When is an annexe not an annexe? The Planning Inspectorate considers.

The long running question of when an annexe is not an annexe (or at least, not a separate planning unit) has been revisited in a recent Planning Inspectorate ("PINS") case (APP/R5510/X/18/3206551, dated 8th January 2019). The case serves as a useful reminder that the issue of a certificate of lawfulness of an existing or proposed use or development ("CLEUD" or "CLOPUD") is not the end of the story. Minor modifications to a development, or a change in the way an annexe is inhabited, could still trigger a need to apply for planning permission, even in the absence of any structural changes.

In this case the appellant was seeking to convert an outbuilding located within the curtilage of the main dwellinghouse into a residential annexe (complete with bedroom, living area, kitchen and bathroom). The London Borough of Hillingdon had refused to grant a CLOPUD and the appellant had appealed this to the PINS. The Inspector was not therefore considering the planning merits of the case, but whether the use of the site had been lawful on the date the application was made.

The Inspector accepted that the additional primary accommodation was not incidental to the enjoyment of the existing dwellinghouse. However this didn't mean that a material change of use had necessarily occurred (and as such that planning permission would be required).

Rather the question was whether the annexe would result create a separate dwellinghouse (hence, planning unit). In reaching his decision, the Inspector took a number of factors into account. These included:

• Occupiers of the converted building: in this case they were the current owners of main dwelling, with family members moving into the main dwelling to provide practical support;
• Ownership of the site: in this case the site would remain owned by the appellants. The main house and annexe would not be split into separate titles or leased;
• Access to the site: the current single access to the highway would continue to serve the house and annexe with no separation of the two properties;
• Garden and parking: there was no demarcation between the two properties;
• Access to a shared space: the entrance to the outbuilding and the main dwelling onto a shared courtyard (indicating a close physical connection between the two units);
• Postal address and utilities: there would be no separate bills or addresses;
• Relative floor space: the area dedicated to residential use within the annexe would not be unduly large in comparison to the associated dwelling.

Taken together, these indicated that no separate planning unit would be created.

Notwithstanding the fact that the building would be capable of independent occupation, these factors led the Inspector to conclude that the proposed use of the building would not result in the creation of a separate planning unit. As such, the conversion would not be a material change of use, the appeal was allowed and a CLOPUD was granted. However, the Inspector also highlighted that if the building was used in a different manner in the future, even if no structural changes took place, the development may come to constitute a separate planning unit (and hence would require planning permission).

This article is for general guidance only. It provides useful information in a concise form. Action should not be taken without obtaining specific legal advice.