Do You Need Planning Permission for a Kitchen Extension in London?

If you're planning to extend rather than simply reconfigure your existing kitchen, one of the first questions to answer is whether you'll need planning permission. The rules aren't always intuitive, and they vary depending on your property type, location and the scale of what you're proposing. This guide covers the essentials, though the specifics of your property always need checking with your local council or an architect before work begins.

Permitted development vs full planning permission

Many single-storey rear kitchen extensions in England fall under what's known as permitted development rights, meaning formal planning permission isn't required provided the project stays within specific limits. As a general guide, a single-storey rear extension typically needs to stay under around 4 metres in depth for a detached house, or 3 metres for a semi-detached or terraced house, with height also capped at around 4 metres. Extensions beyond these limits, or anything affecting the front of the property, will usually require a full planning application.

Where the rules get more complicated

A few common situations catch homeowners out:

Conservation areas. Many parts of North London, including areas like Hampstead and Highgate, fall within conservation areas or have Article 4 directions in place. These can remove permitted development rights entirely, meaning even a modest extension may require full planning permission and closer attention to matching materials and architectural character.

Previous extensions. Permitted development allowances are cumulative. If your property has already been extended, the remaining allowance under permitted development may be smaller than you expect, or already used up.

Flats. Permitted development rights generally apply to houses, not flats or maisonettes, so most flat extensions will require a full planning application regardless of scale.

Total footprint limits. Combined with any existing extensions and outbuildings, the total footprint typically cannot exceed a set percentage of your original garden or curtilage, which is easy to overlook when focusing on the new extension in isolation.

What about building regulations?

Planning permission and Building Regulations approval are separate processes. Even an extension that doesn't need planning permission will almost always need Building Regulations sign-off, covering structural work, insulation, drainage, ventilation and fire safety. It's worth discussing both early with whoever is managing your project, since they're often handled by different routes and timelines.

Approval rates vary significantly by borough

If you do need to submit a full planning application, it's worth knowing that outcomes vary considerably across London boroughs, with approval rates for householder extensions ranging widely depending on the local authority and the specific conservation considerations in your area. This is one of the reasons it pays to involve someone familiar with your specific borough's planning department early in the process, rather than assuming a straightforward result.

How this affects your kitchen design

For us, this matters at the very start of a project. Where an extension is part of the plan, we factor planning and building regulations timelines into the overall project schedule from the outset, so the kitchen design itself isn't finalised in isolation from what's actually achievable in your space, or how long the wider approval process is likely to take.

Getting it right from the start

Because planning rules genuinely vary by borough, conservation status and property history, the most reliable first step is always checking your specific situation with your local planning authority, or with an architect or planning consultant who knows your area well. Once you have clarity on what's possible, we can help design a kitchen that makes the most of the space, whatever the final footprint turns out to be.

If you're planning an extension alongside a new kitchen, book a design consultation and we can talk through how the two processes fit together for your project.