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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
There are different planning fees for England and Wales, and many different application types depending on the work being carried out.
You can use the Planning Portal's fee calculator to work out fees for different kinds of proposal.
Use the fee calculator (England)
Use the fee calculator (Wales)
While every effort has been taken to ensure that the fee has been calculated correctly, the determination of whether a planning fee is correct is the responsibility of the relevant local planning authority, who will check the fee is correct when the application is submitted and validated.
Building above an attached garage is treated the same as adding a storey to the rest of your home. This is considered to be permitted development, not requiring an application for planning permission provided you meet the set rules and requirements.
You will still need to submit an application for prior approval to your local planning authority.
Read the list of rules and requirements for extending upwards.
Planning permission is not required to move an internal doorway, provided it does not impact the external appearance of the building. If the building is listed, you will require listed building consent for any changes to the building.
Building regulations may apply if the wall is load bearing or is part of a fire escape route.
Read more about windows and doors from our common projects.
You can usually put up new fences, gates or garden walls without planning permission, as long as you stay within permitted height limits. If the structure is adjacent to a highway (including footpaths), it must not exceed one metre in height. For all other boundaries, the maximum permitted height is two metres. Anything taller than these limits will require planning permission.
Removing a chimney stack may fall under permitted development rights, meaning no application for planning permission is required provided certain limits and conditions are met.
The permitted development right which covers this focuses on the installation, alteration or replacement of a chimney, note that this does not specifically mention removal. Rules in a conservation area may differ, in this instance you should contact your local planning authority directly to understand their position, and if the building is listed, then you will need listed building consent.
To ensure that the local planning authority will allow the removal of the chimney stack you can apply for a lawful development certificate. If approved, then no enforcement action can be taken against the change.
If the chimney is shared (i.e. as part of a terrace), you might need to discuss with relevant neighbour and obtain a party wall agreement.
Building regulations approval may not be required if you are removing the external chimney stack above the roof. If works progress to the internal chimney stack or breasts, then it will require building regulations to understand the structural impact.
Read more about planning and building regulations on Planning Portal.
