For an annexe to my house/flat?
The use of a house or a building within the garden of a house as an annexe does not need planning permission, provided that the additional living accommodation is connected to the main house. An example would be that the annexe is occupied by members of the family. An annexe cannot be used to create a new dwelling, independent of the main house. So you cannot rent out or sell the annexe without obtaining planning permission first.
If you want to build an extension or outbuilding in your garden to accommodate an annexe, then these structures may need planning permission. You may wish to use our self-certification forms to find out if the building you wish to erect needs planning permission. If you live in a flat, planning permission will be required for any new building within your garden. Please also check conditions attached to previous planning consents relating to the house in question, to make sure there is no restrictive condition that would prevent you from carrying out your proposed works.
Do I need planning permission?