Insight
Permitted Development Explained:
Your Questions Answered:

Permitted Development (PD) is often seen as a shortcut through the planning system – but in reality, it can be just as nuanced as a full planning application. With the right advice, it can unlock valuable opportunities for property owners. Get it wrong, however, and it can lead to delays, added costs, or even enforcement action.

In this FAQ-style guide, Geoff Megarity shares practical insights into what permitted development really means, where it works well, and where people often come unstuck.

1. What is Permitted Development?

Permitted Development rights are a set of national rules set out in the General Permitted Development Order (GPDO). They allow certain types of development to take place without the need to apply for full planning permission – provided strict criteria are met.

These rights cover a wide range of development, from home extensions and alterations to changes of use. However, they are far from a “free pass”- they come with detailed limitations and conditions that must be followed precisely.

2. Does Permitted Development apply to every property?

No – and this is one of the biggest misconceptions.

Residential Permitted Development rights:

• Apply only to houses (not flats or maisonettes)
• May be restricted or removed through planning conditions
• Are often limited in conservation areas
• Do not always apply to listed buildings

Local authorities can also remove specific rights in a defined area using an Article 4 Direction, meaning what is allowed in one street may not be allowed in another nearby.

3. What can I build under Permitted Development?

For homeowners, the most common types of development include:

Rear extensions

• Up to 4 metres for detached houses
• Up to 3 metres for semi-detached and terraced houses

Larger extensions (up to 8m or 6m respectively) may be possible through a prior approval process, which involves neighbour consultation.

Loft conversions

• Up to 50 cubic metres (detached)
• Up to 40 cubic metres (semi/terrace)

Outbuildings

• Up to 50% of the garden area
• Must be for incidental use (e.g. home office, gym)

While these sound straightforward, factors such as height, proximity to boundaries, and the “original house” definition can significantly affect what is allowed.

There are also a wide range of Permitted Development rights that apply to non-residential properties with similar complexities.

4. What is “prior approval” and how is it different?

Prior approval sits somewhere between Permitted Development and a full planning application.

It is typically required for:

• Larger home extensions
• Certain changes of use (e.g. agricultural buildings)

The key difference is that:

• The principle of development is accepted
• But specific impacts (such as neighbour amenity and defined technical matters) are assessed

If neighbours or other consultees raise objections, the council may have to assess the proposal more closely, or require a full planning application.

5. What are the common pitfalls?

Permitted Development is often described as simple, but in practice, it rarely is.

Common issues include:

• Misunderstanding what counts as the “original dwelling”
• Overlooking historic planning conditions
• It not being clear from the Council’s website whether rights are restricted
• Exceeding height or volume limits
• Assuming “if my neighbour did it, I can too”

In some cases, resolving these issues requires digging into historic records – even aerial photographs – to establish what existed decades ago.

6. Do I need a Certificate of Lawfulness?

While not legally required, applying for a Certificate of Lawfulness is strongly recommended if you want a formal record that the Council accept the proposals qualify as Permitted Development.

This confirms that your proposal complies with Permitted Development rules and provides:

• Certainty before building begins
• Protection when selling the property
• Evidence if challenged by the local authority

Without it, you carry the risk that your development may later be deemed unlawful.

7. What happens if I get it wrong?

If a development does not comply with Permitted Development rules, it becomes unauthorised development.

This can lead to:

• A planning contravention notice requiring information to be provided on the development
• A request to submit a retrospective application
• In worst cases, enforcement action requiring alteration or removal

This is why early advice is critical – small design changes at the outset can avoid major problems later.

8. When should I choose Permitted Development over planning permission?

Permitted Development is most useful when:

• Your proposal fits within the defined limits
• You want certainty and speed
• You wish to avoid subjective planning policies

However, if your ambitions go beyond those limits, such as larger extensions or more bespoke designs, a full planning application may be more appropriate.

In some cases, Permitted Development can also be used strategically to create a fallback position, strengthening a future planning application for a proposal that might otherwise be unacceptable.

9. Final thoughts: shortcut or risk?

Permitted Development can be both, but initial planning advice can save significant time and expense.

Early input helps:

• Confirm whether Permitted Development rights apply
• Identify constraints or opportunities
• Shape a clear planning strategy

Used correctly, it provides a clear and efficient route to improving your property. Used incorrectly, it can lead to delays, redesigns and additional cost.

The key is understanding that while Permitted Development avoids planning permission, it does not avoid planning complexity.

Getting the right advice early ensures you make the most of the opportunity – while avoiding the pitfalls.