Do I Need Planning Permission for a Conservatory?

Usually not. In England, a single-storey rear conservatory can normally be built without planning permission under permitted development if it projects no more than 3 metres from the rear wall (4 metres on a detached house) and is no more than 4 metres high. Go beyond those limits, build at the front, or live in a listed building and you are likely to need permission.

A conservatory is treated under the same planning rules as a house extension, whether it is a compact lean-to, a luxury conservatory or a modern winter garden conservatory. Wales, Scotland and Northern Ireland have their own permitted development rules, so the limits below apply to England only.

When you usually do not need planning permission

A conservatory can usually be built under permitted development if it is attached to a house, is single storey and meets all of these limits:

• no more than 3 metres beyond the rear wall of the original house, or 4 metres on a detached house;

• no more than 4 metres high;

• eaves no higher than 3 metres if it is within 2 metres of a boundary;

• eaves and ridge no higher than those of the existing house;

• not forward of the principal elevation or on a side facing a highway;

• extensions and outbuildings together covering no more than half the land around the original house;

• side conservatories single storey, no more than 4 metres high and no wider than half the width of the original house.

Our guide to how big a conservatory can be without planning permission explains each limit in detail.

When planning permission is more likely

Planning permission becomes more likely when the conservatory is larger, taller, or positioned somewhere more sensitive. Front extensions almost always need permission. Side extensions can also be more restricted, especially on designated land. If the property is a flat or maisonette, householder permitted development rights do not apply.

You may also need planning permission if your house has already been extended in the past. The rules apply to the total enlargement of the original house, not just the new conservatory, so earlier extensions by previous owners can affect what is still allowed.

What about larger conservatories?

Some larger rear conservatories can still go ahead without full planning permission, but only through the prior approval process. This applies to larger single-storey rear extensions that project more than four and up to eight metres from the rear wall of a detached house, or more than three and up to six metres for any other house. In those cases, the local authority must be notified and adjoining neighbours are consulted; the council then has 42 days to decide.

This is where homeowners often get caught out. They hear that larger conservatories are “allowed” and assume nothing more needs to be done. In reality, prior approval is still a formal planning process, even though it is different from a standard householder application.

Listed buildings, conservation areas, and period homes

A listed home needs listed building consent for a conservatory. In a conservation area, National Landscape (formerly AONB), national park or other designated land, permitted development rights are more restricted: side extensions are not permitted development and the larger home extension route is not available, although a modest rear conservatory can still qualify. Check with the council before work starts.

Planning permission and building regulations are different

Even if you do not need planning permission, building regulations are a separate issue. A conservatory is usually exempt if it is at ground level, no more than 30 square metres, separated from the house by external-quality doors, windows or walls, has independent heating with its own controls, and meets the safety glazing rules. Remove those separating doors to make the space open-plan, or create a new structural opening, and building regulations approval is normally required. Our guide to building regulations for a conservatory covers the detail.

A simple checklist before you move forward

Before committing to a design, check:

• Is the property a house rather than a flat or maisonette?

• Has it been extended before, and how much allowance is left?

• Is the conservatory going at the rear, side or front?

• Is the home listed, or in a conservation area or other designated land?

• Has an Article 4 Direction or an earlier planning condition removed permitted development rights?

• If you are unsure, apply for a Lawful Development Certificate, which gives formal confirmation that the conservatory is lawful before you build.

For an orangery, the same rules apply; see our guide to planning permission for an orangery.

Conservatory planning questions, answered

Do I need planning permission for a conservatory on a semi-detached house?

Not usually, if it projects no more than 3 metres from the rear wall and meets the other limits. Up to 6 metres is possible through prior approval.

Can I build a conservatory in a side return without planning permission?

Often, if it is single storey, no more than 4 metres high and no wider than half the original house, and the house is not on designated land. A wraparound that extends to both the side and the rear usually needs planning permission.

Do I need planning permission to replace an existing conservatory?

Not usually for a like-for-like replacement on the same footprint within permitted development limits. A larger replacement, or one on a listed building, is assessed as a new extension.

Talk to our design team

If you would like us to check the planning route for your home, talk to our design team.