Most homeowners planning a kitchen extension assume the first step is a planning application. Usually it isn't. The government has already granted planning permission for a whole class of single-storey rear extensions through something called permitted development, and a typical kitchen extension sits squarely inside it. The real question is whether yours does.
This article covers England. Wales, Scotland and Northern Ireland run their own planning systems with different limits and fees (Wales, for example, allows 6m for all house types under its own prior-approval scheme, and Scotland's standard allowance is 4m regardless of house type). If you're outside England, check your national guidance before relying on any figure below.
So the answer is yes, no, or it depends, and the thing it depends on is a measurable test. Here it is.
The Permitted Development Test for a Kitchen Extension
Permitted development (PD) rights come from the Town and Country Planning (General Permitted Development) (England) Order 2015. They are a blanket planning permission granted by Government, not by your council. If your extension meets every condition, you can build without applying for planning permission at all.
For a single-storey rear kitchen extension in England, the limits that matter are:
| Limit | Semi-detached or terraced | Detached |
|---|---|---|
| Rear extension depth (standard PD) | 3m beyond the original rear wall | 4m beyond the original rear wall |
| Rear extension depth (with prior approval) | Up to 6m | Up to 8m |
| Maximum overall height | 4m | 4m |
| Maximum eaves height within 2m of a boundary | 3m | 3m |
| Garden coverage (all extensions and outbuildings combined) | No more than 50% of the land around the original house | Same |
Two of those rows trip people up more than any others.
First, depth is measured from the original rear wall. That means the house as it was first built, or as it stood on 1 July 1948 if it's older than that. A previous owner's extension counts against your allowance even though you never built it. If your Victorian terrace already has a rear outrigger housing the kitchen, your 3m may already be partly or fully spent.
Second, the 50% rule counts everything cumulatively. The garden shed, the previous owner's conservatory, the garage: all of it eats into the half of the original garden you're allowed to cover.
There are also conditions on appearance and position. Materials must be similar in appearance to the existing house. And side extensions have their own rules: single storey only, no wider than half the width of the original house, and no PD at all for side extensions on designated land. This matters for kitchens specifically, because a lot of kitchen extensions on older terraces are wrap-arounds that fill the gap beside a rear outrigger. A wrap-around is a rear extension and a side extension at the same time, and it has to pass both tests. Plenty fail the side test while sailing through the rear one.
The full set of conditions, with worked examples for awkward house shapes, is in the tree's permitted development rules leaf. One reassuring note before you measure anything: these limits have been stable for years. A 2024 government consultation proposed loosening them, but nothing has been implemented as of mid-2026, so the figures above are the ones in force.
The 6-Metre Rule: Prior Approval for Larger Extensions
Between permitted development and full planning permission sits a third route most homeowners have never heard of: the Larger Home Extension scheme, usually shorthanded as the 6-metre rule.
If your single-storey rear extension goes beyond the standard 3m (or 4m detached) but stays within 6m (8m detached), you can use the prior approval process instead of a full planning application. You notify the council before starting work, the council writes to your adjoining neighbours, and the neighbours get 21 days to object. If nobody objects, the council has 42 days in total to respond, and silence counts as approval. If a neighbour does object, the council assesses the impact on their amenity and decides.
Prior approval is faster and cheaper than a full application (the council fee is £249, plus a service charge of around £91 if you submit through the Planning Portal; check the Planning Portal for the current figures). But be clear about what it is. Prior approval is a notification-and-consent process within permitted development. It is a lighter-touch check than full planning permission, and starting the build before the process completes puts you at risk of enforcement even if the extension would have qualified. Real neighbour disputes have started exactly that way.
The mechanics, timings and drawings you need are covered in the prior approval for larger home extensions leaf.
When Permitted Development Does Not Apply
PD rights are generous, but several situations switch them off entirely or cut them back hard:
- Flats and maisonettes. No householder PD rights at all. A ground-floor flat kitchen extension always needs a planning application.
- Listed buildings. You'll need listed building consent on top of planning considerations. Assume nothing is permitted until confirmed.
- Conservation areas, National Parks, Areas of Outstanding Natural Beauty, the Broads, World Heritage Sites. This is "Article 2(3) designated land". Side extensions lose PD rights, rear extensions of more than one storey lose them, and the 6m/8m Larger Home Extension scheme is not available at all.
- Article 4 directions. Councils can remove specific PD rights across an area, most commonly in conservation areas. Islington, for one, has removed PD rights in 40 of its 42 conservation areas.
- Houses created through PD conversion. If your home was converted from an office or agricultural building under PD, it usually has no householder PD rights for further extension.
Warning
Planning Permission and Building Regulations Are Two Different Systems
Here's the distinction competitor guides regularly blur: planning permission and building regulations approval are separate systems, run by separate teams, with separate applications, fees, timelines and reference numbers. Passing one gets you nothing with the other.
