Permitted Development changes allow for larger single storey extensions
The government has recently confirmed changes to permitted development to allow larger single storey extensions. For a period of 3 years, between 30th May 2013 and 30th May 2016, householders are able to build larger single storey rear extensions under permitted development; 8m depth for detached properties and 6m for terraced/semi-detached. Permitted development only applies if the property isn't listed or in a conservation area and there are various criteria (e.g. width relative to existing house, and height of extension). Guidance notes can be found here.