You will need planning permission for:

• Extensions fronting a highway on the principal elevation
• Any side extensions
• Rear extensions greater than one storey
• Cladding the exterior of the house
• Verandas and balconies
• Dormer windows
• Raised platforms more than 300mm high

Other developments may be permitted if the following conditions are met:

• The height of the eaves of the extensions must not exceed three metres if the extension is within two metres of a boundary
• Single-storey rear extensions must not extend from the wall of the original house by more than three metres for terraced or semi-detached houses, or four metres for detached houses
• The extension cannot be higher than 4 metres to the ridge line
• Materials must be of a similar appearance to existing materials
• Upper floor windows inserted in side elevations must be obscure glazed and open-able parts of the window must be more than 1.7 metres above the floor
• Total ground area covered by buildings in the curtilage must not exceed 50 per cent of the curtilage area