Permitted development: what you can build without planning permission

Not every home improvement needs planning permission. A large share of extensions, loft conversions and garden buildings in England are built under permitted development (PD) rights, which are national rules that let you carry out certain work without applying to your council at all.

The catch is that PD is far more detailed than most people expect. The rights come with precise limits on size, height and position, and they are switched off entirely for some properties and some areas. Get it wrong and the consequences are real: an enforcement notice, an order to undo the work, and a problem that surfaces years later when you try to sell.

This guide explains what you can build without planning permission, the exact limits that apply, and the rules that most often catch people out.

First: check that permitted development even applies to your home

Before any of the size limits matter, four things can remove your PD rights completely. If any of these apply, assume you will need a planning application regardless of how modest your project is.

1. You live in a flat or maisonette. Householder permitted development rights apply to houses, not flats. If you own a flat, virtually any external alteration needs permission. This surprises a lot of people.
2. Your property is listed. Listed buildings have heavily restricted PD rights, and most external (and many internal) changes need listed building consent as well as planning permission, which are two separate applications. Carrying out work to a listed building without consent is a criminal offence, not just a planning matter, so this is one to take seriously.
3. You are on "designated land". Conservation areas, National Parks, the Broads, National Landscapes (formerly Areas of Outstanding Natural Beauty) and World Heritage Sites all have reduced PD rights. Side extensions, roof extensions and the larger rear-extension scheme generally do not apply, and outbuildings are more limited.
4. Your rights have been removed by an Article 4 direction or a planning condition. Councils can issue an Article 4 direction that strips out specified PD rights across a defined area, sometimes a single street, sometimes a whole borough. And if your house was built or extended under a recent planning permission, that permission may have removed future PD rights by condition, which is very common on newer estates. Neither is visible from the street.

This last point is the honest limit of any general guide. We can tell you what the rules are. We cannot tell you whether they have been switched off at your specific address, because an Article 4 direction or a removed-PD condition only shows up when you check the records for that property. That property-specific check is exactly what a Planiverse property report does. The rest of this guide assumes your PD rights are intact.

The concept that underpins every limit: the "original house"

Almost every PD allowance is measured against your original house, meaning the house as it stood on 1 July 1948, or as it was first built if later. It is not measured against the house as it is today.

This matters because any extension a previous owner added counts against your allowance. If the house was extended to the rear before you bought it, you may have little or no PD headroom left, even though you have not built anything. Always work out what is already been added before you assume you can extend.

A second running limit: extensions and outbuildings together must not cover more than 50% of the land around the original house (the "curtilage", which is your plot, excluding the footprint of the original house itself).

What you can build under permitted development

Single-storey rear extension

The most common PD project. A single-storey rear extension is permitted development if it stays within these limits:

• Depth from the original rear wall: up to 3m for an attached house (terraced or semi-detached), or 4m for a detached house.
• Height: no more than 4m overall.
• Eaves: no higher than 3m if it is within 2m of a boundary.
• Materials similar in appearance to the existing house.

Going deeper, the "Larger Home Extension" route. You can extend further, up to 6m (attached) or 8m (detached), but only through the prior approval process, where the council notifies your neighbours and gives them a chance to object on grounds of impact. This scheme does not apply on designated land. More on prior approval below.

Two-storey rear extension

Permitted, but tightly constrained:

• No more than 3m beyond the original rear wall.
• At least 7m from the rear boundary.
• Roof pitch to match the existing house where practical.
• Upper-floor side windows obscure-glazed and non-opening below 1.7m.
• Not permitted on designated land.

Side extension

• Single storey only, maximum 4m high.
• No wider than half the width of the original house.
• Not permitted on designated land. Side extensions in conservation areas and National Parks need planning permission.

Loft conversion and roof additions

• Volume allowance of up to 40 cubic metres for terraced houses, or 50 cubic metres for detached and semi-detached houses (this includes any earlier roof additions).
• No higher than the highest part of the existing roof.
• No extension beyond the roof plane on the side facing a highway, which is why front-facing dormers almost always need planning permission, while rear dormers often do not.
• Materials similar in appearance; side-facing windows obscure-glazed.
• Not permitted on designated land. Roof extensions in conservation areas and National Parks need permission.

Simple rooflights or skylights that sit close to the roof slope (projecting no more than 150mm and not above the ridge) are generally permitted even where a dormer would not be.

