Detective work

Some detective work has resulted in a planning inspector deciding that an extension to a house in Derbyshire would not be inappropriate development in the green belt (DCS Number 400-026-608).

The inspector recorded that Paragraph 145 of the Framework sets out a small number of exceptions to inappropriate development in the green belt. One such exception is the extension or alteration of a building, provided that it does not result in disproportionate additions over and above the size of the original building. Local plan policy, he noted, was broadly consistent with the Framework.

The council considered that, in most cases, an extension resulting in more than a 30 per cent increase in footprint and volume, compared to the original building, would be disproportionate. The dispute between the main parties concerned how much the building on the site had increased from its original size.

The inspector found no conclusive evidence on the ground that the cottage was originally joined to existing outbuildings. Nevertheless, he agreed that the OS 25-inch 1892-1914 map indicated that this had been so, showing an L-shaped building footprint joined to what was now approximately the main body of the cottage. The OS six-inch England and Wales 1842-1952 map and 1940s-1960s National Grid maps showed similar footprints.

Judging by the totality of historical map and existing layout plan evidence before him, he considered that the size of the footprint of the original building as a whole, including buildings joined to the main dwelling core as it stood on 1 July 1948, was in the region of no less than 170 sq.m. He also calculated that, even if an apparently demolished rectangular building which originally adjoined the current main body of the cottage was single storey, the volume of the original building was in the region of no less than 850 cu.m.

The inspector found that the proposal, for additional bathroom space with a shower, would not entail an increase in the size of footprint of the building, over and above that of the original, and would result in a combined increase in building volume of less than ten per cent over and above the original. Taking this together, he found that the proposal would not result in a disproportionate addition to the original building, and so would meet the exception test in paragraph 145c) of the Framework. Consequently, the proposal would not amount to inappropriate development in the green belt.

Information concerning house extensions in green belts can be found at section 12.632 of DCP Online.