Garden Rooms and Permitted Development

Exploring the world of garden rooms? Understanding permitted development rights is key. Typically sidestepping the need for planning permission, these rights offer a streamlined approach to expanding your property. However, complexities abound—considerations for location, building types, and dimensions are critical. This guide demystifies the intricacies, providing an insightful overview. While comprehensive, consulting your local planning office is paramount for tailored advice based on your property’s unique circumstances.

If you are thinking about investing in a garden room, you will probably be wondering whether you need planning permission for your building.

Most garden rooms can be built under your permitted development rights. Those rights enable you to improve and extend your home without the need for planning permission. But as with any laws and regulations, the rules that govern permitted development rights are complex. There are conditions and limitations that restrict what you can build, where you can build it and what you can use that structure for. Your plans for your garden room may also be impacted by where you live as there are specific rules for certain locations such as National Parks and conservation areas. It is vital that you establish whether you require planning permission for your building before proceeding with your project.

This guide should help you to make the right decisions. Please note that no guidance can encompass every possible situation as properties and their locations vary so greatly. It is your responsibility to establish whether planning permission is required. If you are in any doubt as to whether you require planning permission, consult with your local planning office. It is possible to apply via your local planning office for a ‘Householder Certificate of Lawfulness’ which will confirm that you can undertake your project under your permitted development rights. This certificate could prove useful if you ever wish to sell the property and could be requested during the conveyancing process.

Permitted developments rights are essentially a national grant of planning permission that enable homeowners to make improvements to their properties without the need to apply for planning permission from their local authority.

There are costs and delays associated with gaining planning permission. Permitted development rights were established to ensure that such inconveniences could be avoided when they would be out of proportion with the impact of the project on neighbours, the community and the environment.

Permitted development rights in England are set out in the Town and Country Planning (General Permitted Development) (England) Order 2015.

Please be aware that permitted development rights do not apply to flats, maisonettes or listed buildings. It is also worth noting that permitted development rights many have been removed from any area or property by the local authority courtesy of an article 4 direction. It is always a good idea to check that your home has not been the subject of an article 4 direction.

The regulations concerning permitted development rights feature certain terms that you may not be familiar with. An understanding of those terms and their meanings in the context of permitted development is important.

Here are the relevant terms that appear in the government’s guidance and how they are defined:

  • “Article 2(3) land”
    this means land located within a National Park, the Broads, an area of outstanding natural beauty, a conservation area, and within World Heritage Sites.
  • “Building”
    means any part of a building and includes any structure or erection but does not include walls or fences that enclose the structure.
  • “Dwellinghouse“ or “house”
    a domestic building that does not contain flats or maisonettes.
  • “Existing”
    refers to a building as it existed immediately before the permitted development is undertaken. The existing house will include any prior development to it, such as an extension.
  • “Height”
    any references to the height of a building is the height measured from ground level. Here, ground level means the ground adjacent to the building. Where the ground is sloping, the reference point is the highest ground that is next to the building.
  • “Highway”
    means a public right of way such as a public road, public footpath or bridleway and this also includes unadopted streets and private roads.
  • “Original”
    original building means a building as it existed on 1 July 1948 if it was built prior to that date. If it was built after that date, the term refers to the building as it was first built.
  • “Raised”
    in relation to a platform means a platform with a height greater than 0.3 metres.
  • “Unadopted street”
    means a street not being a highway maintainable at the public expense within the meaning of the Highways Act 1980.
  • “Curtilage”
    usually this is the area of land within which a house sits, or to which it is attached, such as the garden. However, in the case of houses with large grounds, a smaller area may be designated as the curtilage of the property.
  • “Principal elevation”
    in most cases the principal elevation will be that part of the house which fronts the main highway serving the house and that would be considered the front of the house. Advice should be sought if it isn’t clear which elevation is the principal elevation such as when a property occupies a corner plot.

As permitted development rights encompass a wide variety of buildings and structures, the associated rules are divided into sections known as parts. The rules regarding developments within the curtilage of a house feature in Part 1 of the rules.

