Loft conversion permitted development – loft conversions can be built within permitted development rights law

Permitted development – your right to develop your home

Since October 2008 a loft conversion is considered to be permitted development, not requiring an application for planning permission. Permission is required if you extend or alter the roof space and it exceeds specified limits and conditions. The permitted development limits and conditions are:

  • A volume allowance of 40 cubic metres additional roof space for terraced houses*

  • A volume allowance of 50 cubic metres additional roof space for detached and semi-detached houses*

  • No extension beyond the plane of the existing roof slope of the principal elevation that fronts the highway

  • No extension to be higher than the highest part of the roof

  • Materials to be similar in appearance to the existing house

  • No verandas, balconies or raised platforms

  • Side-facing windows to be obscure-glazed; any opening to be 1.7m above the floor

  • Roof extensions not to be permitted development in designated areas which include national parks and the Broads, areas of outstanding natural beauty, conservation areas and world heritage sites.

  • Roof extensions, apart from hip to gable ones, to be set back, as far as practicable, at least 20cm from the original eaves

  • The roof enlargement cannot overhang the outer face of the wall of the original house

These permitted development allowances apply to houses.

Visit the Planning Portal for more details on:

  • Flats and maisonettes

  • Converted houses or houses created through the permitted development rights to change use

  • Other buildings

  • Areas where there may be a planning condition, Article 4 Direction or other restriction that limits permitted development rights

* Please consider any previous roof space additions. They must be included within the volume allowances listed. Although you may not have created additional space a previous owner may have done so.

For more help please visit the interactive loft conversions mini guide on the government planning portal

Visit the interactive loft conversions guide