Liz,
This isn't as clear cut as suggested by the legislation when you factor into a rise in the land.
I had thought what we were talking about here wasn't a permitted development, which involves giving the affected homeowners the chance to object, but an exempted development - isn't that the case?
If so, in relation to exempted development the provisions of the Planning and Development Regulations 2001 are as follows:
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CLASS 1
The extension of a house, by the construction or erection of an extension (including a conservatory) to the rear of the house or by the conversion for use as part of the house of any garage, store, shed or other similar structure attached to the rear or to the side of the house.
CONDITIONS AND REASONS
1. (a) Where the house has not been extended previously, the floor area of any such extension shall not exceed 40 square metres.
(b) Subject to paragraph (a), where the house is terraced or semi-detached, the floor area of any extension above ground level shall not exceed 12 square metres.
(c) Subject to paragraph (a), where the house is detached, the floor area of any extension above ground level shall not exceed 20 square metres.
2. (a) Where the house has been extended previously, the floor area of any such extension, taken together with the floor area of any previous extension or extensions constructed or erected after 1 October 1964, including those for which planning permission has been obtained, shall not exceed 40 square metres.
(b) Subject to paragraph (a), where the house is terraced or semi-detached and has been extended previously, the floor area of any extension above ground level taken together with the floor area of any previous extension or extensions above ground level constructed or erected after 1 October 1964, including those for which planning permission has been obtained, shall not exceed 12 square metres.
(c) Subject to paragraph (a), where the house is detached and has been extended previously, the floor area of any extension above ground level, taken together with the floor area of any previous extension or extensions above ground level constructed or erected after 1 October 1964, including those for which planning permission has been obtained, shall not exceed 20 square metres.
3. Any above ground floor extension shall be a distance of not less than 2 metres from any party boundary.
4. (a) Where the rear wall of the house does not include a gable, the height of the walls of any such extension shall not exceed the height of the rear wall of the house.
(b) Where the rear wall of the house includes a gable, the height of the walls of any such extension shall not exceed the height of the side walls of the house.
(c) The height of the highest part of the roof of any such extension shall not exceed, in the case of a flat roofed extension, the height of the eaves or parapet, as may be appropriate, or, in any other case, shall not exceed the height of the highest part of the roof of the dwelling.
5. The construction or erection of any such extension to the rear of the house shall not reduce the area of private open space, reserved exclusively for the use of the occupants of the house, to the rear of the house to less than 25 square metres.
6. (a) Any window proposed at ground level in any such extension shall not be less than 1 metre from the boundary it faces.
(b) Any window proposed above ground level in any such extension shall not be less than 11 metres from the boundary it faces.
(c) Where the house is detached and the floor area of the extension above ground level exceeds 12 square metres, any window proposed at above ground level shall not be less than 11 metres from the boundary it faces.
7. The roof of any extension shall not be used as a balcony or roof garden.
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As you can see the term used is "above ground level".
However the definition of this term in the regulations is misleading
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From:
S. 5 (2) In Schedule 2, unless the context otherwise requires, any reference to the height of a structure, plant or machinery shall be construed as a reference to its height when measured from ground level, and for that purpose “ground level” means the level of the ground immediately adjacent to the structure, plant or machinery or, where the level of the ground where it is situated or is to be situated is not uniform, the level of the lowest part of the ground adjacent to it.
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This definition is not applicable to "windows".
So, is the window on a sloping site "above ground level" or not?
There is obviously a case to be amde in terms of the degree or perceived overlooking.
If you feel there is an issue that the local authority can help you resolve - for example defining whether or not a breach of planning law has occurred - then contact the planning Enforcement Section and ask them to attend and inspect.
I'm sorry I cannot be of more help for now.
ONQ.
[broken link removed]
All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.