Everything You Need To Know About Permitted Development

Can I Build a Rear Extension Under Permitted Development in the UK?

Thinking about extending your home? The good news is that many rear extensions can be built without full planning permission, thanks to permitted development rights. In this guide, we’ll cut through the jargon and share practical tips to help you understand if your rear extension qualifies — and what you need to do to stay compliant.

📝 At a Glance: Key Permitted Development Rules for Rear Extensions

• Single-storey rear extensions can be built without planning permission if they follow certain size and location guidelines.

• Detached homes can extend up to 4 metres to the rear; other houses are limited to 3 metres.

• Two-storey rear extensions can project up to 3 metres from the rear wall.

• A Lawful Development Certificate (LDC) is highly recommended to prove your extension is legal.

• Designated land (e.g. conservation areas, national parks) has stricter rules and often limits what’s allowed.

• While not required, consulting neighbours early on can help avoid disputes later.

Understanding Designated Land Restrictions

“Designated land” refers to protected areas such as:

• National Parks

• Areas of Outstanding Natural Beauty (AONBs)

• Conservation Areas

• The Broads

• World Heritage Sites

• Green Belt land

If your home is located in one of these areas, permitted development rights are more limited. For example:

• Exterior cladding on extensions is typically not allowed.

• Side extensions or combining side and rear extensions are often restricted.

Always check with your local planning authority—rules can vary depending on their level of enforcement.

✅ Permitted Development for Single-Storey Rear Extensions

Single-storey rear extensions are allowed under permitted development if they meet the following criteria:

• Must not extend more than:

  • 4 metres beyond the rear wall of a detached house

  • 3 metres for any other type of house

• Under the Larger Home Extension Scheme (a prior approval process), these limits can increase to:

  • 8 metres (detached homes)

  • 6 metres (others)

• These extended limits do not apply in designated areas.

• You must still comply with overall height, boundary, and material regulations.

💡 Tip: Apply for a Lawful Development Certificate to confirm your build is compliant and protect against future legal challenges.

✅ Permitted Development for Two-Storey Rear Extensions

Two-storey rear extensions can also fall under permitted development, provided they meet more detailed criteria:

• Maximum extension of 3 metres from the original rear wall

• Must be at least 7 metres away from the rear boundary (10m in Scotland, 10.5m in Wales)

• Extension must not exceed the height of the original house

• Roof pitch must match the existing roof as closely as possible

• Eaves height cannot exceed 3 metres if within 2 metres of a boundary

• Upper-floor side windows below 1.7 metres from floor level must be obscure-glazed and non-opening

• No balconies or verandas are allowed under permitted development

🧑‍🤝‍🧑 The Neighbour Consultation Scheme

While most permitted development projects don’t require planning permission or formal neighbour approval, it's wise to keep communication open. The Neighbour Consultation Scheme gives neighbours the chance to raise concerns during the prior approval process—particularly if you’re building a larger rear extension.

This might sound like opening the door to objections, but in reality, being transparent with your neighbours can help prevent conflict. Submitting a prior approval application shows that you’ve considered how your extension may affect them. It also provides a formal paper trail that can protect you down the line.

💡 Pro tip: If you anticipate objections, this process gives you a chance to respond early—rather than face complaints after construction starts.

✅ Apply for a Lawful Development Certificate (LDC)

One of the smartest ways to protect your project is by obtaining a Lawful Development Certificate from your local planning authority. This certificate confirms that your extension is legally permitted under current rules.

Why is this important?

• It proves your build is compliant, offering protection against future planning changes.

• It’s a useful document to have if you ever sell your home, reassuring buyers that your extension was built legally.

• If disputes arise later—whether from neighbours or local authorities—you’ll have official evidence that your project was lawful at the time it was built.

  

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