Part 1 of the rules is sub-divided into classes covering extensions, windows, roofs, loft conversions, chimneys, driveways, antennae and porches etc. Garden rooms are outbuildings which are covered by Class E.

Class E permitted developments include buildings constructed for a purpose that is incidental to the enjoyment of the dwellinghouse. Buildings which are attached to the house such as extensions are not permitted under Class E rights. They are covered by Class A permitted development rights.

It is the word incidental that is key here and so it is crucial to understand what incidental means in this context. The dictionary definition of incidental is “happening as a minor accompaniment to something else”. When it comes to garden buildings, purposes incidental to the house would not encompass the usual residential uses such as living accommodation including bedrooms, bathrooms and kitchens. A home office could be considered incidental if you don’t regularly receive visitors to it but a yoga studio would probably not be a permitted development if you use it to host classes. The studio would then be treated a commercial premises.

Class E limits and restrictions

Unfortunately, there are specific limitations to permitted development rights that you should be aware of. Development is not permitted under Class E if:

  1. Permission to use the dwellinghouse as a dwellinghouse has been granted only by virtue of Class M, N, P, PA or Q of Part 3 of the Schedule (change its use).

    In other words, if your dwellinghouse was previously a commercial building and its use was changed, you may not be able to build a garden room without planning permission. The legislation regarding change of use is complex but can be explored here.

  2. The total area of ground covered by buildings, enclosures and containers within the curtilage of the property (other than the original dwellinghouse) would exceed 50% of the total area of the curtilage (excluding the ground area of the original dwellinghouse).

    To see whether you can proceed with your garden room under your permitted development rights, you need to make the following calculations:

    A – Calculate the total area of your curtilage.
    B – Calculate the area covered by the original dwelling house (bearing in mind the definition of original outlined above).
    C – Calculate the area covered by any outbuildings, enclosures and containers including your proposed garden room.
    D – Calculate the area occupied by any additions to the original house such as extensions.

    Then, confirm that the area covered by C + D would be less than 50% of A – B.

    50% rule of the total area of the curtilage of the property

  3. Any part of the building would be situated on land forward of a wall forming the principal elevation of the original dwellinghouse.

    For the meaning of principle elevation, please see above. To establish whether your building would be forward of the principal elevation, consider a hypothetical line drawn through that elevation to the side boundary of the land surrounding the house. You would need planning permission if any part of the garden room would be forward of that line.

    For example:

    building situated forward of principal elevation of the original dwellinghouse

    Note that if the principal elevation comprises more than one wall facing in the same direction, all such walls will form part of the principal elevation.

    For example:

    building situated forward of all principal elevations of the original dwellinghouse

  4. The building would have more than one storey.

    Buildings, including garden rooms, that are to have more than one storey will always require planning permission.

  5. The height of the building would exceed:

    A)  4 metres in the case of a building with a dual-pitched roof or hipped roof (a roof that slopes on four sides).

    Height of the building would exceed 4 metres for dual pitched or hipped roofs

    B)  2.5 metres in the case of a building within 2 metres of the boundary of the curtilage of the dwellinghouse.

    Height of the building would exceed 2.5 metres

    C) 3 metres in the case of a building with a mono-pitched-roof.

    Height of the building would exceed 3 metres for mono pitched roofs

    D) 3 metres in any other case.

    Height of the building would exceed 3 metres in any other case

    The height of the building must be measured from the highest ground level immediately adjacent to the building and to its highest point. If your building is to be located within 2 metres of a boundary, the height restriction of 2.5 metres will likely mean your garden room will need to be completed by a flat roof.

  6. The height of the eaves of the building would exceed 2.5 metres.

    The eaves of a building are considered to be the lowest point of a roof slope or where a flat roof meets the outside wall of the building.

    Height of the eaves of the building would exceed 2.5 metres

  7. The building would be situated within the curtilage of a listed building.

  8. The building would include a veranda, balcony or raised platform.

    Note that for the purpose of permitted development, the term raised refers to a feature that is more than 0.3 metres above the ground.

    Garden room situated more than 20 metres from dwellinghouse and exceed 10 square metres

  9. The building is a dwelling.

    In other words, if the garden room is to self-contained accommodation.

