You can extend or ad to your house without the need to apply for planning permission provided you meet a new set of limits and conditions that came into force in 1st October 2008 – sometimes referred to as permitted development rights.
 
An extension or addition to your house is 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.
 •Maximum depth of a single-storey rear extension of three metres beyond the rear wall for an attached house and four metres beyond the rear wall for a detached house.
 •Maximum height of a single-storey rear extension of four metres.
 •Maximum depth of a rear extension of more than one storey of three metres beyond the rear wall including ground floor.
 •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.
 
* Designated land includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Site.