How Big Can A Building Be Without Planning Permission?

Emma Davey

Planning permission has always been one of the biggest challenges for those in the UK looking to build or add to their property. Construction is a heavily regulated field, and it’s crucial that the building you occupy meets a series of very strict standards. While this can often feel like a pain to overcome, all of the rules you have to follow make a lot of sense.

Some are designed to protect the environment, while others are intended to preserve the look and feel of your local area. Size always comes into your planning permission application, though many people aren’t sure how large they can build without having to request permission from their local council. Let’s take a look at some of the biggest questions people ask when they are trying to figure this out.

Do I need planning permission to build a building?

There is no simple answer to a question like this. If you’re starting with a fresh plot of land and want to build a full-sized house, you will almost certainly need permission to get started. For other structures, though, it’s worth building an understanding of the rules you have to follow.

What can I build without planning permission?

  • Sheds/Garages/Outbuildings: If an outbuilding, like a shed or a garage, is less than 4 meters high and doesn’t take up more than half of the land around your home, you can build it without planning permission. Structures that exceed this size are likely to need permission, and you will need to contact your local authority.

How much can I extend my home without planning permission?

The rules surrounding home extensions are quite complicated, and there are many factors that go into determining whether or not you can build one without permission. The distance that you can extend your home will depend on the type of extension you are adding, along with the current state of your property.

  • The extension cannot exceed more than half of the area around your original home (after 1948).
  • The extension cannot be higher than the original roof.
  • Single-story extensions may not extend further than 8-meters away from the original back wall of the property.
  • Single-story extensions may not exceed a height of 4-meters.
  • Side extensions may not exceed more than half of the width of the original property.

If your extension breaks any of these rules, you will need to seek planning permission to carry it out. Alongside this, you also need to think about the way that your extension is built. If you plan to use materials that aren’t the same as the original property, you will need to get permission, and this is especially important for older properties.

Of course, though, this gives you a lot of freedom when it comes to building an extension. While it may be difficult to stay within these rules, you can still make a sizable extension without breaking them. Flats and apartments have different rules, and this is something to keep in mind if you own properties like this.

How far can you extend homes in conservation areas without planning permission?

Conservation areas were introduced in the 1960s as a way to preserve the architectural heritage of certain areas in Britain. With more than 10,000 of these areas, many people live in homes that come under different rules from the rest of those in the UK. If you live in an area like this, you will have to work harder to get an extension done.

  • All two-story extensions must have planning permission in conservation areas. 
  • Extensions may not go beyond the sidewall of property without planning permission in areas like this.
  • Any extensions to the side of a house in a conservation area must have planning permission.
  • Changes to roofs in conservation areas will usually require planning permission.

As you can see, it can be harder to build an extension when you live in a conservation area, but this is for good reason. Places like this have often remained largely unchanged for more than half a century, and it would disturb the character and feel of the place if homes drastically changed overnight.

It can feel strange to have to ask for permission when you want to build or add an extension to your home. A lot of people struggle with this process, finding it hard to know what they need to do when they want to add to their property. Thankfully, though, there are loads of guides and tools on the web that can help with a process like this.