The appellants claimed that the works fell within either class B or class C of part 1, schedule 2 of the General Permitted Development Order 1995 as amended. Since the terms "additions" and "alterations" in those classes are not defined, they maintained that it was a matter of fact and degree whether the extent of the works fell in either class. Since a substantial part of the existing roof would be retained, they claimed that a rear dormer would not require specific permission.
The inspector agreed that the two terms are not defined in the order, so whether particular works constitute alterations is a matter of fact and degree. The courts have held that a similar approach should be followed in assessing whether works involve an addition to a roof rather than a complete replacement, he noted.
The property had a double-hipped roof that would have its ridge lowered to comprise a single gable. A dormer would be inserted into the slope. While it might be possible to reuse timbers and other materials, the inspector considered that the changes involved a complete demolition and rebuilding of the roof. On this basis, he held that the works could not fall in class B or C.
DCS Number 100-069-244
Inspector Colin Thompson; Written representations