Short answer

Many house extensions, loft conversions and garden rooms in England do not need planning permission because they are permitted development, as long as they stay within set size limits. Flats, listed buildings, conservation areas and homes covered by an Article 4 direction or planning condition are different. If in doubt, apply for a lawful development certificate.

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What are permitted development rights?

Permitted development rights are a national grant of planning permission for common home improvements. For houses in England they are set out in Part 1 of Schedule 2 to the General Permitted Development Order 2015 (the GPDO). If your project fits every limit and condition in the relevant class, you do not need to apply for planning permission. You may still need building regulations approval, and party wall notices if you build on or near a shared wall.

All size limits are measured from the original house, meaning the house as first built or as it stood on 1 July 1948. Earlier extensions by previous owners count towards your allowance. No householder rights have been widened in 2026: the 2025 and 2026 amendments to the GPDO changed heat pump, electric vehicle charging and commercial rights, not the extension, loft or outbuilding limits. Proposals consulted on in 2024 to enlarge householder rights have not been made law.

How big can an extension be under permitted development?

Class A covers extensions. The main limits are:

• Single storey rear: up to 3 metres deep for a semi-detached or terraced house, 4 metres for a detached house, and no more than 4 metres high.
• Larger home extension: up to 6 metres (semi-detached or terraced) or 8 metres (detached), single storey only, if you first get prior approval from the council. Neighbours get at least 21 days to comment and the council has 42 days to decide. If it has not decided within 42 days, you can go ahead. The fee is £249.
• Two storey rear: up to 3 metres deep and at least 7 metres from the rear boundary.
• Side: single storey, up to 4 metres high and no wider than half the width of the original house.
• Near a boundary: eaves no higher than 3 metres if within 2 metres of the boundary.
• Coverage: extensions and outbuildings together must not cover more than half the garden (the land around the original house).

Extensions cannot go forward of the front wall facing a road, and materials must look similar to the existing house. Upper floor side windows must be obscure glazed and fixed shut below 1.7 metres.

Do loft conversions, porches and garden rooms need planning permission?

Usually not, within these limits:

• Loft conversions (Class B): the extra roof space must not exceed 40 cubic metres for a terraced house or 50 cubic metres for other houses. Dormers cannot face the road on the front roof slope, cannot rise above the highest part of the roof and must usually be set back at least 20 centimetres from the eaves. Balconies and raised platforms are not allowed.
• Rooflights (Class C): must not stick out more than 15 centimetres from the roof slope.
• Porches (Class D): up to 3 square metres in ground area, 3 metres high, and not within 2 metres of a boundary with a road.
• Garden rooms, sheds and outbuildings (Class E): single storey, eaves no higher than 2.5 metres, and a maximum height of 4 metres with a dual pitched roof or 3 metres otherwise. Anything within 2 metres of a boundary must be no higher than 2.5 metres. Not in front of the house.

An outbuilding must be used for purposes incidental to the house, such as a home office, gym or hobby room. Using it as a separate home or bedroom accommodation is outside Class E and needs planning permission.

When do permitted development rights not apply?

Check these before relying on permitted development:

• Flats and maisonettes: Part 1 rights apply only to houses, so most external works to a flat need planning permission.
• Listed buildings: you will usually need listed building consent for alterations, and outbuildings within the grounds of a listed building are not permitted development.
• Conservation areas, National Parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites (known as article 2(3) land): no side extensions, no two storey rear extensions, no cladding, no Class B loft extensions, no larger home extension scheme and no outbuildings to the side of the house.
• Article 4 directions: a council can remove specific rights in an area. Check your council's website.
• Planning conditions: a condition on the original permission for your home (common on newer estates) can remove permitted development rights.

Wales is different. Wales has its own order, the Town and Country Planning (General Permitted Development) Order 1995 as amended in Wales, with different depth, height and boundary distance rules. There is no larger home extension prior approval scheme in Wales. Check Welsh Government guidance rather than relying on the English figures above. Libra has been trained to differentiate between the laws in English, Wales, Scotland and Northern Ireland – however AI can make mistakes and Libra will connect you with a lawyer or free legal clinic when you need to check or you have a complicated situation.

Do I need planning permission, and how do I apply?

