I think its time to set the record straight once and for all.
There is a lot of mis-information about granny annexe planning permission available on the internet.
The situation is straight forward. If a garden building is going to be slept in, it needs planning permission.
The government is quite clear about this. It is explained on page 40 of the government document Permitted Development for Householders-Technical Guidance. – for England and Wales.
As I explain in my own guide to planning permission for garden buildings, everything hinges on the definition of the word incidental. One of the criterion for deciding if a garden building needs planning permission is whether or not it will be used for an incidental purpose.
The Permitted Development for Householders-Technical Guidance makes it quite clear that a building that contains sleeping accommodation is not incidental:
But the rules also allow, subject to the conditions and limitations below, a large range of other buildings on land surrounding a house. Examples could include common buildings such as garden sheds, other storage buildings, garages, and garden decking as long as they can be properly be described as having a purpose incidental to the enjoyment of the house. A purpose incidental to a dwelling house would not cover normal residential uses, such as separate self-contained accommodation nor the use of an outbuilding for primary living accommodation such as a bedroom, bathroom, or kitchen.”
Nor is it explained in the interactive guide on the Government website.
You have to delve deeper into the full explanation in the Permitted Development for Householders-Technical Guidance. to find out that granny annexes need planning permission.
This is why so many people, both garden building suppliers and the general public are confused by the rules.
I hope this helps.
To read more about granny annexes please visit our granny annexe page.