Whether you’re staying put, or have just moved in to your new pad, plenty of homeowners are asking themselves: how much can I extend my house without planning permission. 

The government, keen to stimulate the building and architecture economy, has relaxed rules around this to reduce paperwork for something that is generally quite straightforward, given you stick to certain rules. 

Extending your house without planning permission: the basics

Under permitted development rules you can build an extension up to six metres  – or eight if your house is detached. There are, however, other conditions. 

  • No more than 50% of the land around the house can be covered by other buildings
  • No extensions jutting forward from the front of the house, or from the side in front of an highway.
  • The extension can’t be higher than the top of your roof
  • A single storey extension cannot extend beyond the rear wall of the original building by more than six metres (eight metres if the house is detached).
  • Note: Prior Approval applies to larger extensions, i.e. between four and eight metres on detached houses, three and six metres on other types.
  • The maximum height of a single storey extension is four metres.
  • Double storey extensions more than one storey cannot extend from the rear wall of the house by more than three metres, and cannot come within seven metres of the rear boundary of the plot.
  • No balconies, verandas or raised platforms.

How much can I build with a side extension?

Under Permitted Development Rules, a side extension:

  • Cannot measure more than half the existing width of the house
  • Cannot extend more than three metres from the original house
  • Must not front onto a road.
Single-storey extension in Harborne

How much can I extend with a rear extension?

For single storey rear extensions, Permitted Development Rules allow you to:

  • Extend up to eight metres for detached homes, or,
  • Six metres for for all other types of houses. 

For extensions that are over four metres you will have to notify your neighbours and if they object, you may not be able to build an extension this large.

Do I need planning permission for a side return extension?

Side return extensions are really common in towns and cities, and are generally extend more than three metres from the back of the house, as such, you’ll have to seek prior approval for your side return extension under the Neighbour Consultation Scheme – more on this down below. 

A common result of this is that the side return extension has to respect the height of the boundary wall so that your neighbour doesn’t suffer any loss of light, so sloped rooves are often common with side return extensions.

What about double storey extensions?

Under the new Permitted Development Rules, double storey extensions may extend up to three metres from the original house.

In addition, they cannot be within seven metres of the rear boundary of your plot. 

In terms of architects, the shape of the roof must match the existing home, and the side facing windows must be above 1.7 metres above the floor.

Can my neighbours object to my extension?

Although the new larger home extension scheme is undoubtedly generous, your neighbours do have the right to object to this.

If your extension measures over three metres – for terraced/semi-detached houses – or four metres – if it’s detached – then you have to seek Prior Approval under the Neighbour Consultation Scheme.

The council will notify your neighbours, and they have a 21 day period in which they can give valid reasons as to why they believe the extension should not be built.

The local authority then has a further 21 days to grant this Prior Approval under the Consultation Scheme, at which point a fee will be payable for a Lawful Development Certificate – which is a great idea anyway – and takes eight weeks to receive a decision.

Remember this only applied to the larger extensions over three metres, or four if it’s detached. 

Expert extension advice from Lapworth Architects

Depending on whether you’re looking for a side, rear, single or double storey or even a side return extension – size and neighbours are the main consideration when it comes to how much you can extend your house by without planning permission. Remember, that Lapworth Architects are experts in this area, and can help you with your design and planning needs. Give us a call to set up your free consultation, and see how we can design you all the space you need!

Call us on 0121 455 0032 today to book your
FREE consultation

We are award-winning architects working across the entire West Midlands to help you at every step of the process, whether you’re needing an extension, developing land or designing a new build house.