Outbuildings: garden rooms, home offices, sheds, garages

• Single storey, maximum eaves height 2.5m, and maximum overall height 4m (dual-pitched roof) or 3m (any other roof).
• If it is within 2m of a boundary, the maximum overall height drops to 2.5m.
• Must be to the rear of the house. Nothing forward of the principal elevation.
• Must be incidental to the enjoyment of the house. A home office, gym or store is fine; a self-contained living space someone could sleep and live in independently (a "granny annexe") is not, and needs permission.
• Counts toward the 50% curtilage limit.
• On designated land, outbuildings are far more limited (and not permitted at the side of the house).

Porches

A small front porch is permitted if it has a footprint of no more than 3 square metres, is no more than 3m high, and is at least 2m from any boundary fronting a highway.

Windows, doors and minor alterations

Like-for-like replacement windows and doors are generally permitted in most areas, but not where an Article 4 direction or conservation-area status applies, which is one of the most common Article 4 restrictions of all.

The limits that catch most people out

These are the mistakes that turn a "no permission needed" project into an enforcement problem.

1. Front extensions are not permitted development. Anything forward of the principal elevation that fronts a highway needs planning permission (porches aside). PD is essentially a rear-and-side right.
2. Your allowance may already be used up. Because limits are measured against the original house, a previous owner's extension eats into what you can build. Check the planning history before you design anything.
3. Flats get nothing. Householder PD rights do not apply to flats or maisonettes at all.
4. "Matching materials" is enforceable. An extension that is within every size limit can still attract an enforcement complaint if the materials visually jar with the existing house.
5. Designated land changes the rules. In a conservation area, National Park or National Landscape, side extensions, roof extensions and the larger 6m/8m rear scheme drop away, and outbuildings shrink.
6. Article 4 and conditions are invisible. A council can remove PD rights across your area, and a past permission can remove them on your specific house. Neither is obvious from looking at the property.
7. Permitted development is not the same as Building Regulations. PD only means you do not need planning permission. You almost certainly still need Building Regulations approval for the construction itself, covering structure, fire safety, insulation and drainage. They are entirely separate processes.
8. England's rules are not the UK's rules. The 6m/8m larger scheme, for instance, does not exist in Wales. Make sure any guidance you rely on is England-specific.

Prior approval: the in-between route

For larger single-storey rear extensions (the 6m/8m route), you do not need full planning permission, but you do need to go through prior approval, sometimes called the neighbour consultation scheme. You notify the council, which tells your immediate neighbours and gives them a window to object. If a neighbour objects, the council assesses the impact on amenity and decides. If no one objects, you are clear to build.

It is lighter-touch than a full application and a fee applies (lower than a full householder application; check the Planning Portal for the current figure). It is a popular route for big open-plan kitchen extensions that push beyond the standard depth.

Proving it: the Lawful Development Certificate

Permitted development means you can build without applying, but it does not give you a piece of paper saying so. That is what a Lawful Development Certificate (LDC) is for.

An LDC is a formal confirmation from your council that your project is (or was) lawful permitted development. It currently costs £272, and while it is not compulsory, it is genuinely useful:

• It removes the risk that you have misjudged a limit before you spend money building.
• It is the document a buyer's solicitor will ask for when you sell. "It was permitted development, trust me" is not something a conveyancer accepts, and a missing LDC can stall or complicate a sale.

For anything beyond the most obviously trivial, an LDC is cheap insurance.

Are the rules about to change?

In early 2024 the government consulted on expanding householder PD rights, including an additional storey, larger extensions and more relaxed rules on materials. As of 2026, none of that has been brought into law. The consultation is still listed as under analysis, and the current rules described in this guide remain in force. We will update this page if that changes.

Frequently asked questions

In short

Permitted development is generous. Most rear extensions, loft conversions and garden rooms in England can be built without a planning application. But the limits are precise, they are measured against your original house, and they can be switched off entirely by your property type, your location, or rights that were quietly removed years ago.

The general rules in this guide apply to most homes. The one thing they cannot tell you is what is true for your address: whether an Article 4 direction, a conservation area, a listed status or an old planning condition has removed the rights you are counting on, and what your council has actually approved or refused for projects like yours nearby. If you are planning work, that is worth checking before you spend money on drawings.

Related guides

• Article 4 directions — where your council has removed permitted development rights.
• Do I need planning permission? — when permission is required, and when it isn't.
• The planning and build process — what to expect from first idea to finished work.
• Planning permission costs — application, professional and building costs, with current figures.
• Building regulations — how a project is signed off as safe, and the certificate you'll need when you sell.