Appeal 3302959

The appeal is dismissed.

The main issues in this appeal are: • whether the proposal is inappropriate development in the Green Belt, having regard to local and national planning policy; • if it is inappropriate development, its effect on the openness of the Green Belt; and • whether any harm by reason of inappropriateness, or any other harm, is clearly outweighed by other considerations so as to amount to very special circumstances required to justify the proposal.

Under the Council’s Local Plan1 (the LP) saved policy GB1(e) permission will be granted for the limited extension of existing dwellings in the Green Belt. This is, amongst other things, subject to LP saved policy GB10(b) which sets out that the extension, together with any earlier extensions, must be small scale in relation to the size of the original dwelling.

The LP is broadly consistent with the National Planning Policy Framework (the Framework) in these regards, albeit that it does not reflect the precise wording of the exception at Framework paragraph 149 c); namely, that the extension of a building in the Green Belt should be regarded as inappropriate development unless it does not result in disproportionate additions over and above the size of the original building. The Framework does not refer to ‘limited extension’ or ‘small scale’. I have taken these matters into account in my

The existing dwelling, [address], is a replacement dwelling in the Green Belt settlement of Denham. It initially had roughly the same floorspace as the original dwelling but was subsequently enlarged by several extensions.

According to the Council’s calculations, which are not disputed by the appellant, those extensions cumulatively increased floorspace over and above the original dwelling by some 186m2 or 60%. This percentage increase was, though, in line with the Council’s convention for dwellings in Green Belt settlements. This is to permit extensions that are ‘a little larger’ than it regards as small scale for the purposes of LP saved policy GB10(b); which in the explanatory text otherwise means up to a 50% increase in floorspace compared to the original dwelling.

The Council’s calculations indicate that the proposed extension would enlarge the existing dwelling by about 67.32m2 or 21.7%. However, against the original dwelling, the overall enlargement would be approximately 253.32m2 or 81.9%. This would be a significant absolute and percentage increase beyond even the Council’s usual concession for extensions to dwellings in Green Belt settlements.

In addition, and though single storey, the extension would be wide and long. It would project much further behind the dwelling in-depth and stretch across a large proportion of the rear elevation. This would significantly increase the size of the external envelope and floorspace of the existing dwelling. A parapet wall around a flat roof would make all three elevations tall and a large central glazed roof lantern would protrude further above the parapet.

The proposal would not, therefore, be a limited extension or small scale in relation to the size of the original dwelling. As a result, it does not comply with LP policies GB1(e) or GB10(b). Furthermore, this disproportionate addition over and above the size of the original building conflicts with Framework paragraph 149 c). Accordingly, I find that the proposal would be inappropriate development in the Green Belt.

The extension would be sited over one end of a large patio, which is at ground level and largely innately open. In contrast, the extension would establish additional built form on the site with appreciable vertical height and overall scale and massing where there is none at present. It would be located behind the dwelling, away from nearby roads, and screened by tall, thick back garden boundary planting with little or no meaningful visual presence beyond the site. It would, though, have a significant permanent spatial presence.

The extension would be attached to the dwelling but the rest of the large rear garden is undeveloped and open. It would also roughly align with the rear elevation of the adjoining dwelling to the south. However, the part of the site for the extension would no longer be open in any equivalent or comparative sense to its existing condition, nor would it remain unchanged. This would result in a further spread of development on the site and, albeit a small loss, reduce the openness of the Green Belt which is one of its essential characteristics.

I find that the proposal is therefore at odds with the Council’s objectives for LP saved policies GB1(e) and GB10(b). These include to avoid harm to interests of acknowledged importance in the Green Belt and not compromise the overriding aim of the Green Belt. It also conflicts with Framework paragraph 137 and a fundamental aim of Green Belt policy to keep land in the Green Belt permanently open.

The appellant suggests that the extension would be permitted development but that the Council refused to grant prior approval because permitted development rights (PDR) have been removed at [address] by a condition attached to a previous planning permission. Moreover, that neighbouring dwellings have intact PDR. This has not been substantiated with any objective evidence and is not listed in the planning history or elsewhere referred to in the Council’s officer report. I have also not been informed whether any of these other dwellings have been previously extended or enlarged by replacement so I do not know if they are comparable in respect of PDR. I am not, therefore, satisfied that the appellant has demonstrated or justified these matters beyond speculation or assertion. In these circumstances there is no real prospect of a PDR fallback position. Consequently, I give this consideration no weight.

The extension would provide an open plan games room and sunroom. I recognise that these domestic uses and activities would add to the appellant’s enjoyment and occupation of [address]. However, these would be private, not public, benefits so have little weight in support of the proposal.

A wall opposite part of the site along the north side of Village Road encloses some of the grounds of [address] and is a [name] listed building (the LB). Its significance includes that it dates from the 18th century with distinctive red bricks, vertically laid coping bricks raked to a point and is about 3m high and 450m long. The proposed extension would have no visual or spatial relationship to the wall and, as such, a neutral effect on the setting of the LB. This would therefore preserve the setting of the LB.

The boundary of the Denham Conservation Area (the CA) runs along the south side of this same part of Village Road, adjacent to the site (which is not in the CA). The significance of the CA includes the historic plan form of buildings, plots and roads in the core of Denham village, architectural variety in date, style and building materials and landscaped spaces in the grounds of [address]. Although in the setting of the CA the extension would have a satisfactory design, including materials, integrate well with the existing dwelling and form no part of the Village Road streetscene. The site is distant from the village core and separated from the grounds of [address] by the tall boundary wall. The proposal would therefore have a neutral effect on the CA and thus preserve its character and appearance.

The proposed extension is inappropriate development, which is by definition harmful to the Green Belt. The limited harm to the openness of the Green Belt in this case is nonetheless at odds with local and national policy to protect the Green Belt. Any harm to the Green Belt is a matter that carries substantial weight. There is no other harm in this case.

The other considerations outlined above are therefore individually and cumulatively of insufficient weight to clearly outweigh the harm to the Green Belt. Consequently, very special circumstances to justify the development do not exist. As such, it conflicts with Framework paragraph 148.

The proposal does not accord with the development plan taken as a whole and it conflicts with the Framework. There are no additional considerations which outweigh these findings.

Consequently, for the reasons given above the proposal is unacceptable and the appeal does not succeed.