Sussex, Surrey & Kent · 6 min read
Garden Annexe Planning Rules: What Sussex, Surrey and Kent Councils Expect
A garden annexe for family is different from a garden office in planning terms. Here is what changes and how to approach your council.
Garden annexe with timber cladding built for family use in Horsham, West Sussex
This is general guidance, not planning advice. Rules vary by council and site, especially in conservation areas, AONBs such as the Surrey Hills and High Weald, and around listed buildings.
Incidental vs ancillary use
Offices, gyms and studios are incidental and often fall under permitted development. Sleeping, cooking and bathing for a relative makes it ancillary accommodation, which normally needs planning permission and a condition tying it to the main house.
Local councils
We regularly work with Mid Sussex, Horsham, Guildford, Waverley, Sevenoaks, Tonbridge and Malling, and Tunbridge Wells councils. A pre-application enquiry is worth it on sensitive sites.
Common questions
- Does a garden annexe need planning permission?
- Usually yes if it includes sleeping accommodation, because permitted development covers outbuildings for incidental use only. An annexe tied to the main house as ancillary accommodation is commonly approved, but always confirm with your council.
- Does a garden annexe need building regulations?
- Yes. Any building with sleeping accommodation needs building regulations approval covering structure, insulation, fire safety, drainage and electrics.
Related services
Where we work
We design and build gardens, garden rooms and pergolas across Mid Sussex and the surrounding towns.
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