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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
A ‘P certificate’ may refer to confirmation that electrical installations within a building are compliant with Approved Document P of the building regulations.
An electrician who is Part P certified is able to self-certify domestic work they complete, meaning you do not have to submit a building notice. To ensure your electrician is Part P certified, use a registered competent person.
If the conservatory is not separated from the house by external quality walls, doors or windows, then it will lose its building regulations exempt status. As such it will be required to adhere to thermal efficiency rules and ventilation rules.
The new opening created from removal of the door will also need building regulations approval.
Find out more from our conservatories common project
Bricking up an external door is classified as permitted development, meaning an application for planning permission is not required to complete the works. You will need to ensure that any materials used are of a similar appearance to the existing exterior of the house.
If you live in a listed building, then you will require planning permission and listed building consent for the change. In this instance it is best practice to talk to your local planning authority.
Find your local planning authority.
Your planning application must be made up of:
- The necessary plans of the site
- The required supporting documentation
- The completed form
- The correct fee.
The local planning authority will not be able to process your application unless the mandatory supporting documentation has been provided. You can also attach any other relevant documentation which you think will help the local authority determine the application.
What supporting documentation must be provided depends on the application type, development type and local planning authority.
There are two levels of mandatory documents, national and local. If you’re applying online, the service will tell you what mandatory documentation you need to provide and allows you to attach the relevant documents. Most applications will require you to provide a location plan and a site plan.
In addition to the national list, your LPA may produce a list which details any specific documentation that is required to accompany the application. The requirements may vary according to the type of application, i.e. household, full, outline, etc. If you are applying online, this list is available from the supporting documents screen or your local planning authority’s website.
For more information around what to submit visit the how to apply section on Planning Portal.
Normally planning permission is not required for installing a toilet in an existing area of the property as the change is only internal. If the toilet is part of a wider project such as an extension permission may be required.
If you live in a listed building, then listed building consent will be required for any major changes.
Building regulations will apply to the installation of a toilet in a property, these will cover areas such as ventilation, plumbing and drainage, and size.
