Planning permission is usually required unless the parameter of Permitted development can be met, details below, there are some minor exceptions. Flats are excluded, and if the property is a conservation area, is listed or in an area of outstanding natural beauty.
A loft conversion is considered to be a permitted development if the following conditions are met:
- There is a volume allowance of 40 cubic metres added roof space for terraced houses
- There is a volume allowance of 50 cubic metres added 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 is permitted
- The new materials like tiles, to be similar in appearance to the existing house
- There are no verandas, balconies or raised platforms or terraces
- Side-facing windows to be obscure-glazed; any opening to be 1.7m above the internal floor
- Roof extensions not to be permitted development in designated areas
- Roof extensions, apart from hip to gable ones, to be set back, as far as practicable, at least 20omm from the original eaves
- Roof enlargement cannot overhang the outer face of the wall of the original house.