Single Story Extensions - More Space, Less Stress

Single story extensions add more space without the hassle of moving. They can transform a home by creating a larger kitchen, open-plan living area, or extra rooms tailored to your needs. 

Types of Single Story-Extensions

Single story extensions come in a variety of styles, each offering different benefits depending on your space and needs. To find out more about the areas we cover, click here.  For single story extensions, some popular options include:

Rear Extensions

Side Extensions

Wraparound Extensions

Flat Roof Extensions

Pitched Roof Extensions

Porch Extensions

Garage Conversions

Outbuildings/Annex

Choosing the right single story extension

Understanding the different types of single story extensions will help you make an informed decision. From rear extensions that open up your home to side extensions that make use of unused space, each option is designed to meet different needs. Some extensions are best suited for large gardens, while others are perfect for homes with limited outdoor space. Below, we explore the various types of single story extensions to help you find the right solution for your home.

Contemporary single story home extension designed by Essex Architects
Modern rear home extension designed by Essex Architects, enhancing outdoor living space

Rear Single-Story Extensions

A rear single story extension provides additional space by extending into the garden, creating an open-plan kitchen, living area, or home office. Before starting, it’s important to have planning permission, building regulations, and party wall matters in place.

 

 

Permitted Development

Many extensions fall under permitted development, with terraced and semi-detached homes allowed up to 3m or up to 6m with prior approval. Detached homes can extend up to 4m under permitted development or up to 8m with prior approval. Larger extensions require full planning permission, and an architect can help streamline the process.

Side Single-Story Extensions

A single story side extension is a great way to utilise unused land, whether to expand a kitchen, create a new living area, or add a utility room. Many homeowners choose to knock down internal walls, opening up the space to form a larger kitchen-dining area or a seamless extension of the existing living room. Others opt for a side infill extension, transforming narrow side spaces into practical areas for dining, entertaining, or everyday use.

Other Options

A side extension can also serve as a utility room, offering extra storage and space for laundry appliances. Maximising natural light is key, with skylights, glass doors, and large windows helping to brighten up the space. Designed well, a side extension not only improves functionality but also adds significant value to a property.

Side extension in Grays, Essex, designed by Kirkwood Architects and built by our expert builders.

Wrap Around Extensions

Wraparound extensions make use of both the side and rear of a property, forming an L-shaped space that maximises the home’s footprint. Often found in period properties with side alleyways, this type of extension transforms underused areas into functional living space. It provides room for larger kitchens, playrooms, or utility areas while improving the connection between indoor and outdoor spaces.

Natural Light

Enhances through clever design, making the home feel more open and spacious. Costs for a 45 sqm wraparound extension typically range from £75,000 to £145,000 in London and £60,000 to £120,000 elsewhere, depending on materials, contractors, and structural work required. Additional expenses such as VAT, glazing, kitchens, and professional fees should also be factored into the budget. With the right planning, a wraparound extension can add significant value to a property while making better use of available space.

A modern wraparound extension in Billericay, Essex, designed by Kirkwood Architects to create a spacious open-plan living area.

Flat Roof Single-Story Extensions

Flat roof single story extensions are a modern and cost-effective way to expand your home. Unlike pitched roofs, flat roof extensions require fewer materials, making them a more affordable option while also being quick to construct. Their sleek, horizontal design allows them to fit into tighter spaces without the need for angled sides, making them ideal for urban homes with limited room to extend.

Low Maintenance & Cost Efficiency

Flat roofs are easy to maintain and require minimal upkeep, with materials like EPDM, felt, and fibreglass providing durable protection. Costs typically range from £50 to £120 per square metre, depending on the material chosen. While flat roof single story extensions generally fall under permitted development, they must meet building regulations, particularly in regard to height restrictions and visibility from public roads.

A contemporary flat roof single story extension in Rayleigh, Essex, designed by Kirkwood Architects.

Pitched Roof Single-Story Extensions

A pitched roof single story extension is a great way to increase space while maintaining a traditional and visually appealing design. Often preferred by planning departments, pitched roofs blend seamlessly with existing homes, making them a popular choice for extensions. They offer improved energy efficiency, as the sloped design allows for better insulation compared to flat roofs. Their shape also enhances durability by preventing water accumulation, reducing the risk of leaks.

Higher Ceilings & Architectural Appeal

A key advantage of pitched roof extensions is the increased ceiling height, which creates a more spacious feel and allows for architectural details such as exposed beams. There are various pitched roof designs, including gable roofs, hipped roofs, and single-slope roofs, each offering unique benefits in terms of aesthetics and structural performance. With the right design, a pitched roof single story extension can enhance both the functionality and character of your home while adding long-term value.

A pitched roof single story kitchen extension in Hornchurch, Essex, designed by Kirkwood Architects for a spacious and light-filled kitchen.

Porch Extensions

A single story porch extension is a simple yet effective way to enhance your home’s entrance, providing extra space for storage while improving curb appeal. Many homeowners choose to add a porch extension to create a sheltered entryway, making it easier to store coats, shoes, and other essentials while offering protection from the elements.

Two Main Options

A porch is also a great addition to single story extensions, helping to create a more defined and practical entrance space. There are two main options: open porches, which provide a decorative feature and a convenient covered area, and enclosed porches, which act as a functional entrance space with added security. Most small porches fall under permitted development, meaning planning permission is not required as long as they remain within size limits. When designed well, a porch extension complements single story extensions, improving both functionality and visual appeal.

A stylish porch extension in Essex, designed by Kirkwood Architects to enhance the home's entrance.

Garage Conversions

A garage conversion is a cost-effective way to increase living space without extending into the garden. Unlike traditional single story extensions, a garage conversion repurposes existing space, making it a quicker and more affordable option for homeowners. Many conversions require minimal structural work, making them ideal for creating an extra bedroom, home office, gym, or even an open-plan kitchen extension.

Approvals & Building Regs

Planning permission is often not required, as most garage conversions fall under permitted development, but building regulations must still be met. When designed well, a garage conversion can blend perfect with single story extensions, improving both the function and value of a home. We offer expert garage conversion design across the whole of Essex, including areas such as Chelmsford, Brentwood, Billericay, Southend, Hornchurch, Grays and Rayleigh.

Garage conversion integrated into single story extension design by Essex Architects

Outbuildings & Annex Extensions

An annex or outbuilding is a versatile home addition that can serve as a great option for single story extensions, from a guest bedroom, home office to a private gym or self-contained living space. Unlike traditional single story extensions, these structures can be either connected to the main house or stand alone.

 

Planning Permission

While planning permission may be required based on size and usage, many annexes still fall under permitted development. When thoughtfully designed, an annex or outbuilding can serve  many purposes and is usually relatively easy to gain permission for.
A modern annex and outbuilding single story extension in Essex, designed by Kirkwood Architects for versatile living space.

Start Your Home Extension the Right Way

A single story extension adds valuable space to your home, but knowing where to start can be confusing. Should you speak to an architect or a builder first? Many turn to design-and-build companies, only to find that architectural work is outsourced and sometimes designed to maximise builder profits—not your home’s potential.

 

Expert Guidance from Day One

At Kirkwood, we’re your first point of contact, ensuring your extension is designed properly, structurally sound, and fully approved before a builder even gets involved. This means no costly surprises, no cutting corners—just a well-planned extension that meets your needs and budget.

Modern kitchen extension and house extension in Colchester, Essex, designed by Kirkwood architects with detailed architectural plans.

Our architectural design work and finished projects in Essex

We've left some good impressions

See what our customers in Essex are saying on

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!
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