A bright kitchen opening onto the garden. A cosy family room or a peaceful home office. A single storey extension can completely transform how your home feels - without the cost or stress of moving. With the average cost in the UK around £35,000, it’s an accessible option for many homeowners. But like any big decision, there are pros and cons. This guide breaks down the benefits, challenges, and real-life examples so you can decide if a single storey extension is right for your home.

Beyond adding space, a well-designed extension can enhance the way a home functions, improving natural light, layout, and overall comfort. It’s an opportunity to create a home that better suits changing needs, whether that’s a growing family, more entertaining space, or a quiet retreat. But with any major renovation, there are trade-offs to consider—cost, impact on outdoor space, and potential planning restrictions all play a role.

Understanding both the benefits and the challenges of a single storey extension is key to making the right decision for your home.

What Is a Single Storey Extension?

A single storey extension is an additional structure added to the ground floor of a home, extending outwards to create more living space. These extensions are commonly built at the rear or side of a property, offering homeowners the flexibility to expand their kitchens, create open-plan living areas, or add a new room altogether.

Unlike double storey extensions, single storey additions keep everything on one level, making them particularly appealing for families with young children, older homeowners, or those wanting a smooth indoor-outdoor connection. They can be designed to complement the existing architecture, blending in with the original home or introducing a modern contrast.

While planning permission isn’t always required, factors like size, location, and local regulations must be considered. A well-planned extension can significantly improve how a home functions, but careful thought is needed to ensure it meets both practical and aesthetic needs.

Advantages of Single Storey Extensions

Cost-Effectiveness

A single storey extension is often a more affordable alternative to moving, helping homeowners avoid costs like stamp duty, legal fees, and relocation expenses. It provides valuable extra space without the higher construction costs of a double storey build, which requires additional structural reinforcements. While prices vary based on design and materials, a well-planned extension can offer excellent value for money.

Beyond the initial cost savings, a thoughtfully designed extension can also increase property value, making it a smart long-term investment. Choosing cost-effective materials, optimizing layouts, and carefully managing the budget ensures that the extension enhances both functionality and financial return without unnecessary expenses.

Simplified Planning Permission

One of the biggest advantages of a single storey extension is that it often falls under permitted development rights, meaning homeowners can extend their property without applying for full planning permission. This makes the process quicker and more cost-effective. To qualify, the extension must meet certain criteria, including:

Size limits: The extension must not extend beyond the rear wall of the house by more than six metres (or eight metres for detached houses).
Height restrictions: It must be no taller than four metres and should not exceed the height of the existing house.
Materials: The new structure should use materials similar to the original house to maintain visual harmony.
Location: Extensions cannot be built forward of the principal elevation or near certain boundaries without permission.

While this streamlined approach makes extensions more accessible, there are exceptions, particularly for:

Listed buildings and homes in conservation areas.
Properties that have already been extended under previous planning rules.
Projects that significantly alter the original home’s footprint.

Working with an architect helps ensure compliance with local regulations and avoids unexpected delays. Here at James Williamson Architects, we provide expert guidance, helping homeowners design within permitted development rules to minimize bureaucracy while achieving a high-quality, functional extension.

Enhanced Living Space

A single storey extension does more than just add square footage—it transforms how a home feels and functions. Well-designed extensions improve natural light, create better flow between rooms, and provide a seamless connection to outdoor spaces. Features like large bi-fold or sliding glass doors can make a kitchen extension feel twice as spacious by opening it up to the garden, while skylights or floor-to-ceiling windows flood the space with natural light, reducing reliance on artificial lighting.

Beyond aesthetics, an extension can solve everyday challenges. A growing family might need a larger kitchen-diner for mealtimes, while remote workers benefit from a dedicated home office. Even smaller extensions, such as side return additions, can make narrow spaces more practical and open. Thoughtful design choices ensure that the new space not only looks good but also enhances daily living in meaningful ways.

Disadvantages of Single Storey Extensions

While single storey extensions offer great benefits, they also come with certain drawbacks that homeowners should consider before starting a project. Below are some key challenges and how they might impact your home.

Limited Space Addition – Unlike a double storey extension, a single storey only expands horizontally, which may not provide enough extra room for growing families. Property boundaries and planning constraints can further restrict the available space.
Reduced Outdoor Area – Extending outward means sacrificing part of your garden or patio. For homes with limited outdoor space, this can impact lifestyle, especially for families who value outdoor activities or entertaining.
Structural and Design Challenges – Matching the extension seamlessly to the original home requires careful planning. Foundations, drainage, and roofing must be properly integrated to avoid costly modifications later.
Potential Planning Restrictions – While planning permission is often simpler, certain areas or listed buildings may have restrictions, requiring additional approvals that can delay the project.

Understanding these challenges helps homeowners make informed decisions, ensuring their extension enhances the home without unintended drawbacks.

Case Studies and Examples

Successful Single Storey Extensions

A great example of a well-executed single storey extension is a family home extension in Sussex, completed by James Williamson Architects. The homeowners wanted a larger, brighter space for family life without compromising their garden. The solution was a rear extension with an open-plan kitchen, dining, and living area, featuring large sliding glass doors connecting to the garden.

Carefully selected materials ensured the new space blended with the original home, while a skylight and full-height glazing maximized natural light. This project demonstrates how a single storey extension can enhance everyday living, creating a spacious, modern environment while maintaining outdoor space and respecting the home’s character.

Lessons Learned from Challenges

The project faced several challenges that were carefully addressed to ensure a seamless and high-quality outcome. One major hurdle was preserving natural light while extending the home. The original rear rooms risked becoming dark and enclosed, so the design incorporated large sliding glass doors, skylights, and full-height glazing to bring in as much daylight as possible, creating a bright, airy space.

Another challenge was blending old and new elements without the extension feeling like an afterthought. To overcome this, materials were carefully chosen to complement the existing home, while a continuous ceiling height and matching finishes ensured a cohesive design. The extension now feels like a natural evolution of the house rather than a disconnected addition.

Finally, maintaining garden space was a priority for the homeowners. By using an efficient footprint and prioritizing indoor-outdoor flow, the project achieved a spacious living area without sacrificing valuable outdoor space, demonstrating how thoughtful planning can overcome common extension challenges.

Conclusion

A single storey extension can transform a home, adding space, improving functionality, and enhancing natural light. While challenges like limited space and outdoor impact exist, thoughtful design and expert planning can help overcome them, ensuring the extension feels well-integrated.

With our expertise on single storey extensions, James Williamson Architects can help bring your vision to life with smart, tailored designs that maximise space and efficiency. Call 07738 409199 to discuss your project and start planning your ideal home extension today.

Frequently Asked Questions (FAQs)

1. Do I need planning permission for a single storey extension?

In many cases, single storey extensions fall under permitted development rights, meaning you won’t need full planning permission. However, restrictions apply based on size, height, and location, so it’s always best to check with your local authority.

2. How much does a single storey extension cost?

3. Will a single storey extension add value to my home?

4. How long does it take to build a single storey extension?

5. How can I ensure my extension blends with my existing home?

Is a Single Storey Extension Right for Your Home? Pros, Cons & Expert Advice