Extensions

Since October 2008, you can build an extension without planning permission as long as the following parameters are met.

1. No more than half of the land surrounding the original house* should be covered by additions or other buildings.
2. Your extension should not be higher than the highest part of your property's roof.
3. If your extension is to be built at the rear and is one storey high, it must have a maximum depth of three metres for an attached house and four metres for a detached house. Measure the depth from the rear wall of your property.
4. The maximum height of your extension at the rear should be four metres.
5. If you're planning to build an extension of more than one storey, the maximum depth to go for is three metres from the rear wall of your property and including the ground floor.
6. The maximum eaves height of your extension should be 3 metres when it's built within 2 metres of your property's boundaries.
7. The maximum eaves and ridge height of your extension should be no higher than your existing property.
8. If you plan to build an extension on the side of your home, without planning permission you should opt for a single storey extension with a maximum height of four metres and with a width of no more than half that of your existing property.
9. Any two storey extension you are planning should reach no further than seven metres to the rear boundary of your property.
10. The roof pitch on any extension higher than one storey should match the pitch of your existing home.
11. Without planning permission, you should opt for an extension built with similar materials and a similar appearance to your existing home.
12. Your extension should not have any verandas, balconies or raised platforms.
13. If you are planning to build in upper floor or side-facing windows, they should be obscure-glazed and any opening of this kind should be 1.7m above the floor.
14. On designated land*, you will have to apply for planning permission if you plan to build an extension of more than one storey in height, intend to clad the exterior of your extension or want a side extension.

* Designated land includes the Broads, national parks, World Heritage Sites, conservation areas and Areas of Outstanding Natural Beauty.

Source: planningportal.gov.uk

You need to apply for planning permission to extend or add to your house in the following circumstances:

• You want to build an extension which would be nearer to any highway than the nearest part of the original house unless there would be at least 20 metres between your house (when extended) and the highway. The term 'highway' includes all public roads, public footpaths, bridleways and byways.
• More than half of the area of land surrounding the original house would be covered by extensions or other buildings.

The term 'original house' means the house as it was first built, or as it stood on 1st July 1948 if it was built before that date. (You may not have built an extension, but the previous owners may have).

If none of the above rules apply to your proposed extension you may need to check the height and volume limits. You'll need permission if:

• The extension is higher than the highest part of the roof of the original house, or any part of the extension is more than 4 metres high and is within 2 metres of the boundary of your property (loft conversions and dormers have separate rules).
• For a terraced house, including an end of terrace, or any house in a Conservation area or Area of Outstanding Natural Beauty: the volume of the original house would be increased by more than 10% or 50 cubic metres, whichever is the greater. For any other kind of house: the volume of the original house would be increased by more than 15% or 70 cubic metres, whichever is the greater. In all cases: if the volume of the original house would be increased by more than 115 cubic metres.

In the following circumstances the volume of other buildings, which belong to your house (garage, shed etc.) will count against the volume allowance. In some cases this can include buildings which were built at the same time as the house or existed on 1st July 1948:

• If an extension comes within 5 metres of another building belonging to your house, the volume of that building counts against the allowance for additions and extensions.
• Any building which has been added to your property and which is more than 10 cubic metres in volume and which is within 5 meters of your house, is treated as an extension of the house and so reduces the allowance for further extensions.
• If you live in a Conservation Area or Area of outstanding Natural Beauty all additional buildings which are more than 10 cubic metres in volume wherever they are in relation to the house are treated as extensions to the house and reduce the allowance for further extensions.