Do you need planning permission for a garden office?

Permitted development for garden buildings

Garden offices are treated as outbuildings, and in England most outbuildings fall under permitted development. That means you can build without applying for planning permission if the building meets all of these limits:

• It is single storey, with eaves no higher than 2.5 metres
• It is no taller than 4 metres overall with a dual pitched roof, or 3 metres with any other roof
• It is no taller than 2.5 metres overall if it sits within 2 metres of a boundary
• It is not in front of the main face of the house
• Together with other outbuildings and extensions, it covers no more than half the garden
• It has no veranda, balcony or raised platform higher than 30 centimetres
• It is used for something incidental to the house, such as an office, studio or gym, and not for sleeping

The 2.5 metre rule

The limit people ask about most is the 2.5 metre rule. If you want the office near the bottom or side of the garden, within 2 metres of a fence or wall, the whole building must be no more than 2.5 metres tall. This is why so many garden offices have a flat roof and sit just under that height.

If you have the space to set the building more than 2 metres from every boundary, you can go up to 3 metres with a flat roof or 4 metres with a pitched one, which gives a much more generous ceiling inside.

When you will need permission

The limits are tighter in some places. In conservation areas, national parks, National Landscapes (formerly Areas of Outstanding Natural Beauty) and World Heritage Sites, outbuildings at the side of the house need permission, and so do larger ones further back. Any outbuilding at a listed building needs consent. Flats and maisonettes do not have these permitted development rights at all.

Some new build estates have had permitted development rights removed by a planning condition. If your house is fairly new, check its planning approval on the council website before you order anything. Wales, Scotland and Northern Ireland have their own versions of these rules.

Building regulations

Building regulations are a separate question from planning. A detached garden office with no sleeping accommodation does not normally need building regulations approval if its internal floor area is under 15 square metres. Between 15 and 30 square metres it is usually exempt too, as long as it is at least 1 metre from every boundary or built mostly from non combustible materials. Over 30 square metres, it needs approval.

The electrics are covered either way. Power run out to the garden must be installed by a registered electrician who can certify the work.

Adding a toilet or kitchenette

A toilet or small kitchenette does not by itself mean you need planning permission, but connecting to drains does need building regulations approval, and the drainage work is often the most expensive part. It can also make a council look harder at whether the building is really an office or a separate dwelling. Keep it clearly part of the house: no bedroom, and no letting it out.

Getting certainty

If you want proof that your office is within the rules, apply to the council for a Lawful Development Certificate. It costs much less than a planning application, and it is useful when you come to sell. A good garden building company will also tell you early on if a design is going to need permission.