Building an additional storey on to your house is considered to be permitted development (not requiring planning permission) subject to the following limits and conditions, and an application for the Local Authority’s prior approval.
If these limits and conditions are not met, then an application for Householder/Full Planning Permission will be required.
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 5 March 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.
Limitations on the proposed development:
- Number of additional storeys:
- One storey can be added to a single storey house
- Two storeys can be added if the house has more than one storey.
- Height increases:
- The house cannot exceed 18 metres in total height
- Each added storey cannot add more than 3.5 metres to the total height
- If not detached (e.g. terrace or semi) 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 be constructed on the principal part* of the house
- The additional storeys must not exceed three metres in height or the height of any existing storey in the principal part* of the house (measured internally from floor to ceiling)
- Engineering operations must only include works within the existing curtilage of the house to strengthen existing walls and foundations
- The materials used must be of a similar appearance to those used in the construction of the exterior of the current house
- 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.
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).
Article 2(3) designated land
This is defined as land within:
- a conservation area; or
- an area of outstanding natural beauty; or
- an area specified by the Secretary of State for the purposes of enhancement and protection of the natural beauty and amenity of the countryside; or
- the Broads; or
- a National Park; or
- a World Heritage Site.