Planning is about whether the extension should exist at all: its size, its position, its effect on neighbours and the street. Building regulations are about whether it's built safely: foundations, structure, insulation, drainage, ventilation, electrics.
A kitchen extension built under permitted development skips the planning application. It never skips building regulations. You (or your builder) still submit a building control application, still get inspected at set stages, and still need a completion certificate at the end. On a real 30m² kitchen extension in Oxfordshire, planning permission was granted in May 2021 and the building control application followed as a completely separate submission weeks later, with its own fee and its own reference. Two systems, two processes, and the second one applies to every extension regardless of how the first was resolved.
The Lawful Development Certificate: Get One Even If You Don't Need Permission
If your kitchen extension qualifies as permitted development, nothing forces you to tell the council anything before building. Skipping that paperwork entirely is a mistake.
A Lawful Development Certificate (LDC) is the council's formal confirmation that your extension is lawful. It isn't planning permission and it isn't discretionary: if the facts fit the rules, the council must issue it, and neighbours have no right to object. The fee in England is £274, half the cost of a householder planning application (check the Planning Portal for the current fee).
What you're buying is proof. When you sell, the buyer's solicitor will ask what authorised the extension, and "we measured it ourselves and decided it was fine" goes down badly with conveyancers and mortgage lenders. An LDC answers the question in one document. It also locks in your position: unlike planning permission, it never expires, and it protects a not-yet-built scheme if the council later brings in an Article 4 direction that would have removed your PD rights.
Tip
What a Real Kitchen Extension Did, and Why
A real 30m² rear kitchen extension in Oxfordshire went the full householder planning application route: application submitted in late March 2021, council site visit in mid-May, permission granted 24 May 2021. Roughly eight weeks, which matched the statutory target. Treat that as the floor rather than the norm: realistic determination times in 2026 run 12-16 weeks in much of England.
Why full planning rather than PD? The extension's depth was beyond the comfortable standard PD envelope, and the project bundled in roofline changes and a full rear reconfiguration that made self-certifying against the PD conditions a risk rather than a shortcut. A full application banked an approved drawing set with the council before a single trench was dug. That's the same certainty an LDC buys for a PD scheme, purchased a different way. The lesson transfers: whichever route you take, get the council's position in writing before work starts. Marginal cases argued after the build are the expensive kind.
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Your Next Step
The decision comes down to a short sequence:
- Check the disqualifiers first. Flat, listed building, conservation area or other designated land, Article 4 direction, or PD rights removed by an old planning condition? You're applying for planning permission. Start with submitting a planning application.
- Measure against the original house. Comfortably within 3m (attached) or 4m (detached), under the height and eaves limits, under 50% garden coverage? You're likely in permitted development. Confirm it properly with the checks in do you need planning permission, then apply for an LDC.
- Between 3-6m (or 4-8m detached)? Use the prior approval route and wait for the outcome before starting.
- Marginal or complicated? A one-off conversation with your council's pre-application service, or an hour of a planning consultant's time, is cheap against the cost of an enforcement notice ordering you to undo the work.
Permission is only the first gate. The kitchen extension tree maps every task from this decision through to the completion certificate, in build order, and the structure is free to browse: see the full kitchen extension tree. The Access Pass (£49) opens the working detail on every task, including the application walkthroughs, fee checklists and council correspondence templates for this phase. Later posts in this Getting Permission series pick up what happens after this decision, including the application itself and dealing with neighbours.
Frequently Asked Questions
How big can I build a kitchen extension without planning permission?
Under standard permitted development in England: 3m beyond the original rear wall for a semi-detached or terraced house, 4m for a detached house, with a maximum height of 4m and eaves no higher than 3m within 2m of a boundary. All extensions and outbuildings combined must cover no more than half the land around the original house. Go beyond the depth limits and you'll need prior approval (up to 6m/8m) or full planning permission.
What is the 6-metre rule for extensions?
It's the Larger Home Extension scheme. Semi-detached and terraced houses can extend 3-6m from the original rear wall, and detached houses 4-8m, without full planning permission, provided the council grants prior approval first. The council consults your neighbours for 21 days and has 42 days to decide. It's a lighter process than a planning application, but it isn't automatic and it isn't available on designated land.
Does living in a conservation area change things?
Substantially. Conservation areas are designated land, so side extensions and multi-storey rear extensions lose permitted development rights, and the 6m/8m prior approval route disappears entirely. A modest single-storey rear kitchen extension can still qualify under standard PD limits, but many councils also apply Article 4 directions in conservation areas that remove those remaining rights too. Check both the designation and any Article 4 direction with your council before assuming anything.
What if my permitted development rights were removed?
Then every extension needs a planning application, however small. Rights get removed two ways: a condition attached to a previous planning permission for your specific property (which binds all future owners), or an Article 4 direction covering your area. Neither shows up on a viewing or a mortgage survey, so search the council's planning register for your address and read the conditions on every past permission before you spend money on design work.