Permitted development rights explained
The plain-English guide to what you can build without a planning application — the GPDO classes, the limits, and what takes those rights away.
What permitted development actually is
When Parliament passes planning law, the default is simple: almost any development — from a rear extension to a new roof — needs planning permission. Permitted development is the exception. The government keeps a list of works so common, low-impact, or clearly defined that requiring an application every time would waste everyone’s time. Meet the conditions on that list and you don’t apply — you just build.
That list is the GPDO 2015 — the General Permitted Development Order. It’s organised into Parts (numbered 1 to 19), each covering a type of development, and within each Part the rights are grouped into lettered Classes (A, B, C…). Meet every condition in a Class and the work is lawful. Miss one and it falls outside — needing a full planning application, or not allowed at all.
In short: the rules all live in one place — the GPDO 2015 — split into Parts, then lettered Classes. Hit every condition in a Class and the work is lawful.
How the GPDO is built
Order → Parts → Classes. Homeowners live almost entirely in Part 1 — development within the curtilage of a house.
The classes that matter for homeowners
Almost everything homeowners care about sits in Schedule 2, Part 1 of the GPDO — development within the curtilage of a dwellinghouse. Here’s the quick reference, with a link to the full guide where we have one.
Rear, side and two-storey extensions. Single-storey rear depth 3m on terraces and semis, 4m on detached; 4m max height, 3m at the eaves; matching materials. Two-storey rear up to 3m deep, kept 7m from the rear boundary. Side extensions can’t exceed half the width of the house and aren’t allowed on designated land.
Roof additions (usually dormers) up to 40 m³ on terraces, 50 m³ on semis and detached. No dormers on the principal elevation facing a highway; the ridge can’t be raised. Removed entirely in conservation areas and on designated land.
Re-roofing and rooflights (Velux-type), which mustn’t project more than 0.15m above the roof plane and must match the existing roof in appearance. Listed buildings are excluded.
A porch up to 3 m² floor area and 3m high, set at least 2m back from any highway. Exceed any limit — even by a little — and you’re into planning-permission territory.
Sheds, home offices, garden rooms and pools behind the front elevation. Max 2.5m high within 2m of a boundary (4m otherwise, 3m eaves), and incidental to the house — independent living accommodation loses Class E. Extensions and outbuildings together can’t cover more than 50% of the curtilage.
The smaller classes: driveways and hard standing (porous materials for areas over 5 m²), chimney flues and vents, and antennas / satellite dishes — each with its own conditions.
Other Parts of the GPDO homeowners use
Part 1 is the main one, but a few other Parts apply to things homeowners do around the house.
- Part 2 — Minor operations. Fences, walls, and gates. Boundary treatments up to 2m in height (1m if next to a highway) are permitted development; listed buildings need consent. See the fences and walls guide.
- Part 14 — Renewable energy. Solar panels on a house roof, air-source heat pumps, and small wind turbines. Most installations are permitted development subject to technical limits (e.g. panels can’t project more than 0.2m from the roof slope).
- Part 16 — Electronic communications. Broadband and telecoms infrastructure, including some small external equipment.
Six things that remove your rights
Even when your project fits a Class, the property itself can disqualify it. The six main disqualifiers:
All external work needs listed building consent whatever the size, and most Class B and C rights disappear entirely.
Side extensions and cladding are removed, rear limits tighten, and Class B loft conversions go entirely.
Councils can withdraw specific rights street-by-street — often windows, painted brickwork, or paving the front garden.
National Parks, AONBs / National Landscapes, World Heritage Sites and The Broads roughly halve your limits and restrict side extensions.
Zones 2 and 3 restrict some outbuilding rights and may need a Flood Risk Assessment alongside any application.
PD is cumulative. Once past extensions and outbuildings cover half the original garden, there’s no more to add under PD.
How to prove your work is lawful
Permitted development comes with no automatic paperwork. Build within the rules and your work is lawful — but nothing proves it. That becomes a problem when you sell: the buyer’s solicitor will want evidence that any extension was lawful, and “I was sure” isn’t good enough.
The answer is a Lawful Development Certificate. You apply to your council for a Certificate of Lawful Use or Development — proposed (before you build) or existing (after) — and if the work meets the rules they issue a legally binding certificate confirming it’s lawful. It takes about 8 weeks and the fee is currently £274 for a proposed-use certificate. We generate a free LDC application pack with a full supporting statement based on your specific project and property.
Planning an extension that might be over the PD limits? Our £9 Full Report gives a personalised approval probability based on real recent decisions near your address, the 5 nearest comparable applications, the most common refusal reasons for your property type, and a concrete action plan — delivered as a PDF. Get my report — £9 or see a sample report.
Common questions
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