Appeal 3309645

The appeal is allowed and planning permission is granted for single-storey rear extension at Ashley, [site address] , [site address] [postcode] in accordance with the terms of the application, Ref 22/02227/FUL, dated 6 June 2022, subject to the following conditions:

The development hereby permitted shall begin not later than 3 years from the date of this decision.

The development hereby permitted shall be carried out in accordance with the following approved plans: 01 [name]; 02 [name].

The main issue is whether the proposal would be inappropriate development in the Green Belt, having regard to the National Planning Policy Framework (the Framework) and any relevant development plan policies.

The appeal property is an extended two-storey detached house located among a linear group of houses on the south side of [site address] , and is identified as being within the Green Belt.

Paragraph 149 of the Framework states that the construction of new buildings should be regarded as inappropriate in the Green Belt, unless it falls within a number of listed exceptions. These include 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. Policy GS4 of the Harrogate District Local Plan (2020) (the LP) does not repeat the Framework exceptions, but identifies that applications for development in the Green Belt will be determined in accordance with national policy.

Neither the Framework nor LP Policy GS4 define what would constitute a disproportionate addition. [address] Extensions & Garages Design Guide Supplementary Planning Document (2005) (SPD) advises that extensions in the Green Belt should not increase the ground floor area of the original house by 50%. However, the Framework refers to ‘size’ rather than footprint, and I note that the Council did not seek to rely on the SPD in its assessment. I have therefore treated the SPD threshold as no more than a guide.

It is common ground that the proposed extension, when taken with previous additions, would result in a floor area increase of 144% and a volume increase of 156% over the size of the original building. In purely mathematical terms this sounds potentially disproportionate, and far exceeds the SPD guidance. Indeed, in some circumstances, a percentage increase of this scale might be sufficient in itself to constitute a disproportionate addition over and above the size of an original building in the terms of the Framework. That said, when determining whether or not a proposal would be a disproportionate addition, it is also important to consider the visual increase in the size of the original building, taking into account the nature of the site and the precise nature of the proposal. This is a matter of planning judgement for the decision maker.

In this instance, the proposal is for a single-storey extension at the rear, and is partly a replacement for the single-storey lean-to extension that already exists. It would be wider, but no deeper than the existing extension and would not extend past the side elevation. At just 7.5m2 of additional floor space and 19.3m3 of additional volume, it represents only a small addition to the total floorspace and volume of the two-storey dwelling, and effectively amounts to an infill of a small corner at the back of the house. Indeed, the Council had no objection in design terms and refer to the proposal as a relatively modest addition. Thus, even when considered cumulatively with previous additions, the proposed extension would appear subservient and would integrate well with the existing building. In addition, due to its location at the rear and the screening from the existing and neighbouring buildings, as well as mature boundary vegetation, the extension would not be readily visible from public viewpoints.

Taking all these factors into account, it is my judgement that the proposed extension would not be a disproportionate addition over and above the size of the original building. I therefore conclude that the proposal would not be inappropriate development in the Green Belt, and to this extent, it would not conflict with the Green Belt protection objectives of the Framework and LP Policy GS4. Where development is not inappropriate, it goes without saying that it would not be harmful to the openness of the Green Belt and would not conflict with any of the purposes for including land within it.

As suggested by the Council I have imposed the standard commencement and approved plans conditions for certainty. However, a condition requiring matching external materials is not necessary because the materials are already specified on the plans.

Subject to these conditions, and for the reasons given, I conclude that the appeal should succeed.