Home / Garden rooms in Kent

Garden rooms in Kent

Updated 22 October 2026

A white timber garden building with French doors and a red roof

The short answer: most garden rooms in Kent don't need planning permission under the national rules. But a third of Kent is a National Landscape: the Kent Downs and the High Weald together cover 33% of the county¹, and the rules are tighter there.

Planning permission in Kent

Garden rooms count as outbuildings. Most can be built without planning permission if they sit behind the front of the house, have eaves no higher than 2.5m, and together with other buildings cover no more than half the garden. If any part of the room is within 2m of a boundary, the whole building must be no more than 2.5m tall; otherwise the limit is 4m with a dual-pitched roof, or 3m for any other roof. It must be single storey, with no veranda, balcony or raised platform over 30cm.² In the grounds of a listed building, any garden room needs permission, and so does a room used as primary living space, such as a bedroom.³ Our planning permission guide explains every rule.

Protected land in Kent

On designated land, which includes National Landscapes (the new name for Areas of Outstanding Natural Beauty) and conservation areas, you can't build a garden room to the side of the house without permission.⁴ In a National Landscape, national park or World Heritage Site, buildings more than 20m from the house can also cover no more than 10m² in total.²

Kent Downs National Landscape: the eighth largest National Landscape, running from the white cliffs of Dover to the Surrey and London border.¹
High Weald National Landscape: which, together with the Kent Downs, makes up a third of Kent.¹
Conservation areas: set by each district. Sevenoaks alone has 42.⁵

Green Belt

West Kent is heavily Green Belt. Sevenoaks District is 93% Green Belt, the second highest share in the country.⁶

Green Belt doesn't change the permitted development rules for garden rooms. It only matters if your room needs a full planning application, because the council will then judge it against Green Belt policy.

Which council to ask, and the 2028 change

Planning in Kent is handled by the 12 district councils and Medway Council.⁷ From 1 April 2028 they're being replaced by four new councils:⁸⁹

North: Dartford, Gravesham, Medway.
West: Sevenoaks, Tonbridge and Malling, Maidstone, Tunbridge Wells.
Mid: Swale, Ashford, Folkestone and Hythe.
East: Canterbury, Thanet, Dover.

Until then, apply to your current district council or Medway.

Building regulations

Building regulations don't normally apply to a garden room under 15m² with no sleeping accommodation, or one of 15m² to 30m² with no sleeping accommodation that is at least 1m from every boundary or built mostly of non-combustible materials.¹⁰ Running a new electrical circuit to it is notifiable work, so use a registered electrician. See our building regulations guide.

What a garden room costs in Kent

Installed garden rooms typically cost £1,200 to £2,500 per m² across the UK¹¹, and one industry cost guide puts the South East 15% to 25% higher.¹² So a 4m x 3m room in Kent might cost roughly £16,500 to £37,500 before extras. The average home in Kent sold for £411,259 in 2025⁷, so a garden room is a small share of a typical home's value.

Questions people ask

Do I need planning permission for a garden room in Kent?

Usually not, if it meets the national size and height limits. In the Kent Downs, the High Weald or a conservation area you can't build to the side of the house, and in the National Landscapes buildings over 20m from the house are limited to 10m² in total.

Is my home in the Kent Downs or High Weald?

Together they cover a third of Kent. Our free planning report checks your postcode, or use your council's planning map.

Which council do I apply to in Kent?

Your current district council or Medway until April 2028, then one of the four new councils.

Related guides

A small dark timber building beside a lawn and blue hydrangeas

Other areasRules and costs in other parts of the UK.

A small modern garden room with glass doors at the end of a fenced garden

Free planning reportCheck protected land at your postcode.

A garden path leading to a small building at the bottom of the garden

Garden room costsReal prices by size, with a calculator.

Sources

Kent Downs National Landscape, About us.
Planning Portal (England), Outbuildings: mini guide. Permitted development limits for outbuildings.
Ministry of Housing, Communities and Local Government, Permitted development rights for householders: technical guidance.
Planning Portal, Outbuildings. Designated land rules for outbuildings.
Sevenoaks District Council, Conservation is key for Sevenoaks District.
Sevenoaks District Council, Council criticises new planning framework, December 2024.
Kent County Council, Summary of Kent facts and figures: place.
Thanet District Council, Kent and Medway to be served by four unitary councils from 1 April 2028.
Swale Borough Council, Government decides on four new councils for Kent.
Planning Portal (England), Outbuildings: building regulations. When building regulations normally apply to outbuildings.
MyBuilder, Garden room cost price guide, updated 21 October 2026. UK price ranges for garden rooms, foundations, electrics, plumbing and fees.
BestBuilders, Garden room cost UK, updated 7 September 2026. An industry cost guide, not official data.