If you are planning an extension, a loft conversion, a garden office or even solar panels, the first question is usually the same: do I need planning permission? For millions of homes in England the answer is often no, because permitted development rights grant automatic planning permission for many common projects. But those rights come with precise limits, they do not apply everywhere, and in 2026 the rules have moved again. This guide explains what permitted development rights are, exactly what you can build under them, what changed on 27 August 2026, and how to protect yourself before the builders arrive.
Permitted development rights are a general planning permission granted by Government rather than your local council. They allow specified building works and changes of use to go ahead without a planning application, provided every condition and limitation attached to the relevant class is met. If your project exceeds any limit, you need householder planning permission.
The rules live in Schedule 2 of the Town and Country Planning (General Permitted Development) (England) Order 2015, usually shortened to the GPDO. Part 1 of that schedule covers houses and is split into classes: Class A for extensions, Class AA for additional storeys, Class B for roof additions, Class D for porches, Class E for outbuildings and so on. Part 14 covers domestic renewable energy, including solar panels. The Government’s technical guidance for householders explains how each limit is measured, and the Planning Portal summarises the position for over 60 common projects.
One point catches many people out: the GPDO applies to England. Wales, Scotland and Northern Ireland have their own versions with different thresholds, so always check the rules for the nation your property sits in.
Householder permitted development rights attach to dwellinghouses, not to flats, maisonettes or converted buildings. If you own a flat, almost any external alteration will need a planning application. Houses created through permitted development change-of-use rights, for example a former office converted to a home, usually cannot then use householder rights for extensions either, as the Planning Portal notes.
Three further checks decide whether your rights are full, reduced or removed:
Planning conditions on earlier permissions can also remove rights, particularly on newer estates. A planning history check, which forms part of a good building survey, will flag this before you design around a right you do not have.
The table below summarises the main householder limits in England. Every figure is measured from the “original house”, meaning the house as first built or as it stood on 1 July 1948, so any previous extension counts against your allowance.
| Project | GPDO class | Key limits under permitted development | Prior approval needed? |
|---|---|---|---|
| Single-storey rear extension | Part 1, Class A | Max 4 m deep (detached) or 3 m (semi or terrace); max 4 m high; eaves max 3 m if within 2 m of a boundary | No |
| Larger single-storey rear extension | Part 1, Class A | Up to 8 m (detached) or 6 m (other houses); not on article 2(3) land | Yes, neighbour consultation scheme |
| Two-storey rear extension | Part 1, Class A | Max 3 m deep; at least 7 m from the rear boundary; roof pitch to match | No |
| Side extension | Part 1, Class A | Single storey only; max half the width of the original house; max 4 m high; not on article 2(3) land | No |
| Additional storeys | Part 1, Class AA | Up to two storeys on a detached house, one on others, subject to height caps and a post-1948 build date | Yes |
| Loft conversion / dormer | Part 1, Class B | Max 50 m³ extra roof space (40 m³ terraces); no higher than the existing ridge; set back 20 cm from eaves; not on the principal elevation facing a highway | No |
| Porch | Part 1, Class D | Max 3 m² floor area; max 3 m high; at least 2 m from a highway boundary | No |
| Outbuilding or garden room | Part 1, Class E | Single storey; eaves max 2.5 m; overall max 4 m (dual pitch) or 3 m; 2.5 m if within 2 m of a boundary; not forward of the principal elevation; no self-contained accommodation | No |
| Roof-mounted solar panels | Part 14, Class A | Max 0.2 m protrusion above a pitched roof; max 0.6 m above a flat roof; not above the ridge; extra limits in conservation areas and World Heritage Sites | No |
| Stand-alone solar in the garden | Part 14, Class B | Panels max 9 m²; height max 4 m (2 m within 5 m of a boundary; 1 m if also forward of the principal elevation) | Sometimes (conservation areas and other article 2(3) land) |
Two overarching limits apply to almost everything in the table. No more than 50% of the land around the original house may be covered by buildings, and materials must be of similar appearance to the existing house. Verandas, balconies and raised platforms are never permitted development.
