The short answer
Permitted development is a set of national rights that let you carry out certain projects on a house without a full planning application, as long as you stay within published limits and conditions. The headline rules cover things like single-storey rear extensions — currently up to around three metres beyond the rear wall for a terraced or semi, and four metres for a detached house — and larger extensions are possible under the prior approval route, where the council notifies neighbours before allowing it. Permitted development is generally cheaper and faster than a full application, but it is also more restrictive: it does not apply to flats, is reduced on designated land, and exceeding any limit means you need full permission. It is a trade-off between speed and freedom of design.
Permitted development is the fast lane, but it comes with strict boundaries. Knowing the main limits — and where they stop — helps you decide whether to design within them or apply for full permission.
The headline limits
- Rear extension (terrace/semi)~3 m beyond rear wall
- Rear extension (detached)~4 m beyond rear wall
- Larger scheme routeprior approval (neighbours notified)
- Applies tohouses, not flats
- Designated landrights reduced
How permitted development works
Permitted development rights are granted nationally rather than by your council, so if your project meets every limit and condition you can proceed without a planning application. For single-storey rear extensions the standard limits are about three metres beyond the original rear wall for a terraced or semi-detached house, and four metres for a detached house, with height limits too. Bigger single-storey rear extensions — up to roughly six metres (other houses) or eight metres (detached) — are allowed under the larger home extension prior approval scheme, where the council notifies adjoining owners and rules on amenity. The rights apply to houses only and are cut back on designated land.
| Project | Standard PD limit | With prior approval |
|---|---|---|
| Rear extension (terrace/semi) | ~3 m | up to ~6 m |
| Rear extension (detached) | ~4 m | up to ~8 m |
| Single-storey height | ~4 m max | — |
| Designated land | rights reduced | may need full permission |
Indicative limits for general information — confirm yours with the local authority. Source: Planning Portal technical guidance.
Permitted development vs a full application
- Speed: permitted development avoids the full 8-week determination, though prior approval still involves the council.
- Cost: it usually works out lower in cost, as you may only need a lawful development certificate rather than a full fee.
- Freedom: a full application lets you go beyond the size limits and design more freely, at the price of time and fee.
- Certainty: a full permission or a lawful development certificate both give documented proof, which helps when you sell.
Want to design within permitted development?
We'll match you with a vetted planning consultant who checks the limits for your property and tells you whether your project fits permitted development or needs a full application.
Frequently asked questions
What can I build without planning permission?
On a house, permitted development typically allows many single-storey rear extensions within the size limits (around three metres for a terrace or semi, four metres for a detached home), certain loft conversions, porches and fences within set sizes, and internal alterations. The rights do not apply to flats and are reduced on designated land.
What is prior approval for a larger extension?
It is a route that allows bigger single-storey rear extensions — up to around six metres for most houses or eight metres for a detached home — provided you notify the council first. The council tells adjoining owners, and if they object it decides whether the impact on amenity is acceptable.
Is permitted development always cheaper than a full application?
It usually works out lower in cost because you may avoid the full planning fee and only need a lawful development certificate. But it is more restrictive on size and design, so a full application can still be the better choice for a larger project.
Sources & further reading
- Planning Portal — extensions: planning permission
- GOV.UK — permitted development rights for householders technical guidance
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.