A granny annexe can provide a practical and affordable solution for homeowners to provide self-contained accommodation to members of the family that are looking for privacy and a space to call their own.
From a planning point of view, however, they are considered separately from an outbuilding, and so cannot be built under Permitted Development Rights – a common misconception.
Outbuildings considered ‘incidental to the enjoyment of the main house’, such as a shed, poultry pen, beehives, garages or a gym can reasonably be considered incidental, and therefore can be built under Permitted Development – generally because people don’t stay or sleep in them.