheaper to build. You might need to check them now and then for maintenance, but overall, they’re a solid option if you want more space without the big cost.

Pitched roof - Single-story extension ideas

We’ve all seen single story extensions, but not everyone has come across a vaulted pitched roof extension. The pitch refers to the angle of the roof, and in this case, it’s usually set at a minimum of 15 degrees. Pitched roof extensions are often chosen to give a more traditional look and help the new space blend in with older-style homes.

Single story kitchen extensions

Instead of building a flat ceiling inside, the modern approach is to follow the slope of the roof with plasterboard and add Velux-style windows. This makes use of the full height, bringing in more  natural light, especially helpful if it a kitchen extenson. In our opinion, it’s the only way to do it.

Pitched roof single story extension designed by Essex architects, featuring vaulted ceilings, Velux windows, and a traditional finish that blends with the existing home.

Why choose a pitched roof?

If you’re after a solid all-round option when comparing roof extension types, a pitched roof single story extension is hard to beat. It’s one of the cheaper options, goes up quick, and with a vaulted ceiling inside, it feels light and spacious.

Here’s a few reasons why we rate pitched roof single story extension ideas so highly for homeowners planning with experienced architectural designers.

A natural fit for traditional architecture

Pitched roof extensions are a natural fit for traditional-style houses. Their classic shape helps the new space feel like it’s always been part of the home. They’re also often preferred by planning departments, as they help maintain the overall character and style of the neighbourhood.

Strong and weather-resistant roof extension type

Pitched roof single story extension ideas are known for their durability. Their angled design helps water drain off easily, reducing the risk of leaks and long-term damage. As one of the most reliable roof extension types, they hold up well in tough weather conditions and are a popular choice among Essex architects for long-lasting home extensions.

Various roof extension types for single story extensions, including flat, pitched, hipped, and gable designs, created by Essex architects to suit different home styles.

Brighter Spaces with Natural Light

The pitch of the roof makes it easy to add roof windows, which bring loads of natural light into the room. It makes the space feel bigger and brighter, and helps create a nicer place to spend time. It's one of the big plus points of pitched roof single story extension ideas.

Room for Proper Insulation

Pitched roofs have more space to add thicker insulation. This helps keep the warmth in, lowers energy bills, and makes the extension more comfortable all year round. Another reason pitched roof single story extension ideas are a smart choice.

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Homeowner speaking with Essex architects in a free Zoom consultation to get expert advice on single story extension ideas, planning, and design.

Could free planning advice help with your extension project?

If you're considering a Pitched Roof vs Flat Roof Extension and need guidance on submitting your local Planning Application, contact Kirkwood today. We offer a free video consultation via Zoom or Teams with one of our planning experts who can walk you through every step, from understanding local planning requirements and design considerations for your extension to budgeting and documentation. Take the first step towards a smoother planning application and a successful home extension with a friendly video call.

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