Extending your home without planning permission; understanding permitted development rights


Every year, thousands of people look to add living space and increase the re-sale value of their homes by renovating them. Some extensions can be carried out in England under ‘permitted development rights’ rules. Find out more.

The basics of permitted development rights

Permitted development rights mean, as the name implies, that you’re allowed to extend your property within certain limits without having to apply to the local authority for planning permission. The rules changed in 2014 and since then you’ve been able to extend your property as long as:

1. The extension and any outbuildings don’t cover more than 50% of the land the property stands on, excluding the original house.

SAVVY TIP: The ‘original’ house is described as the property in its original form on 1st July 1948, if it was built before then, or as it was originally built, it it was built after that date.

2. The extended property isn’t any taller than the highest part before it was extended.

SAVVY TIP: When working out the height of the original property, you should use the roof ridge (if it’s a sloping roof) or the highest roof if the roof is flat. You should ignore chimneys etc.

3. The height of the eaves of the extended property aren’t higher than the eaves of the original property. The eaves are the point where the lowest part of the roof meets the wall.

4. The extension does not extend the front of the property beyond or the side of the property if a road runs alongside the front of it.

5.  Any single storey extension is not more than four metres long if it’s a detached house, or three metres long for all other types of property. In either case it can’t be more than four metres tall.

SAVVY TIP: Until 30th May 2019, single storey extensions can be up to eight metres in length for detached houses or six metres for all other properties (but still only four metres tall) as long as the property is not on a site of special scientific interest.

6. Any extension within two metres of the boundary is not more than three metres tall.

Side and rear wall extensions

There are a number of rules covering side and rear wall extensions. For example, if the extension is both a side and rear wall extension, it should not be wider than half the width of the original property. If it’s just a side wall extension, it can only extend for three metres beyond the rear wall (or six metres, up until 30th May 2019). You can find all the rules governing side and rear extensions on the Gov.uk website (there’s a link to some information at the end of this article).

What’s not covered by permitted development rights

There are certain types of property and certain areas that are not covered by permitted development rights. Scotland, Wales and Northern Ireland have their own versions of permitted development rights.

  • Flats and maisonettes etc are not covered by permitted development rights. The permitted development rights which apply to many common projects for houses do not necessarily apply to flats, maisonettes or other buildings.
  • Conservation areas are not covered. There are different requirements for conservation areas. You can find information about extending your property in a conservation area on the Gov.uk website.

Permitted development rights and building regulations
Permitted development rights allow you to do things that simply wouldn’t be possible through the full planning process.

SAVVY TIP: Permitted development rights are a great way to speed up the upfront process, but they’re not a means of cutting corners once the project gets underway. Building regulations approval is needed for most building work done in the UK.

  • The building regulations are grouped into different categories (covering everything from structure – category A to electrical – category P). The Planning Portal has information about building regulations, which are there to make sure that buildings are safe and use energy and water efficiently.
  • Whoever carries out the building work should be responsible for ensuring that the work is compliant with the building regulations. Responsibility ultimately lies with the building owner though, who may be served a notice if work doesn’t comply with the building regulations.

SAVVY TIP: The main function of Building Control is to ensure that the building regulations are complied with. Building work as defined in the building regulations will normally need approval from a Building Control Body. You can find information about the type of building work requiring approval from the government’s Planning Portal website.

Has your home already been extended?
If you bought your home many years after it was built you may be unsure how to find out if it’s already been extended or changed from its initial design. If permitted development rights have already been used they won’t necessarily be documented with your local council’s planning department.

1. To check, have a look at the ownership deeds. These should include the original floorplans. Knowing the history of your home and how it has evolved may help you decide how to change it for the best to make it your own.

2. Get expert opinion. Do this if you’re concerned about determining the best route to help you assess the cost versus benefit of different options.

Related articles:

Can home staging help you sell your home for more?

5 things to look for in an offset mortgage

You can earn up to £7,500 a year tax free using the ‘rent-a-room’ scheme to take in a lodger

Useful links:
The government’s gov.uk website has detailed and technical guidance and information about permitted development rights

SavvyWoman email newsletters: If you found this information useful why not sign up now to receive free fortnightly email newsletters with money saving tips and help? You can sign up at the top of any page on the website and your details won’t be passed to any other company for marketing purposes.