Do I Need Planning Permission for a Conservatory?

Most conservatories do not need planning permission in England, as they fall under Class A permitted development — provided they extend no more than 4 metres from the rear wall (detached houses) or 3 metres (semi-detached/terraced), have eaves no higher than 3 metres, and total extensions don't cover more than 50% of the garden. Building regulations are separate and may or may not apply depending on the conservatory's floor area and separation from the house. This guide covers the exact size limits, building regulations requirements, and common mistakes that make conservatories unlawful.

When a Conservatory Is Permitted Development

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Key Conservatory Planning Facts (England, 2024)

• Class A covers rear extensions including conservatories
• Max depth: 4m (detached) or 3m (semi/terraced) under standard PD
• Larger home extension scheme: up to 8m/6m with prior approval (£120 fee)
• Max eaves height: 3m | Max overall height: 4m (single storey)
• Building regulations exemption: under 30m², separated from house, ground level
• 50% garden coverage limit applies (all extensions + outbuildings combined)

A conservatory is treated the same as any other single-storey rear extension under the GPDO. Under Schedule 2, Part 1, Class A, you can build a conservatory without planning permission if it meets ALL of the following conditions:

Size Limits

• Maximum depth from the rear wall: 4 metres for detached houses, 3 metres for semi-detached and terraced houses (or up to 8m/6m under the larger home extension scheme with prior approval)
• Maximum height: 4 metres overall
• Maximum eaves height: 3 metres (or matching the existing eaves if lower)
• No more than half the garden (the area of land around the "original house") is covered by extensions and outbuildings combined

Position Rules

• Must not extend beyond the principal elevation (front of the house) or a side elevation that faces a highway
• Side extensions must be single storey with a maximum width of half the width of the original house
• Must be at least 2 metres from any boundary if over 2.5 metres in eaves height

Materials and Design

• Materials must be similar in appearance to the existing house (though this is interpreted loosely for conservatories)
• No verandas, balconies, or raised platforms (over 300mm)

"Original House" Matters

The "original house" means the house as it was first built, or as it existed on 1 July 1948 (whichever is later). Any previous extensions count against your permitted development allowance. If a previous owner added a 2-metre rear extension, you only have 1-2 metres left before hitting the limit.

The Larger Home Extension Scheme

Since 2013, the government has allowed larger single-storey rear extensions under a prior approval process (often called the "neighbour consultation scheme"). This allows:

• Up to 8 metres deep for detached houses
• Up to 6 metres deep for semi-detached and terraced houses

This isn't automatic permitted development — you must notify the council, and they must consult your immediate neighbours. If neighbours object, the council decides whether the impact is acceptable. The fee is currently £120.

This scheme applies to conservatories just as it applies to any other single-storey rear extension. It's been made permanent (it was originally temporary).

When You Need Planning Permission

You'll need a full planning application for a conservatory if:

• It exceeds the permitted development size limits
• It's at the front or side (facing a highway) of the house
• The property is a listed building
• Permitted development rights have been removed (by planning condition or Article 4 direction)
• The house is a flat or maisonette
• It would cover more than half the garden
• The property has already used its PD allowance with previous extensions

Conservation Areas

In conservation areas, you still have permitted development rights for rear conservatories, but with additional restrictions:

• Cladding the exterior is not permitted development
• Some areas have Article 4 directions removing PD rights entirely
• The design and materials may face more scrutiny if you need to apply

Building Regulations

This is where many homeowners get confused. Even if your conservatory doesn't need planning permission, it may need building regulations approval.

When Building Regulations Apply

A conservatory is exempt from building regulations if ALL of the following are true:

• It is at ground level
• The floor area is less than 30 square metres
• The glazing complies with safety glazing requirements (Part K/N)
• There is a separating wall and door between the conservatory and the main house (the existing external wall is kept or a new separation is created)
• Any fixed electrical installations comply with Part P
• The heating system is independent from the main house (or extends the existing system with separate temperature controls)

If you remove the wall between the house and the conservatory to create an open-plan space, the building regulations exemption is lost, and the conservatory must comply fully — including structural, thermal, and energy performance standards.

The Wall Removal Trap

Many people build a conservatory under the building regulations exemption, then knock through the separating wall later. This technically means:

• The conservatory is no longer exempt from building regulations
• The whole structure needs to meet current standards (thermal performance, structural integrity, foundations)
• A retrospective building regulations application may be needed

Building control officers increasingly check for this, especially during property sales.

Conservatory vs Extension: What's the Difference?

