Granny Annexe in the garden – does it need planning permission?

A popular question that we are often asked is; can I add a Granny Annexe to my back garden? Can my Nan or Grandad move into the new structure?

Does it need planning permission for the Granny annexe?

Whilst Part 1, Class E allows for outbuildings, if the building is intended to be a separate self-contained dwelling then it will require planning permission. Class E allows for the erection of an outbuilding on up to 50% of the land around the home, which includes extensions, sheds and other outbuildings.

But does it require planning if used as a bedroom for a relative to sleep in? Let’s dive in a bit deeper.

The Permitted development rights for householders – Technical Guidance isays the following as far as a Granny Annexe is concerned.

Class E sets out the rules on permitted development for buildings etc within the curtilage of a house (see page 7). Buildings which are attached to the house are not permitted under Class E (they would be subject to the rules in Class A). Buildings under Class E should be built for purposes incidental to the enjoyment of the house.

Paragraph E.4 of Class E indicates that purposes incidental to the enjoyment of the house includes the keeping of poultry, bees, pet animals, birds or other livestock for the domestic needs or personal enjoyment of the occupants of the house. 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 house would not, however, cover normal residential uses, such as separate self-contained accommodation or the use of an outbuilding for primary living accommodation such as a bedroom, bathroom, or kitchen.

Granny Annexe

So this would suggest that the use of an annexe for someone to sleep in wouldn’t be compliant with Class E rights.

However, we would argue that a bedroom in the outbuilding or annexe would be an incidental use to the main dwelling. Various inspectorate appeal cases have backed this up.

What is important is that you do not create a separate dwelling. Therefore, whilst sleeping might be acceptable, other normal living requirements ought to take place in the main dwelling. For example cooking. It should be acceptable to have a shower, toilet and perhaps somewhere to relax – but we would leave the cooking of a Sunday roast to the kitchen in the house.


How to create a self-contained Granny annexe legally


That said there is nothing to stop you from creating say a gym for the use of the residents of the house, then at a later date apply for permission to convert that legal outbuilding into a more self-contained granny annexe – completely different scenario. A gym might require a small kitchenette for mixing of sports drinks and a shower for refreshing afterwards. However, I would recommend getting a lawful development certificate once the construction is complete of the gym or similar outbuilding. This would be a change of use.

You can also request change of use permission to convert an external garage into living accommodation as a granny annexe.

Or maybe you might wish to convert an internal garage into living space as this is not development. Generally you can replace the garage door with a window unless you are in a conservation area, listed building or a previous planning condition, especially in new builds, prevents this.

So the answer to ‘can you build a granny annexe?’ – yes you can, however it would require planning permission for self-contained living with a bedroom, bathroom etc, unless converting from an established outbuilding. Then it is just a change of use request.


Page Updated: 12th February 2024