You need planning permission if your project goes beyond permitted development, your rights have been removed, or you are changing the use of the building. To get legal certainty that a project is permitted development, apply for a lawful development certificate for proposed works. It is optional but useful when you sell. The fee is half the normal planning fee, so £274 for a householder project in England.

You apply to your council, usually online through the Planning Portal, with drawings, a location plan and the fee. From 1 April 2026 the English fees are:

• £548 for a householder application for one house
• £249 for larger home extension prior approval
• £274 for a lawful development certificate for proposed householder works
• £89 to discharge householder conditions

The Welsh householder fee is £585 for applications from 1 December 2025. Councils aim to decide householder applications within 8 weeks. Permission normally lasts 3 years unless the decision notice says otherwise. Please check these fees as they may change over time.

How do I object to a neighbour's planning application?

Write to the council, usually through its planning portal, quoting the application reference, within the consultation period (normally 21 days from the neighbour letter or site notice). The council can only weigh material planning considerations, such as:

• loss of light, overshadowing or an overbearing effect
• overlooking and loss of privacy
• design, scale and effect on the street or a conservation area
• parking, highway safety and noise

Loss of a view, falling property values, boundary disputes and private covenants are not material, so leave them out. Keep your objection factual, refer to the council's local plan policies, and include photos from your property. For larger home extension prior approvals, the council considers only the effect on neighbouring amenity.

What if planning is refused or I get an enforcement notice?

If your householder application is refused, you can revise and resubmit it or appeal to the Planning Inspectorate (in Wales, Planning and Environment Decisions Wales) within 12 weeks of the decision notice. Most householder appeals are decided on written evidence. Standard planning application decisions have a longer appeal period.

Building without permission is not a crime in itself, but the council can ask you to apply for retrospective permission, issue an enforcement warning notice or serve an enforcement notice. Ignoring an enforcement notice once it takes effect is a criminal offence. You must appeal before the date the notice takes effect, which is at least 28 days after it is served. In England, you cannot argue on appeal that permission should be granted (ground (a)) if you had already made a retrospective planning application for the same development before the notice was issued and the council was still within its time to decide it.

Under the Levelling-up and Regeneration Act 2023, the time limit for enforcement in England is now 10 years for all breaches where building work was substantially completed, or a change of use happened, on or after 25 April 2024. The old 4 year limit still applies in Wales and to works completed in England before that date.

What are the key deadlines and time limits?

The main time limits for householders are:

• 21 days: the usual period to comment on a planning application, and the minimum for neighbours to object to a larger home extension.
• 42 days: the council's deadline to decide larger home extension prior approval. After that you can build.
• 8 weeks: the usual target for deciding a householder application or lawful development certificate.
• 12 weeks: to appeal a refused householder application (England and Wales), or 28 days if an enforcement notice has been served on the same development.
• Before the effective date: to appeal an enforcement notice, which is at least 28 days after service.
• 10 years: enforcement time limit in England for breaches from 25 April 2024. In Wales, 4 years for building works and changes of use to a home, and 10 years for other breaches.
• 3 years: to start work once permission is granted, unless the decision says otherwise.

What should you do next?

1. Find out whether your home is a house or a flat, and check with your council for listed status, conservation areas, Article 4 directions and conditions removing permitted development rights.
2. Measure your project against the permitted development limits, counting any earlier extensions to the original house.
3. If it fits, consider a lawful development certificate (£274 in England) before you build. If it does not, apply for planning permission (£548 in England).
4. Upload your plans, decision notice or enforcement notice to Libra and ask it to check whether permitted development applies, explain your options and deadlines, and draft an objection, application statement or appeal for you to check.
5. Diary every deadline straight away, especially the 12 week appeal window and the date an enforcement notice takes effect.
6. If the project is complex or enforcement action has started, find a lawyer or clinic through Libra.

Frequently asked questions

Can I build an extension without planning permission?

Yes, if your house has permitted development rights and the extension stays within the Class A limits, for example a single storey rear extension up to 3 metres deep (4 metres if detached). Up to 6 or 8 metres is possible through the prior approval scheme. Flats, listed buildings and conservation areas have tighter rules.

Do I need planning permission for a garden room?

