Kitchen Extension Planning Permission in London: What You Need to Know
Extending your kitchen is one of the most popular home improvement projects in London — and for good reason. A well-executed kitchen extension adds space, light, and genuine value to your property. But before you start making plans, you need to understand the planning rules. Getting this wrong can lead to delays, enforcement action, or expensive remedial work.
This guide breaks down exactly when you need planning permission for a kitchen extension in London, what the Permitted Development rules allow, and the mistakes that homeowners regularly make.
Do You Always Need Planning Permission?
Not always. Many kitchen extensions in London fall under Permitted Development (PD) rights, which allow certain types of work to be carried out without a full planning application — provided they meet specific size and design criteria. However, London has some important complications that make this more nuanced than in other parts of the country.
If your property is in a Conservation Area, a National Park, an Area of Outstanding Natural Beauty, or is a Listed Building, your PD rights will be restricted or removed entirely. Even if none of these apply, some London boroughs have issued Article 4 Directions, which remove PD rights in certain streets or areas. Always check with your local planning authority before assuming you can proceed without permission.
What Does Permitted Development Allow?
For a single-storey rear extension — the most common kitchen extension type — Permitted Development generally permits:
- Extensions up to 3 metres deep for terraced or semi-detached properties
- Extensions up to 4 metres deep for detached houses
- A maximum height of 4 metres (or 3 metres if within 2 metres of a boundary)
- The extension must not cover more than half the area of the original garden
There is also the Larger Home Extension Scheme (sometimes called the Prior Approval route), which allows extensions of up to 6 metres for semi-detached and terraced properties, and up to 8 metres for detached homes. This requires a formal Prior Approval application and a neighbour consultation period, but it is still a lighter-touch process than full planning permission.
When Full Planning Permission Is Required
You will need a full planning application when:
- Your property is in a Conservation Area or is Listed
- The extension exceeds the PD size limits
- You are extending to the side of the property (different rules apply)
- The design uses materials that do not match the existing house
- You are combining a rear and side extension (a wraparound), which typically requires permission
Common Mistakes Homeowners Make
Assuming PD rights apply automatically. Even if your project looks like standard PD work, it is worth getting a Lawful Development Certificate (LDC) from your local council. This certificate confirms your extension is lawful and protects you when you come to sell the property.
Ignoring party wall obligations. If your extension involves work near or on a shared boundary, you may have obligations under the Party Wall Act 1996, regardless of whether planning permission is needed. Failing to serve the correct notices can cause significant disputes with neighbours.
Not checking for an Article 4 Direction. In many parts of London, Article 4 Directions have been applied to residential streets, removing standard PD rights. A quick check with your borough council before committing to a design could save you a costly rethink.
Conflating planning permission with Building Regulations approval. Even where no planning permission is needed, almost all kitchen extensions require Building Regulations approval. These are separate processes covering structural safety, fire safety, energy efficiency, and drainage. One does not replace the other.
Choosing a contractor before resolving the planning position. The sequence matters. Committing to a contractor and starting work before planning is confirmed is a significant risk. A good design-and-build principal contractor will help you establish the planning position as part of the early project process — not as an afterthought.
Working with a Principal Contractor
Navigating planning rules in London requires experience. A reputable principal contractor with a track record of London extensions will understand the local planning landscape, help you identify whether your project needs Prior Approval or full permission, and coordinate with architects and consultants to get your project moving on the right footing.
At RCB Design & Build, we work with homeowners across Greater London to take kitchen extensions from initial idea through planning, design, and full delivery — making sure every step is properly managed and documented.
Ready to start planning your kitchen extension? Contact RCB Design & Build today for a structured initial conversation about your project.
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