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Do I need planning permission to add a first-floor extension onto an existing ground floor extension?
Adding a storey on top of an extension will always require an application for planning permission.
If you want to add a storey on top of your house under permitted development rights, it must be on the principal part of the house.
If you want to add an additional storey on top of your house, it can be permitted development. It is only permitted development if it follows certain rules:
The current house
- Is not a building containing one or more flats, or a flat contained within such a building
- Was constructed between 1 July 1948 and 28 October 2018
- Has not already had additional storeys added to it
- Is not on Article 2(3) land or a site of special scientific interest
- Was not changed to be used as a house (from a previous non-residential use) under permitted development rights.
How many storeys can you add?
- If the house is one storey then one storey can be added
- If the house is two or more storeys then two storeys can be added
Where can the storeys be added?
- The additional storeys must be added to the principal part of the house. The principal part of the house is the main part of the house excluding any front, side or rear extension of a lower height (regardless of these being part of the original house or subsequent additions).
- Engineering operations must only include works within the existing curtilage of the house to strengthen existing walls and foundations
How high can it be?
- The house cannot exceed 18 metres in total height
- Each storey cannot add more than 3.5 metres to the total height
- If the house is not detached the total height cannot be more than 3.5 metres higher than the next highest building that the house is attached to, adjoins, or is in the same row as.
- The additional storeys must have an internal floor-to-ceiling height of no more than 3 metres, and no greater than the internal height of any existing storey within the principal part of the house.
What materials can be used?
The materials used must be of a similar appearance to those used in the construction of the exterior of the current house
Where can windows be placed?
Windows must not be placed in any wall or roof slope forming a side elevation of the house.
Following completion of development:
- The house must remain in use as a domestic residential property
- No visible support structures must remain on or attached to the exterior of the house
- The roof pitch of the principal part of the house must be the same as it was prior to the development.
If any of the limits set out above are exceeded then an application for planning permission will be required. If you are unsure, you should contact your local planning authority.
Common Questions
For houses, replacing windows with double glazing usually doesn’t require planning permission, provided the style and appearance are similar to the original. However, if you live in a flat/maisonette, listed building, or a conservation area, planning permission or listed building consent may be required, especially if the changes affect the external appearance.
Read more about planning permission for windows and doors for houses
Read about planning permission for windows and doors for flats and maisonettes
If an outdoor kitchen is not a permanent structure, then planning permission will normally not be required.
Where planning permission is required, it may be granted through permitted development rights, provided it meets the limits set out in legislation. Most outdoor kitchens fall within the set limits unless they are particularly tall or close to a boundary.
While there is no specific permitted development right for ‘outdoor kitchens’ it may be classified as an ‘outbuilding’.
You can view the limitations for outbuildings and outdoor kitchens in the relevant common project
If the structure exceeds the limits set out through permitted development rights, then it will require an application for planning permission.
Different rules may apply if you live in a listed building or conservation area. If this is the case, you may wish to consult your local planning authority.
Read about the building regulations that cover outdoor kitchens.
Demolishing a building may require planning permission or prior approval, depending on factors such as the building’s type, size, and location.
Before starting any demolition work, it’s important to consult your local planning authority to confirm what permissions are needed. This helps avoid the risk of enforcement action or legal consequences.
You will also need to ensure you conform to the building regulations around the demolishing of a building.
In most cases neither planning permission nor building control approval are required for replacing grass with artificial grass. If you live in a protected areas such as a conservation area, or listed building, it is best practice to contact your local planning authority to check whether any consents are required.
Find your local planning authority.
Certain types of development are granted planning permission by national legislation without the need to submit a planning application. This is known as 'permitted development'. In order to be eligible for these permitted development rights, each 'class' specified in the legislation has associated limitations and conditions that proposals must comply with.
One such condition on certain classes of permitted development is the need to submit an application to the local planning authority for its 'prior approval; or to determine if it’s 'prior approval' will be required.
This allows the local planning authority to consider the proposals, their likely impacts in regard to certain specific factors (e.g. transport and highways) and how these may be mitigated.
For more information on prior approval, read guidance on prior approval consent types.
