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.
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!
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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.
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