A loft conversion for your house is considered to be permitted development, not requiring an application for planning permission, provided certain limits and conditions are met.
- Loft conversions are NOT permitted development for houses on designated land*.
- To be permitted development any additional roof space created must not exceed these volume allowances:
- 40 cubic meters for terraced houses.
- 50 cubic metres for detached and semi-detached houses. Bear in mind that any previous roof space addition must be included within this volume allowance. Although you may not have created additional space a previous owner may have done so.
- An extension beyond the plane of the existing roof slope of the principal elevation that fronts a highway is NOT permitted development.
- Materials to be similar in appearance to the existing house.
- No part of the extension to be higher than the highest part of the existing roof
- Verandas, balconies or raised platforms are NOT permitted development.
- Any side-facing windows must be obscure-glazed and non-opening unless the parts which can be opened are more than 1.7 metres above the floor of the room in which it is installed.
- Roof extensions, apart from hip to gable (hip-loft), are to be set back, as far as is practicable, at least 20cm from the original eaves. The 20cm distance is measured along the roof plane.
- Work on a loft or a roof may affect bats. You need to consider the protected species when planning work of this type. A survey may be needed, and if bats are using the building, a licence may be required.
*Designated land includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.
For a more in-depth guide to the planning regulation for loft conversions please visit The Planning Portal.
Please note: the permitted development allowances described here apply to houses not flats, maisonettes or other buildings.