August 2022

Maintaining your conservatory

A conservatory has long been considered a quick and relatively inexpensive way to add much-needed space – and value – to your property. But whether you already have one or are thinking about adding one, it’s important that you obtain the correct planning permission and Building Regulations approval, particularly if you are thinking about selling the property in the near future. Without the relevant permissions in place, major problems can arise when trying to sell the house and the sale can fall through.

There are some fundamental differences to be aware of between Planning and Building Regulations across England and Wales, Scotland, and Northern Ireland, so read on to find out which guidance applies to your property.

Planning in England and Wales

Across England and Wales, planning permission for conservatories falls under the same rules as single-storey extensions, but Building Regulations are still required.

Permitted Development rights allow you to carry out some common home building projects without having to apply for planning permission, but there are exceptions. Under ‘permitted development’, planning permission is not needed for an extension such as a conservatory if:

  • no more than half the area of land around the original house* would be covered by additions or other buildings
  • extensions of more than one storey must not extend beyond the rear wall of the original house* by more than 3m or be within 7m of any boundary opposite the rear wall of the house
  • a single-storey rear extension does NOT extend beyond the rear wall of the original house* by more than 8m if a detached house or 6m if an attached house
  • no extension is further forward than the principal elevation or side elevation which fronts a highway
  • no extension is higher than the highest part of the roof of the original house*
  • the maximum height of the single-storey rear extension is 4m
  • the maximum height for the eaves of an extension must be within 2m of the boundary of 3m
  • the maximum eaves and ridge height of an extension must be no higher than existing house
  • a side extension is single storey and a maximum height of 4m and width no more than half that of the original house*
  • the roof pitch of an extension higher than one storey matches the existing house
  • there are no verandas, balconies or raised platforms
  • on designated land** permitted development is not allowed for rear extensions of more than one storey. They also cannot have any exterior cladding or side extensions.

*According to the Planning Authorities, the term ‘original house’ means the property as it was first built or as it stood on 1 July 1948 – if it was built before that date. Even if you have not built an extension to the house, you may need to check in case a previous owner has done so.

**The term ‘designated land’ includes National Parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.

While the majority of conservatories are added to the rear of the property, some home owners add structures to the side of the house. Conservatories built to the side need planning if:

  • they are more than single-storey or over 4 metres and/or they are wider than half the width of the ‘original house’
  • if the extension meets all the requirements for permitted development, it doesn’t need planning permission.

Building Regulations in England and Wales

Building Regulations are needed if the heating system is connected to the rest of the house. For the conservatory to be exempt from Building Regulations, it must have a heating system independent from the house. This is defined by having separate heating controls in the conservatory, e.g. a standalone electric radiator.

Making alterations to an existing conservatory

As technology evolves, many home owners are opting to update their conservatory roof from glass to materials like tile and slate. Be aware that this changes the nature of the structure from a conservatory to a single-storey extension. But as the structure is no longer deemed under the exemption of a ‘conservatory’ it does need to meet relevant building regulations.

Restrictive covenants

A covenant could stop any development or building work on the property or the surrounding land. If such an issue arises in your house sale or purchase, you should seek legal advice.


Planning in Scotland

Across Scotland, permitted development rights allow any enlargement of a dwelling by way of a single storey ground floor extension, including any alteration to the roof required for the purpose of the enlargement.

This covers the typical single storey extension to the rear of the property and includes conservatories, carports as well as other canopies or roofs, with or without walls.

However, the rules for permitted development depend on how many storeys (levels) your extension will have.

Single-storey extensions

If the development is only one storey, planning permission is not required as long as:

  • it is located at the back of the house
  • t doesn’t go back further than 3 metres if it’s a terraced house, or 4 metres if it isn’t
  • the height of the eaves (where the wall meets the roof) is no higher than 3 metres
  • it is not higher than 4 metres, including sloping roofs
  • it doesn’t cover more ground area than your house does, i.e., should not take up more than 50% of the outside space.
  • it doesn’t take up half the ‘curtilage’ – the grounds behind your home
  • it isn’t within a conservation area
  • it is not a listed property
  • the floor area of the extension should not be more than half of the original square footage of the property.

Multi-storey extensions

If the development is more than one storey, planning permission is not required as long as:

  • it is located at the back of the house
  • there’s at least 10 metres between the extension and the boundaries of your grounds
  • it isn’t higher than the house (exc. chimneys)
  • it doesn’t cover more ground area than your original house does
  • it doesn’t take up half the ‘curtilage’ – the grounds behind your home
  • it isn’t within a conservation area
  • it is not a listed property.

If the structure meets these guidelines, it will not need planning permission but a Certificate of Lawfulness should be obtained from the planning department. A building warrant (legal proof) is also required for all extensions and some conservatories, before building work begins

Important note: If the extension doesn’t meet the conditions for permitted development, planning permission is required.

Building Regulations in Scotland

Building (Scotland) Act 2003 defines a conservatory as a building attached to a dwelling with a door and any other building elements dividing it thermally from that dwelling, with translucent glazing (including frames) forming not less than either:

Planning permission is not required for a radiator, but it will be subject to building regulations if connected to the central heating in the main house as legally, a conservatory has its own independent heating source.



Planning in Northern Ireland

Most conservatory installations are viewed as permitted development. A conservatory or single-storey extension can be built without planning permission if:

  • it is a maximum height of 4m high or 3m high (if within 2m of a boundary)
  • the conservatory does not cover more than half the garden
  • the roof ridge or top point is not higher than the eaves of a property’s roof.

On that basis, planning permission is not generally required for conservatories and sunrooms but be aware of the following rules:

  • A conservatory attached to the house will be treated as an extension and therefore will need to comply with the rules set out in a single storey extension
  • Two storey or more houses can add up to two storeys under Permitted Development
  • The house cannot exceed 18 metres overall. Each storey cannot add more than 3.5 metres to the height. The storey must be on the principal part of the house and the roof pitch must be the same after as it was before
  • The permitted development rules have recently been relaxed, allowing you to build an extension without planning permission of up to six metres (or eight metres if your house is detached)
  • A conservatory can be built on the front of a house. This is because conservatories come under the category of a permitted development. This applies if the area surrounding the original house is not more than 50% covered by other buildings or additions.
  • In Northern Ireland planning permission is required for conservatories to the rear of the dwelling if, by adding it, the original footprint of the house has been increased by more than 40sqm
  • Planning permission is required for a conservatory of any size positioned to the side of a dwelling
  • If the property is a flat or maisonette, converted house, or listed building, then a conservatory may need planning permission. In general, planning permission is not needed on a typical house unless it falls under one of the above conditions
  • Most new-build conservatories with either a solid, tiled or glazed roof will not need planning permission, because they are covered under what is known as a ‘permitted development’
  • If these measures are not in place, the conservatory is technically an extension and separate Building Regulations apply
  • Building Regulations do not apply if it is an extension to a building, is at ground level, and has a floor area not exceeding 30m2
  • Conservatories must have at least 75% of the roof and 50% of the external wall made of translucent material. Glazing must conform to Building Regulations. A thermal break must remain between the dwelling and extension and no heating can be extended into or installed in the conservatory without an application being made.

Any development that falls outside these criteria will require approval with Building Regulations.