  10. If the garden room is to be situated more than 20 metres from any wall of the dwellinghouse and would exceed 10 square metres, it would not be a permitted development if it is within the curtilage of a dwellinghouse which is within a World Heritage Site, a national park, an area of outstanding natural beauty or the Broads.

    You should also note that in the specified locations, the total area of ground which may be covered by outbuildings that are more than 20 metres from any wall of a house is 10 square metres. This means that any existing structures such as sheds and greenhouses must be factored into your calculations.

    Garden room situated more than 20 metres from dwellinghouse and exceed 10 square metres

    In addition, outbuildings sited between a side wall and the boundary of the land surrounding the house are not permitted developments in a World Heritage Site, a national park, an area of outstanding natural beauty or the Broads.

    Outbuilding sited between side wall and boundary

Some projects that can proceed under permitted development rights will need to comply with building regulations. However, most garden rooms are exempt. The government’s Planning Portal states:

“Building regulations will not normally apply if the floor area of the building is less than 15 square meters and contains NO sleeping accommodation. If the floor area of the building is between 15 square meters and 30 square meters, you will not normally be required to apply for building regulations approval providing that the building contains NO sleeping accommodation and is either at least one meter from any boundary or it is constructed of substantially non-combustible material

You have probably heard many anecdotes about problems with planning departments and seemingly unreasonable planning decisions.

But planning officers are generally easy to deal with and reasonable. They will be happy to proffer advice and to discuss your ideas for your garden room.

Should you need to apply for planning permission, you will require a scale drawing of your proposed building and a site map of your plot. The latter can be obtained via the Planning Portal for a small fee. In addition, you will need to provide details of the materials that will be used to construct the building and you will have to explain how you intend to control rainwater runoff from the structure. Your garden room supplier should be able provide all relevant information concerning materials and the management of rainwater.

There is a charge to make a planning application which must be paid at the time of submitting the application. It would typically take around 8 weeks to gain a planning decision, but the length of the process varies according to which local authority you are dealing with and how busy they happen to be when you apply.

Don’t be intimidated by the thought of applying for planning permission. It really isn’t that difficult and most applications concerning garden rooms are successful.

Your garden room can likely be built under your permitted development rights if:

  • Your dwellinghouse was not created by a change of use.
  • The garden room does not feature accommodation.
  • The building will not be attached to the dwelling house.
  • Your outbuildings and additions including the garden room do not cover more than 50% of the curtilage of your dwellinghouse excluding the area covered by the dwelling.
  • The garden room is not to be positioned forward of the principal elevation of the dwelling.
  • The proposed building is single storey.
  • The height of the building does not exceed 4 metres if it has a dual-pitched roof or does not exceed 2.5 metres if located within 2m of a boundary, or 3 metres in all other cases.
  • The height of the eaves does not exceed 2.5 metres.
  • The dwelling house is not a listed building
  • The dwelling house is not located in a national park, conservation area, area of outstanding natural beauty or the Broads.

The rules governing permitted development in Wales are very similar to those in England. However, if you are planning to build a garden room in Wales, please note the following limitations also apply.

Development is not permitted by class E if:

  1. Any part of the building would extend beyond a wall comprised in a side elevation of the existing dwellinghouse and would be nearer to the highway than either the wall comprised in that side elevation which is nearest to the highway or any point 5 metres from the highway, whichever is the nearer to the highway.
  2. Any part of the building would be situated within 2 metres of the dwellinghouse and exceed 1.5 metres in height.

Guidance regarding permitted development rights for householders in Wales can b

Most permitted development rules in Scotland regarding garden buildings are similar to those that apply in England. However, there is one notable exception:

In the case of dwellinghouses located in conservation areas, the floor area of an outbuilding cannot exceed 8 square metres (4 square metres if within the curtilage of a listed building).

Householder permitted development rights guidance for Scotland is available here.

Permitted development rights are somewhat complex. But don’t be put off! Most garden rooms will prove to be permitted developments and your local planning office will help you to decide whether you need to make a planning application. A garden room will always be a significant asset and one that is worth tackling a few rules and regulations to achieve.

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