Paragraph B.1 Development not permitted
Development is not permitted by Class B if—
any part of the dwellinghouse would, as a result of the works, exceed the height of the highest part of the existing roof;
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;
any part of the dwellinghouse would, as a result of the works, extend beyond the plane of any existing roof slope which—
is comprised in a side elevation of the existing dwellinghouse; and
is within 10.5 metres from a highway opposite the side elevation of the dwellinghouse;
the cubic content of the resulting roof space would exceed the cubic content of the original roof space by more than—
40 cubic metres in the case of a terrace house; or
50 cubic metres in any other case;
other than in the case of a hip to gable enlargement, any part of the enlargement would be less than 20 centimetres from the eaves of the existing roof;
it would consist of or include—
the construction or provision of a veranda or raised platform ;
the construction or provision of a balcony which—
contains a platform of any description;
projects from the part of the exterior of the dwellinghouse to which it is affixed by more than 30 centimetres; or
if projected downwards in a vertical line to ground level, is within 10.5 metres of any boundary of the curtilage of the dwellinghouse opposite the relevant side elevation; or
the construction or provision of a roof terrace, whether or not it would incorporate associated railings, fencing or other means of enclosure; or
the dwellinghouse is on article 1(5) land or within a World Heritage Site.