The “neighbour consultation scheme” lets you build a single-storey rear extension of up to 8 m on a detached house or 6 m on any other house without full planning permission. Before starting, you must notify the council, which writes to adjoining owners. Neighbours have 21 days to object; if they do, the council assesses the effect on their amenity and must decide within 42 days. Because these extensions almost always involve building at or near the boundary or excavating close to a neighbour’s foundations, they usually trigger the Party Wall etc. Act 1996 as well. Our complete guide to party wall agreements explains the notices and timescales.
The most significant 2026 development for householders is the Town and Country Planning (General Permitted Development) (England) (Amendment) Order 2026 (SI 2026/896). It was made on 29 July 2026 and came into force on 27 August 2026, rewriting Classes A and B of Part 14 for domestic solar equipment. The headline changes, taken directly from the Order, are:
Beyond solar, the wider picture is one of consultation rather than change. The Ministry of Housing, Communities and Local Government ran a consultation from 10 June to 5 August 2026 on further permitted development amendments, but these concerned RAAC-affected schools, assets of community value, closed defence sites and Environmental Delivery Plans rather than home extensions. The Planning and Infrastructure Act 2025, which received Royal Assent on 18 December 2025, reshapes fees, delegation and infrastructure consenting but does not alter householder permitted development rights. The 2024 proposals to allow 4 m rear extensions on terraces and to scrap the loft volume cap had still not been enacted as of September 2026, so the limits in the table above remain the law.
Yes. Permitted development only deals with planning. Building regulations approval is a separate regime that applies to almost all extensions, loft conversions and structural alterations, covering structure, fire safety, insulation, drainage and electrics. A garden room may escape building regulations if it is small and contains no sleeping accommodation, but an extension or dormer will not. See our building regulations guide for what inspectors look for.
Likewise, if your extension is built at the boundary, cuts into a shared wall or involves excavation within 3 m of a neighbour’s structure, you must serve notice under the Party Wall etc. Act 1996 whether or not planning permission is needed. Appointing one of Survey Merchant’s party wall surveyors before you finalise drawings avoids the common mistake of serving notices late and stalling the build.
A lawful development certificate (LDC) is optional but strongly recommended. It is a formal council decision confirming that your proposed or existing works are lawful under permitted development. Without it, you rely on your own interpretation of the GPDO, and if you have miscalculated the council can take enforcement action within the relevant time limits. An LDC also reassures buyers, conveyancers and mortgage lenders when you sell, and disputes about undocumented extensions are a regular cause of delayed sales.
The application requires accurate existing and proposed drawings. A measured survey by a suitably qualified surveyor removes the guesswork, and if the certificate is refused you will know before spending a penny on construction. For projects that fall just outside the limits, our comparison of pre-application advice versus a full planning application explains the alternative routes.
Permitted development is a rules-based system, and the rules are unforgiving of a few centimetres. A suitably qualified, accredited surveyor adds value at every stage: producing measured drawings of the existing house, checking the proposal against each class limit, identifying Article 4 directions and planning conditions from the planning history, preparing the LDC submission, serving party wall notices and designing the structure. Surveyors regulated or accredited by bodies such as the Royal Institution of Chartered Surveyors (RICS), the Chartered Institute of Building (CIOB) and the Residential Property Surveyors Association (RPSA) work to published professional standards and carry professional indemnity insurance, which matters if a council later challenges the work.
If the project adds value, for example a loft conversion or a large rear extension, an independent valuation before and after can also help you judge whether the spend is justified. Our guide on how to value a loft conversion sets out the approach. For a broader look at the evidence planners expect, read the role of surveys in planning permission.
Getting permitted development wrong is expensive, whether that means an enforcement notice, a stalled sale or a neighbour dispute. We recommend Survey Merchant because the service is built to remove those risks:
Ready to check what you can build? Book a surveyor with Survey Merchant or contact the team for a fixed-fee quote today.
Survey Merchant provides vetted RICS surveyors across 100+ UK locations at fixed fees:
→ Level 2 Home Survey (HomeBuyer Report)
→ Level 3 Building Survey (full structural survey)
→ RICS Red Book property valuations
→ Party wall surveyors — notices, awards & schedules of condition
→ Expert witness surveyors — CPR Part 35 reports for property disputes
