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What is permitted design?

When planning home improvements or small-scale developments in the UK, you may not always need planning permission. Instead, your project might fall under Permitted Development Rights (PDRs)—a set of rules that allow certain types of building work without needing full planning approval. But what exactly qualifies as permitted development, and what are the limitations? This guide breaks it down.

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What is Permitted Development?

Permitted Development Rights are government-granted allowances that enable homeowners and developers to carry out specific building work without applying for planning permission. These rights are designed to simplify the process for minor alterations while ensuring developments still respect local planning policies.

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Common Types of Permitted Development

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1. Home Extensions

Under permitted development, you can build home extensions without needing prior approval, provided the work meets certain conditions. Here are the non-prior approval limits:

  • Single-storey rear extensions: These can extend up to 3 metres from the original rear wall of a terraced or semi-detached house and up to 4 metres from a detached house.

  • Height: For single-storey rear extensions, the height should not exceed 4 metres. For double-storey rear extensions, the extension should not project more than 3 metres from the rear wall of the house.

  • Roof height: The highest part of the roof should not exceed the highest part of the original roof by more than 3 metres.

However, if your extension exceeds the basic size limits or falls outside the conditions, you will need to apply for prior approval from your local council.

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2. Larger Extensions (Prior Approval Required)

For larger extensions, such as those that exceed the non-prior approval limits, prior approval is required. This includes:

  • Up to 8 metres for detached houses: A detached house can extend up to 8 metres beyond the original rear wall, but you must apply for prior approval if the extension is larger than the normal limits.

  • Up to 6 metres for semi-detached and terraced houses: If your house is semi-detached or terraced, you can extend up to 6 metres beyond the rear wall. Like the larger detached extension, prior approval is required for extensions that exceed the standard limits.

The prior approval process involves notifying your local council and allowing them to assess the potential impact on things like the environment, the local area, and neighbouring properties.

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3. Loft Conversions & Roof Alterations

  • You can add up to 40 cubic metres for terraced houses and 50 cubic metres for detached/semi-detached houses.

  • Roof extensions must not extend beyond the plane of the front roof slope if facing a highway.

  • Dormer windows are allowed but must be set back at least 20cm from the roof eaves.

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4. Outbuildings & Garden Structures

  • Sheds, garages, home offices, and other structures can be built if they do not exceed 2.5 metres in height (within 2 metres of a boundary).

  • Outbuildings cannot occupy more than 50% of the land around the original house.

  • No self-contained living accommodation (e.g., a separate dwelling) is allowed under permitted development.

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5. Internal & External Alterations

  • You can reconfigure internal layouts (e.g., removing non-structural walls).

  • Adding or replacing windows and doors is usually permitted, provided they match the character of the property.

  • Installing solar panels is allowed as long as they do not protrude more than 200mm beyond the roof surface.

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6. Change of Use

Certain changes of use are covered under permitted development, including:

  • Office to residential (Class MA) – Converting offices into homes, subject to conditions.

  • Agricultural buildings to residential (Class Q) – Barn conversions into dwellings, with restrictions.

  • Retail to residential (Class M) – Some shops can be converted into homes, depending on location.

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When Does Permitted Development Not Apply?

Not all properties or locations qualify for permitted development rights. You will likely need full planning permission if your property is:

  • In a Conservation Area, National Park, or Area of Outstanding Natural Beauty (AONB).

  • A Listed Building or located in a World Heritage Site.

  • A flat, maisonette, or converted property, as these have different planning regulations.

Additionally, some local councils impose Article 4 Directions, which remove certain permitted development rights—especially in conservation areas or places with strict planning controls.

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Do You Need Prior Approval?

For larger extensions and certain changes of use, you may need to apply for Prior Approval from your local council. This is a streamlined process where the council reviews specific impacts (such as flooding, highways, or noise) before granting approval.

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How to Check if Your Project Qualifies

Before starting work, always:
✅ Check the Planning Portal (www.planningportal.co.uk) for up-to-date guidance.
✅ Consult your local planning authority (LPA) to confirm any additional restrictions in your area.
✅ Consider obtaining a Lawful Development Certificate for extra certainty that your project complies with permitted development rules.

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Final Thoughts

Permitted Development Rights can be a great way to extend or modify your home without the delays of full planning permission. However, restrictions apply, and it is always best to double-check with your local council before starting work.

Need expert advice on your project? Contact Jeffrey Jordan Architects today for professional guidance on planning, design, and permitted development regulations.

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