For planning permission purposes, there's no difference — a conservatory is just a type of extension. The same permitted development rules apply whether you're building a brick extension or a glass conservatory. If you're also considering other additions, the Class D rules for porches are separate from these extension rules, and garages follow either Class A (attached) or Class E outbuilding rules depending on whether they're connected to the house.

For building regulations, conservatories have the exemption described above (if conditions are met), while regular extensions must always comply with building regulations.

The key distinction is usually about the proportion of glazing:

• A conservatory typically has at least 50% of its wall area and 75% of its roof area glazed
• An orangery has more solid walls with a glazed roof lantern
• A standard extension has conventional walls and roof

All three follow the same planning rules, but the building regulations implications differ.

Party Wall Considerations

If your conservatory is built within 3 metres of a neighbouring building (measuring from the bottom of the neighbour's foundations), the Party Wall Act 1996 applies. You must:

1. Serve a party wall notice on affected neighbours at least 2 months before work starts
2. If they don't consent, appoint a party wall surveyor
3. A party wall award is prepared before work begins

This is separate from both planning permission and building regulations. Failure to serve notice doesn't make the conservatory unlawful, but it leaves you open to an injunction or damages claim.

Foundations and Ground Conditions

Conservatories need proper foundations — typically strip foundations or a concrete slab. The depth depends on:

• Soil type — clay soils need deeper foundations (often 1 metre+) due to shrinkage
• Trees nearby — tree roots can cause subsidence; foundations may need to be deeper (sometimes 2-3 metres near large trees)
• Drainage — you may need to reroute drains that run under the conservatory footprint

This is a building regulations and practical construction issue, not a planning issue, but it significantly affects cost.

Costs

A conservatory typically costs:

• Budget UPVC conservatory: £5,000-£12,000
• Mid-range conservatory: £12,000-£25,000
• High-end orangery/conservatory: £25,000-£50,000+
• Planning application fee (if needed): £258, with decisions typically within 8 weeks
• Building regulations application (if needed): £200-£500
• Party wall surveyor (if needed): £700-£1,500 per neighbour

Tips for Avoiding Problems

1. Measure from the original rear wall — not from any previous extensions
2. Check previous extensions — they count against your PD allowance
3. Keep the separating wall if you want the building regulations exemption
4. Serve party wall notices early — delays here can delay your whole project
5. Consider a lawful development certificate if you want written confirmation the conservatory is permitted development
6. Check your local council's approach — some are stricter than others on enforcement. Check your local council's planning portal, e.g. Sheffield or Liverpool, for local restrictions
7. If a conservatory has already been built beyond the permitted development limits, retrospective planning permission is a viable option — submit an application before selling

Frequently Asked Questions

Can I build a conservatory without planning permission?

Yes, in most cases. A rear conservatory up to 4 metres deep (3 metres for semi-detached/terraced houses), under 4 metres high, and covering less than half the garden is usually permitted development. Exceptions apply for listed buildings, flats, and properties where PD rights have been removed.

Do I need building regulations for a conservatory?

Not if the conservatory is under 30m², at ground level, has safety glazing, maintains a separating wall and door from the main house, and has an independent or separately controlled heating system. If you remove the wall between the house and conservatory, building regulations apply.

How close to the boundary can I build a conservatory?

If the conservatory is under 2.5 metres high at the eaves, you can build right up to the boundary. Over 2.5 metres eaves height, you must be at least 2 metres from any boundary.

Can I build a front conservatory?

A front conservatory is not permitted development and will always need planning permission. Councils generally resist front extensions as they change the streetscape.

Does a conservatory add value to my house?

Conservatories typically add 5-10% to property value if well-designed and properly built. Poorly built or poorly insulated conservatories can actually deter buyers.

Can my neighbour object to my conservatory?

If it's permitted development, there's no formal consultation. Under the larger home extension scheme (prior approval), neighbours are consulted. For a full planning application, neighbours are notified and can submit objections.

What about orangeries — are the rules different?

No. Orangeries follow the same planning rules as conservatories. The only difference is in building regulations — because orangeries have more solid construction, they're less likely to qualify for the building regulations exemption and are more likely to be treated as full extensions.

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Further Reading

Related Guides

• How to Appeal a Planning Decision
• Permitted Development Rights Explained
• Planning Enforcement: When Rules Are Broken
• What Are Material Planning Considerations?
• Conservation Areas and Planning
• How Much Does Planning Permission Cost?
• How Long Does Planning Permission Take?
• Retrospective Planning Permission
• Do I Need Planning Permission for a Porch?
• Do I Need Planning Permission for a Garage?

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