At KT5 Construction—your trusted local builders covering Surrey and London—we’re often asked: “Is a 3m extension big enough?” It’s a fair question. With the rising cost of moving and limited outdoor space in London homes, homeowners are eager to maximise their properties without overspending.

A 3-metre extension may sound small on paper, but it can deliver a big impact when designed with care and built by experienced professionals. In this comprehensive guide, we’ll explore whether a 3m extension is right for your home, what it can achieve, and how to ensure it adds value to your lifestyle and your property.

What Does a 3-Metre Extension Provide?

A Smart Space Expansion

A 3-metre extension typically adds around 10–15 square metres of ground floor space. It might seem limited compared to a double-storey addition, but when well-planned, this size is ideal for:

• • An open-plan kitchen and dining area

  • A dedicated home office or playroom

  • A utility space to declutter your main kitchen

  • A cosy living room or snug

This type of extension works particularly well in Victorian and Edwardian terraced or semi-detached propertieswhere garden space is tight, and full planning permission isn’t always required.

Is It Big Enough for Everyday Living?

Yes—If Designed Properly

Functionality doesn’t come from size alone. At KT5 Construction, we use clever design techniques to make every metre count:

• • Bi-fold or sliding doors connect the interior to your garden, enhancing flow.

  • Skylights or roof lanterns make rooms feel bigger and brighter.

  • Open-plan layouts reduce walls and create a seamless experience.

  • Built-in storage and zoning solutions keep the area efficient and clutter-free.

Whether you’re cooking, relaxing, or entertaining, a 3-metre extension can support your lifestyle—without overwhelming your home or garden.

Planning Rules: Do You Need Permission for a 3m Extension?

In most cases, no planning permission is needed for a single-storey rear extension of up to 3 metres on a semi-detached or terraced home. This falls under Permitted Development (PD) rights. Detached homes can extend up to 4 metres without formal planning.

However, exceptions apply:

• • Homes in conservation areas or listed buildings may not qualify.

  • You must use materials similar to the existing structure.

  • The extension cannot exceed height restrictions or cover more than 50% of your garden.

At KT5, we handle all legal aspects—from checking PD eligibility to obtaining Lawful Development Certificates, giving you peace of mind before a single brick is laid.

How Much Does a 3-Metre Extension Cost?

The cost of a 3-metre extension depends on:

• • Location (London and urban boroughs tend to be pricier)

  • Ground conditions and foundation depth

  • Design complexity (open-plan vs partitioned)

  • Structural changes (e.g., removing walls, steel supports)

On average, expect:

• • £1,800 – £2,500 per m² for standard finishes

  • £3,000+ per m² for high-end materials and bespoke features

We always recommend including a 10–15% contingency in your budget. At KT5 Construction, we value-engineer your project to ensure costs stay within your comfort zone, without sacrificing quality.

Why Choose KT5 Construction for Your 3m Extension?

• • 👷 Experienced London builders with a portfolio of 3m extensions across Fulham, Surbiton, Ashford & beyond.

  • 📐 Full service: design, planning, build, and aftercare.

  • 💬 Transparent communication with weekly updates and a dedicated project manager.

  • 💰 Cost-efficient construction with no hidden extras.

  • 🧾 Help with lawful development paperwork for future-proof compliance.

KT5 Construction is the go-to builder for homeowners seeking affordable, stylish extensions—delivered on time and on budget.

Creative Ideas for Your 3m Extension

Wondering how to make the most of your space? Here are some homeowner favourites:

1. The Entertainer’s Kitchen

Extend your existing kitchen and incorporate a dining space with views to the garden. Ideal for sociable households.

2. Dedicated Work-from-Home Zone

Create a sound-insulated office at the rear with natural light, built-in storage, and direct access to the garden.

3. Utility and Laundry Space

Take noisy appliances out of your main kitchen. A separate utility room adds value and function.

4. Playroom or Snug

Give kids their own space or design a reading nook with built-in shelves and ambient lighting.

A well-designed 3m extension offers flexibility, whether your needs evolve with a growing family or hybrid working.

Materials, Light & Finish: Making It Feel Bigger

Your finish matters. Here’s how to make a small extension feel spacious:

• • Use matching bricks for continuity or go bold with render and timber cladding for contrast.

  • Add roof glazing to flood the interior with light.

  • Incorporate continuous flooring from the old to new space to avoid visual breaks.

  • Keep the colour palette light and minimal to maintain openness.

Our KT5 design team helps you visualise your extension before building begins—ensuring a result that fits both your budget and your vision.

Frequently Asked Questions – Is a 3m extension big enough ?

1. Is a 3m extension worth it?

Yes! It increases living space, boosts property value, and is often achievable without full planning.

2. Will a 3m extension fit a dining table?

Absolutely. A typical 3m rear extension can accommodate a table, island, and circulation space—perfect for modern family life.

3. Can I extend more than 3 metres?

Yes, but you’ll likely need to apply under the Larger Home Extension Scheme. We can advise based on your property.

Ready to Plan Your 3-Metre Extension?

Your home has more potential than you think. With KT5 Construction by your side, you can unlock it—creatively, legally, and affordably.

👉 [Email Us Your Requirements Now]
👉 [Book a Consultation with Our Expert Team]