Single and double storey extensions guidelines

When beginning a project, you must consider whether the development will need to have planning permission or building regulations approval or your project may need both. These are two separate applications and must be applied for individually by ourselves.We work closely with a local Building Control office who we would always suggest to use but your free to instruct who you wish. For planning permission we can apply for you offering a start to finish service taking all the stress of planning away from you. Most planning and building control applications are now submitted online. To view the planning portals application page please click here.

You’ll probably need planning permission if you want to:

• Build something new to your existing building or on a plot of land.
• Make a major change to your existing building, eg building an extension.
• Change the use of your building.

If your project needs planning permission and you do the work without getting it, you can be served an ‘enforcement notice’ ordering you to undo all the changes you have made.
We would never start any works without planning permission being granted prior to the works to avoid any enforcement’s that could be served in the future.

Some extensions are considered to be permitted development, not requiring an application for planning permission, subject to the following limits and conditions:

• No more than half the area of land around the “original house”* would be covered by additions or other buildings.
• No extension forward of the principal elevation or side elevation fronting a highway.
• No extension to be higher than the highest part of the roof.
• Single-storey rear extension must not extend beyond the rear wall of the original house* by more than three metres if an attached house or by four metres if a detached house.
• In addition, outside Article 2(3) designated land* and Sites of Special Scientific Interest the limit is increased to 6m if an attached house and 8m if a detached house until 30 May 2019.
• These increased limits (between 3m and 6m and between 4m and 8m respectively) are subject to the prior notification of the proposal to the Local Planning Authority and the implementation of a neighbour consultation scheme. If objections are received, the proposal might not be allowed.
• Maximum height of a single-storey rear extension of four metres.
• Extensions of more than one storey must not extend beyond the rear wall of the original house* by more than three metres.
• Maximum eaves height of an extension within two metres of the boundary of three metres.
• Maximum eaves and ridge height of extension no higher than existing house.
• Side extensions to be single storey with maximum height of four metres and width no more than half that of the original house.
• Two-storey extensions no closer than seven metres to rear boundary.
• Roof pitch of extensions higher than one storey to match existing house.
• Materials to be similar in appearance to the existing house.
• No verandas, balconies or raised platforms.
• Upper-floor, side-facing windows to be obscure-glazed; any opening to be 1.7m above the floor.
• On designated land* no permitted development for rear extensions of more than one storey.
• On designated land no cladding of the exterior.
• On designated land no side extensions.

* The term “original house” means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date). Although you may not have built an extension to the house, a previous owner may have done so.

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