Do I need planning permission for a garden room?

The height limit depends on how near the room is to the edge of your garden.

Within 2 metres of a boundary, the whole building can be no more than 2.5 m high, measured from the ground to the highest point of the roof.

Further than 2 metres from every boundary, it can be up to 3 m high, or 4 m if it has a dual-pitched roof, which is two slopes meeting at a ridge. Either way the eaves, where the roof meets the walls, can be no higher than 2.5 m.

Most people want their room near a fence or a hedge, not in the middle of the lawn. That’s why our standard rooms are 2.5 m high: they can go where you’d actually put one.

It can’t go in front of the house. Planners call this being forward of the principal elevation, which usually means the wall that faces the road.

It can’t take up too much of the plot. Add up every extension, shed, garage and outbuilding. Together with the new room, they mustn’t cover more than half the land around the original house. “Original” means the house as it was first built, or as it stood on 1 July 1948 if it’s older than that, so an extension added since then counts towards the half.

And it can’t have a veranda, a balcony or a raised platform. Decking is fine as long as it’s no more than 30 cm above the ground.

The rules cover buildings used for something that goes with living in the house. An office for working from home, a studio, a gym, a music room and a hobby room all count.

A room that someone lives in doesn’t. Self-contained living accommodation, such as an annexe with its own kitchen and bathroom, needs planning permission. So does a room that someone sleeps in regularly. Both need building regulations approval as well.

We build those too. They take longer because of the applications, which we make for you.

Flats and maisonettes have no permitted development rights for outbuildings, so a garden room for a flat always needs an application.

Listed buildings need planning permission for any outbuilding in their grounds.

Conservation areas, national parks and other protected landscapes have tighter limits. In a conservation area, for example, anything to the side of the house needs permission. In a national park, outbuildings more than 20 m from the house are limited to 10 square metres in total.

Some houses, often on newer estates, had their permitted development rights removed when they were built. You can’t tell by looking, which is one reason we check.

Planning permission is about whether you can build it there. Building regulations are about how it’s built. A garden room can need neither, one or both, and floor area decides most of it.

Electrical work has to meet the regulations whatever the size of the room. Ours is done by our own electrician, who tests it and gives you the certificate.

Where a room does need building regulations approval, dealing with building control is included in our price.

Wales has its own permitted development rules. They’re similar in outline to the English ones on this page but not identical, so don’t rely on this guide for a Welsh address.

About a third of our rooms are in North Wales, and we check each of them against the Welsh rules.

We look up your address before we give you a fixed price: whether the house still has its permitted development rights, whether it’s listed, whether it’s in a conservation area or a protected landscape, and where the boundaries run. You get the answer in writing, and it costs nothing.

If your room needs planning permission, we draw it up and submit the application for £480 plus the council’s fee. Councils aim to decide within eight weeks.

If you’d like proof that no permission was needed, which can be useful when you come to sell, you can apply to the council for a lawful development certificate. We can do that for you too.