Roof lights in Side extension (permitted development)

This information is correct, in addition to this you must not be able to open it unless it has a cill height of 1.7 Metres measured from the finished floor level of the room in which it has been fitted. There is no reason as to why frosted glass would not allow adequate light into the room. Please note that obscure plastic sheeting being fitted to clear glass would not be acceptable to the Planning Department. I hope this answers your question.

This information is correct, if you require validation then go to (https://www.gov.uk/government/publications/permitted-development-rights-for-householders-technical-guidance) and download : Permitted development rights for householders: technical guidance. on Page 37,38 you will find ; (c) any window inserted on a wall or roof slope forming a side elevation of the dwellinghouse shall be - (i) obscure-glazed, and (ii) non-opening unless the parts of the window which can be opened are more than 1.7 metres above the floor of the room in which the window is installed Windows for a loft extension on a side elevation of a house must be obscure glazed to benefit from permitted development. Glazing to provide privacy is normally rated on a scale of 1-5, with 5 providing the most privacy. To be permitted development, side 38 windows should be obscure glazed to minimum of level 3. Obscure glazed does not include one-way glass. Where such a window is on a staircase or landing (ie not in a room) the 1.7 metres measurement should be made from the stair or point on a landing immediately below the centre of the window, upwards to the opening part of the window (see diagram under Class A - A.3 (b) above).