– Birmingham
– Bromsgrove
– Edgbaston
– Leamington
– Solihull

– Stratford-on-Avon
– Sutton Coldfield
– Walsall
– Warwick
– Wolverhampton

abid shah
abid shah
13:03 17 Sep 20
Lapworth Architects provided me with a excellent service, which was responsive, high quality, professional and dealt... with the council on my behalf. I would strongly recommend them.read more
10:56 23 May 20
I contacted lapworth to carry out a site survey for a self build. I got great advice and a very fast turn around of my... report. We will definitely be using lapworth again for our designs.read more
nibha hegde
nibha hegde
19:51 20 Apr 20
I am extremely pleased with Lapworth architects. I just told them in my amateur way what I imagined or wanted in my... bungalow and they drew lovely accurate plans. Michael patiently took on board my multiple requests to make changes as new ideas came to me and he always incorporated them with even further development which shows his expertise. Michael provided monthly supervision service which I think is priceless and is the best part of hiring him!. He visited the site regularly, liaised with various other professionals involved like building control people, engineers, etc, did trouble shooting promptly, ensured costing is kept to minimum, and made sure the work is being carried out to the highest standards in a timely manner. The contractors and builders have also found this service very useful because of helpful professional advise and on-site discussions. I have noted from his late night/weekend emails/calls that Michael has worked very hard on my project- which was a total makeover of a rather dilapidated-closed- space building with poor lighting and access- and made it into a well lit, open spaced bright modern bungalow. He has always kept me well informed. Lastly, I have to say, because of his dedication, the project has carried on with practically no stress or worries imparted to me! He is well connected and tendered my project to a very good builder- for which `I am grateful. I sometimes hear other friends' stories of 'nightmare building projects' and I secretly thank my stars that I gave this project to Lapworth. I wish Michael and his team well. If I were lucky enough to acquire another property, I will promptly give the project to Lapworth again! :)read more
Hugh Humphreys
Hugh Humphreys
23:23 19 Feb 20
Did a very competent job with good value for money, understood my needs and produced the drawings for a complex... extension quickly. Made the small changes requested and continued to provide support on detail on request. I would use them again on further projectsread more
Kay Bedi
Kay Bedi
16:54 01 Feb 20
I used Lapworth after using two different architects who were unable to secure planning permission due to lack of... knowledge in relation to green belt policy and lack of expertise in relation to producing reports alongside planning applications. Ultimately these were the two things that were required to get out planning application approved and we were impressed with the knowledge, expertise and professionalism of everyone we had interactions with at the firm. The firm is better value for money than others we have used as they provide better quality of service at the same price. I would definitely use them again and would recommend them. The staff have a great attitude and work hard to get you the outcome you want. We finally got our application approved and if we had come to Lapworth to start with we would not have wasted two years and a considerable amount of money trying to get planning approved. Thanks to all at Lapworth, particularly Tristan and Tumi for working so hard and providing a great customer service and quality work also thank you to Mike for the great service he has provided. Kayread more
Colin Andrews
Colin Andrews
16:25 15 Jan 20
I can honestly say I don't give reviews, but on this occasion I felt I must. Michael Singh of Lapworth Architects spoke... on behalf of my Company's planning application at Walsall Planning committee for an Adventure Golf Course situated in the Green Belt. The application was submitted in February 2018 and at last came before committee with over 40 objections from residents. Michael Singh spoke on my behalf and obviously new his stuff. He showed he cared about this application. His passion caused others to be convinced not just because of his force of reasoning, but also because he was visibly enjoying the beliefs he wanted the committee to accept. Michael Singh won over the committee members through his professional manner. Accurate, competent, credible, intelligent, knowledgeable, likeable, and believable. The committee voted in favour and gave planning approval. I highly recommend Lapworth Architect's. I definitely will use them again. Thank you so much Michael you were just BRILLIANT Regards Colin Andrews Directorread more
Rajashankar rao
Rajashankar rao
09:53 18 Feb 19
We ( me and my wife) would definitely recommend Lapworth architects without any hesitation.They have been professional... and very prompt in answering our issues. They have been efficient in getting the plans we desired and did the whole application from scratch without any delays. We personally had Manraj to look into our case and absolutely none issues. He has been very efficient in chasing the application process along with updates and infact, got the application approved without any changes.read more
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