Hip to gable roof extension on a corner plot...

29 Aug 2015
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United Kingdom
...can this be done under permitted development?

My reading of the April 2014 technical guidance is that this can be done under class B. The property is a bay fronted semi on a main road, so what constitutes the principal elevation (red line) is clear.

The technical guidances states:

B.1 Development is not permitted by Class B if -
(b) any part of the dwellinghouse would, as a result of the works, extend beyond the plane of any existing roof slope which forms the principal elevation of the dwellinghouse and fronts a highway.

As I'm not extending the principal elevation, this is permitted development, even though I am extending towards a highway. Have I got this right?
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You also need to consider where the main entrance to the house is and the windows on the side of the house. If the main entrance is on the side and there is a habitable room with a window to the side (as is sometimes the case with corner plot houses) then the principle elevation can be in doubt. On the other hand, if the main entrance is on the same elevation as the bay window then it's pretty clear which is the principal elevation.
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My local fire department has a principle fire officer, and my local plannning department has a principle planning officer. So how come there are so many unprincipled people wandering about?

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