The short answer
Many home improvements do not need planning permission because they are covered by permitted development rights — for example many single-storey rear extensions, loft conversions within limits, and minor alterations. You generally do need permission when a project goes beyond those size and height limits, when you are creating a new dwelling, or when you significantly change the use of a building. The rules tighten for flats and maisonettes (which have no permitted development rights for extensions), listed buildings (which usually need listed building consent), and conservation areas, national parks and AONBs. If you are unsure, you can apply for a lawful development certificate to confirm your project is permitted development. This is general information — always confirm your own case with your local planning authority.
The honest starting point is that a lot of home projects do not need permission at all. The job is working out which side of the line yours falls on — and the limits and exceptions below are where it usually turns.
When permission is usually needed
- Within PD limitsusually no permission
- Beyond size / height limitspermission usually needed
- New dwelling / change of usepermission needed
- Flat or maisonettepermission needed for extensions
- Listed buildinglisted building consent usual
When you usually do not need permission
Permitted development rights let you carry out many projects without a full application, provided you stay within the published limits and conditions. Typical examples for houses include many single-storey rear extensions, certain loft conversions, internal alterations, and minor works like fences and porches within set sizes. These rights apply to houses, not flats or maisonettes, and they are reduced on designated land such as conservation areas. The permitted development page explains the limits in detail.
When you usually do need permission
You generally need to apply when a project exceeds the permitted development limits — for example a rear extension longer or taller than allowed — or when you are creating a new home, sub-dividing a property, or changing how a building is used. The rules are stricter for listed buildings, where external and often internal alterations need listed building consent, and in conservation areas, national parks and AONBs, where permitted development is curtailed. If in doubt, a lawful development certificate gives a formal confirmation that your project is lawful without permission.
| Situation | Permission needed? |
|---|---|
| Project within PD limits (house) | No (permitted development) |
| Project beyond PD limits | Yes (usually) |
| New dwelling or change of use | Yes |
| Extension to a flat or maisonette | Yes |
| Listed building alteration | Yes — listed building consent (usual) |
General guidance — confirm your own case with your local planning authority. Source: Planning Portal.
Not sure if you need permission?
We'll match you with a vetted planning consultant who reviews your project against the permitted development rules and tells you honestly whether you need to apply.
Frequently asked questions
Do I need planning permission for an extension?
Many single-storey rear extensions on houses are covered by permitted development if they stay within the size and height limits. You usually need permission when the extension goes beyond those limits, for any extension to a flat, or on a listed building or designated land. Confirm your case with your local planning authority.
How do I know if my project is permitted development?
Compare it against the published permitted development limits for your project type, and remember the rights apply to houses and are reduced on designated land. If you want certainty, you can apply for a lawful development certificate to confirm the project is lawful without permission.
Do listed buildings and flats follow different rules?
Yes. Flats and maisonettes have no permitted development rights for extensions, so they need permission. Listed buildings usually need listed building consent for alterations, and conservation areas, national parks and AONBs have tighter rules — always check locally.
Sources & further reading
Figures on this page are typical UK ranges drawn from published sources and depend on your specific project. They are general information, not a quotation or planning advice.