Permitted Development

If you’re in the UK and you’re planning your next building project, you might be surprised to discover that you may not require planning permission. Here in the UK, we have what are known as ‘permitted development rights,’ legally allowing you to build developments such as extensions on your property without applying for planning permission, but these do come with some exceptions.

Related: When is permission required? 


Before you get too excited, there is one major exception. These rules only apply to houses, so if you live in a flat or a maisonette it’s time to stop this party. Sorry folks. If you’re a homeowner, however, read on and find out what you can do.

Another major exception that may interfere with your project is whether or not you live in a ‘designated area.’ In these areas permitted development rights are restricted. Designated areas include the following:

  • National Parks and Broads
  • World Heritage Sites
  • Conservation Sites
  • Areas of Outstanding Natural Beauty

Under permitted development, you can build both one and two-storey extensions on your property. Keep in mind they have slightly different rules.

Related: The Town and Country Planning (General Permitted Development) (England) Order 2015


Your development is permitted to cover up to 50% of the land surrounded by the ‘original house.’ This includes any area taken up by any additional outbuildings, including sheds, so remember to calculate these when planning your project. It is also important to make note that if the building work adds up to over 100m2 it could be liable for a charge under the Community Infrastructure Levy.

Related: About the Community Infrastructure Levy


The term ‘original house’ means the house as it was first built, or how the house was on July 1st 1948 if the property is older than that. 

If the previous owners of the property have already built an extension, what you can build will be limited as the land they have built on will not count as the original house.

To adhere to the rules, source materials for your development that resemble that of the materials used for the existing house.

Permitted development is particular on where you can build extensions on your property and their dimensions. For example, any extension you are planning cannot have a width longer than 50% of the width of the original house. Any extension reaching further than the front of the house, facing the road, will not be permitted. Extensions cannot reach higher than the highest part of the roof, while side extensions are limited to a height of 4 metres.

For most houses, a single-storey rear extension can extend up to 6 metres beyond the rear wall of the house, and 8 metres for detached houses. This is slightly different for two-storey rear extensions as they must not extend beyond the rear wall of the original house by more than 3 metres and cannot be within 7 metres of any boundary opposite the rear wall. These rules are more restrictive for designated areas; extensions being limited to 4 metres for detached houses and 3 metres for any other type of house.

You can build your dream extension without interference as long as you follow the rules. Remember, if you’re a homeowner, you probably don’t need to ask for permission.

Related: Planning Permission


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