Usually not, if it is single storey, behind the front of the house, no more than 2.5 metres high within 2 metres of a boundary, and used for purposes incidental to the house, such as an office or gym. It must not be a separate home or bedroom, and together with extensions must not cover more than half your garden.

Is a lawful development certificate a legal requirement?

No. You can build permitted development without one. A certificate is formal confirmation from the council that your project is lawful, which protects you from enforcement and reassures future buyers and their solicitors. For proposed householder works in England the fee is £274, half the householder application fee.

Can I apply for planning permission retrospectively?

Yes. You can apply for permission for work already carried out, and the council decides it in the same way as a normal application. If it is refused, you can appeal within 12 weeks. The council may take enforcement action if the work is unacceptable, so apply promptly if you realise you needed permission.

Can my neighbour stop my permitted development extension?

Not for standard permitted development, because no application is needed. For a larger home extension under the prior approval scheme, neighbours can object within 21 days and the council then considers the effect on their amenity, such as light and privacy. A neighbour may still raise party wall matters separately.

How long does the council have to take enforcement action?

In England, 10 years for any breach where work was substantially completed or a change of use began on or after 25 April 2024. Works completed before that date keep the old 4 year limit. In Wales, building works and changes of use to a single home still have a 4 year limit.

Can I build an office or a shed in my garden without planning permission?

Usually yes, under Class E in England, if it is for use incidental to the house (a home office you work from yourself counts). It must not be in front of the house, not cover more than half the garden with other buildings, and be under 2.5m high if within 2m of a boundary. Running a business with staff or customer visits may need permission.

Can I sleep in or rent out a garden room?

Not under permitted development. Outbuildings are only allowed for uses incidental to the house, so a bedroom annex, holiday let or separate home needs planning permission. Using a garden room as occasional overflow space for family is different from creating a self-contained unit, which councils treat as a new dwelling.

Can I put up a summer house, gym or cabin without planning permission?

These are treated like any other outbuilding. In England they are usually permitted development if they meet the Class E limits on height, position and garden coverage, and are not in the grounds of a listed building. Raised decking or a veranda over 30cm high needs permission. Check whether your permitted development rights have been removed.

How high can a fence, wall or gate be without planning permission?

Up to 2m high in most places, or 1m where it is next to a road used by vehicles or the footpath beside it. Anything higher needs planning permission, and listed buildings need consent whatever the height. The height is measured from the ground on your side, and replacing an existing fence at the same height is usually fine.

Do I need planning permission to pave my front garden or drop a kerb?

Paving more than 5 square metres of a front garden needs planning permission unless you use permeable materials or drain water to a lawn or border. A dropped kerb always needs your council's highways approval, and planning permission too if it opens onto a classified road. Apply before any work starts.

Do solar panels, heat pumps or EV chargers need planning permission?

Usually not on a house in England, as they are permitted development subject to size and position limits, and the rules for heat pumps and EV chargers were relaxed in 2025. Different rules apply to listed buildings, flats and some conservation areas. Check the current limits on the Planning Portal or ask Libra before you install.

Can I convert my garage without planning permission?

Converting an attached garage into a room is often permitted development if the outside changes are minor, such as replacing the door with a window and wall. Check your original planning permission for a condition keeping the garage for parking, which is common on newer estates. Building regulations approval is needed either way.

Ask Libra

• Can I build an office or a shed in my garden without planning permission?
• Is my rear extension permitted development or do I need planning permission?
• How high can my garden fence be without planning permission?
• Can I convert my garage without planning permission?
• How do I object to my neighbour's planning application?
• I have received a planning enforcement notice. What are my options?

Sources

• GPDO 2015, Schedule 2 Part 1 (householder permitted development, England)
• Town and Country Planning Act 1990, section 171B (enforcement time limits)
• GOV.UK: Lawful development certificates
• GOV.UK: Appeal a householder planning decision
• GOV.UK: Appeal an enforcement notice
• GOV.UK: Enforcement appeals, key changes under the Levelling-up and Regeneration Act
• Planning Portal: Planning application fees in England from 1 April 2026
• Welsh Government: Planning permission for extensions

This guide is general information about the law in England and Wales as at September 2026, not legal advice. For advice on your situation, ask Libra or find a lawyer through Libra.