If you've looked into extending or altering your home, you've probably come across the phrase "permitted development" — usually in a sentence like "you might not need planning permission." It's one of the most useful and most misunderstood parts of the planning system.
This guide explains what permitted development rights actually are, what they cover, who they don't apply to, and how to get proof before you build. It covers houses in England; other UK nations have their own rules.
What permitted development is
Normally, building work needs planning permission from your local council. Permitted development (PD) rights are a national grant of permission for certain types of small-scale work, set out in legislation (the General Permitted Development Order). If your project fits within the limits, the permission already exists — you don't need to apply for it.
The key phrase is fits within the limits. PD isn't "anything small is fine." Each type of work has specific, measurable conditions, and you need to meet all of them.
What PD rights typically cover for a house
For a typical house, the main categories are:
- Extensions — single-storey rear extensions, some side extensions, and limited two-storey rear extensions
- Loft conversions — including rear dormers, within volume limits
- Other roof alterations — such as rooflights
- Porches — within size limits
- Outbuildings — garden rooms, sheds and similar, within height and coverage limits
- Hard surfaces — such as driveways, with drainage conditions
For extensions specifically, the headline numbers are 3 metres (attached or semi-detached) or 4 metres (detached) for a single-storey rear extension, with a larger 6 or 8 metre option via prior approval. We go through those in detail in Do You Need Planning Permission for a Rear Extension?
Who doesn't have permitted development rights
This is where most surprises come from. PD rights for houses don't apply to:
- Flats and maisonettes
- Houses created through a change of use — for instance, a former office or agricultural building converted to a home under permitted development
- Properties where rights have been removed, either by an Article 4 direction (a local authority removing specific rights in a defined area) or by a planning condition attached to the original permission. Newer housing estates frequently have conditions like this.
And in conservation areas, National Parks, Areas of Outstanding Natural Beauty, the Broads and World Heritage Sites, PD rights still exist but are cut back — for example, no side extensions, no cladding, and no two-storey rear extensions without planning permission. (See What Is a Conservation Area and How Does It Affect Your Extension?)
Listed buildings are a separate matter entirely — listed building consent is needed for most alterations whatever PD would otherwise allow.
The "original house" rule
PD limits are measured against the original house — the house as it was first built, or as it stood on 1 July 1948 if it was built earlier. Any extension already added, whether by you or a previous owner, uses up part of your allowance.
This is why "my neighbour built a 4-metre extension without permission" tells you very little. They may have had different rights, a different original footprint, or built before the current rules applied.
Prior approval: the in-between option
Some PD rights come with a catch: you must apply for prior approval before building. The best-known example is the larger home extension scheme, which allows single-storey rear extensions of up to 6 metres (attached or semi-detached) or 8 metres (detached) — but only after the council has notified your neighbours and had the chance to consider their objections.
Prior approval is quicker and cheaper than a full planning application, but it's still a decision the council makes, and it can be refused.
Getting proof: the Lawful Development Certificate
Here's the practical problem with PD: because you didn't apply for anything, you have nothing to show for it. That becomes an issue when you sell, when a buyer's solicitor asks how the extension was authorised.
A Lawful Development Certificate solves that. You apply to the council, they confirm your proposal is lawful under PD, and you get a formal document you can keep. The fee is half the householder planning application fee, and for most people it's well worth it — either before building (a "proposed" certificate) or afterwards (an "existing" one).
PD doesn't replace the other approvals
Even when your work is fully permitted development, you may still need:
- Building regulations approval — a separate system covering how the work is built (see the difference)
- Party wall notices if you're building on or near a shared boundary
- Landlord, freeholder or mortgage lender consent, and checks for restrictive covenants in your title deeds
The bottom line
Permitted development is a genuinely useful route — it can save months and a significant fee. But it rewards checking, not assuming. Before you commit to a design, it's worth having someone test it against the rules for your specific house.
If you'd like that done, get in touch — we'll tell you straight whether your project fits under PD, needs prior approval, or needs a full application.