At the time of the appeal, the two-storey end-of-terrace house had been enlarged by way of a full-width single-storey rear extension and a rear dormer window, involving the replacement of the hipped roof with a gable end. The council accepted that, by themselves, the dormer and roof enlargement would have been permitted development under class B, part 1, schedule 2 of the General Permitted Development Order (GPDO) 1995.
However, its case was that the rear extension had been substantially completed at the time the dormer and roof extension were also substantially completed. As a result, it claimed that the permitted development tolerance which might otherwise have been available for the loft conversion had been displaced.
The inspector decided that the evidence suggested that the side walls of the rear extension had been in place when the loft conversion was substantially completed. He referred to the case of R ex parte Watts v Secretary of State for the Environment, Transport and the Regions (2002), in which the court pointed to an inherent degree of artificiality in the GPDO in that its application depends on which works are done first.
The inspector reasoned that if, between the start of the loft conversion and its substantial completion the building had been so enlarged that its resultant cubic content with the loft conversion exceeded the GPDO allowance, then the loft conversion would lose the protection of the GPDO.
He asserted that it was a matter of judgement at what point any enlargement or alteration had a cubic content but that prospective cubic content, however imminent, should be ignored.
He held that in order to count against the cubic capacity tolerances, the development concerned must have had the effect of enclosing some space.
He found that the lack of side walls, a roof covering and a floor meant collectively that the cubic content of the resulting building remained prospective at the relevant time. Accordingly, he concluded that the ground-floor works should be disregarded in assessing the cubic content of the resulting building in calculating the class B allowance.
DCS No: 34216535; Inspector: Rod Evans; Written representations.