Appeal 3320027

The appeal is dismissed.

The appeal site is within the Green Belt and so the main issues are: • Whether or not the proposed development would be inappropriate development in the Green Belt having regard to the National Planning Policy Framework (2023) (the Framework) and any relevant development plan policies; • The effect of the proposed development on the openness of the Green Belt; and • If the proposed development is inappropriate development, whether the harm by reason of inappropriateness, and any other harm, is clearly outweighed by other considerations so as to amount to the very special circumstances required to justify the proposed development.

The appeal property is a detached bungalow. It is located on a section of [address] where there are residential properties of various sizes and designs on both sides of the street. The property is set slightly back from the road and is set in spacious grounds. The property has a low pitched roof and has been extended to the front, rear and sides.

The proposed development would involve the construction of a new roof over the main body of the dwelling and the garage to the side to provide new roof level accommodation. This would include the addition of dormer windows. The proposed development also includes the provision of a new roof to the existing single storey side and rear extensions.

The National Planning Policy Framework (2023) (the Framework) identifies that the fundamental aim of Green Belt policy is to prevent urban sprawl by keeping land permanently open. The Framework outlines that the construction of new buildings should be regarded as inappropriate in the Green Belt subject to a number of exceptions as set out in paragraph 149. One of the exceptions cited is 149 c) 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 49 of the Bromley Local Plan (2019) is consistent with the Green Belt aims of the Framework and includes the same exception from the Framework as set out above.

The ‘original building’ is defined as the building as it existed on 1 July 1948 or if constructed after this date, as it was originally built. The Framework does not define what constitutes a ‘disproportionate’ addition. Policy 51 of the Bromley Local Plan sets out, amongst other things, that extensions or alterations to dwellinghouses in the Green Belt will only be permitted if the net increase in the floor area over that of the original dwellinghouse is no more than 10%, as ascertained by external measurement.

The appeal property has been notably extended from its original form. This is set out in the Council’s evidence and from my own observations on my site visit.

The development would significantly increase the habitable floorspace at the property. It would, however, use some of the existing roof-space volume and would be confined to the existing footprint of the property.

Having regard to Policy 51 of the local plan, the Council outline that the existing extensions have resulted in a net increase above the 10% threshold as outlined in the Policy. From the evidence before me and my own observations, I have no reason to form a different view. The Council set out that the proposed development would provide an additional 94.6sqm, an increase of 38% from the existing floor area of 246.5sqm.

Notwithstanding the additional habitable floorspace that would be created, which the appellant suggests is not ‘new’ floor area, it is without doubt that the development adds a significant volume to the property. Even though the Council’s policy relates to floor area, I am firmly of the view that volume is a pertinent factor when considering whether or not an extension or alteration of a building would result in disproportionate additions over and above the size of the ‘original building’. Not least in consideration of the proposed development against the relevant sections of the Framework.

The appellant suggests that the Council’s threshold of 10% may restrict extensions that might otherwise be regarded as proportionate. I agree that there may be occasions where an extension representing an increase greater than 10% of the original dwelling may still be deemed proportionate, in the context of the language in the Framework. However, in this case, when considered against the original dwelling, the proposed development, when combined with the existing extensions, would significantly exceed the size of the original building and would be disproportionate.

Therefore, due to its overall size, scale and volume, the proposed development when taken with other previous extensions to the property, would result in disproportionate additions over and above the size of the original building in the terms of paragraph 149 of the Framework and Policies 49 and 51 of the local plan. For these reasons, the proposal would be inappropriate development in the Green Belt and would be contrary to Policies 49 and 51 of the local plan. This is a matter to which I afford substantial weight in the planning balance.

The Framework outlines that one of the essential characteristics of Green Belts is their openness. Openness has a spatial aspect as well as a visual aspect.

The proposed development would not increase the overall footprint of the property. It would, however, result in a significant increase in the overall scale, mass and volume of the existing property. It therefore would have a greater impact on the openness of the Green Belt in spatial terms. I find that in light of the overall size and scale of the development, the harm to the openness of the Green Belt from a spatial aspect would be relatively moderate.

The dwelling is set slightly back from the roadside and there is a notable amount of landscaping surrounding the site. The extension would be sensitively designed and be confined to the footprint of the existing dwelling. Nevertheless, the roof alteration would significantly increase the visual prominence of the dwelling in the Green Belt. As a domestic extension to an existing dwelling, I find that there would be moderate harm to the openness of the Green Belt from a visual point of view.

Therefore, overall, I consider that the effect on the openness of the Green Belt would be moderate, and I give this harm moderate weight in the appeal.

Paragraph 147 of the Framework states that inappropriate development is, by definition, harmful to the Green Belt and should not be approved except in very special circumstances. Paragraph 148 continues by stating that very special circumstances will not exist unless the harm to the Green Belt by way of inappropriateness, and any other harm, is clearly outweighed by other considerations.

The development in this case amounts to inappropriate development in the Green Belt and the Framework requires that substantial weight is attached to the harm in that regard. It would also cause moderate harm to the openness of the Green Belt.

The appellant outlines how the proposed development would not cause harm to the character and appearance of the area, a matter to which the Council also concurred. In terms of its design, and notwithstanding my consideration in relation to the Green Belt, I am also of the view that the design of the development would not cause harm in itself. The absence of harm, however, is a neutral factor in the balance. The same applies in relation to the fact that no harm would be caused to living conditions.

[name] accept that the design of the development does not cause harm, and is reasonably well designed, I do not consider it to be of such high quality in design terms that would allow me to afford this matter significant weight in favour of the appeal. In this regard, whilst I find its design does not harm the street-scene, I do not consider that it enhances the street-scene as suggested.

The fact that there is chalet style, two storey properties, and properties with roof-space accommodation nearby does not alter my view on the main issues in terms of the Green Belt. I therefore give this limited weight in the appeal.

The proposal would constitute inappropriate development in the Green Belt. When considered as a whole, moderate harm would be caused to the openness of the Green Belt. The substantial weight to be given to Green Belt harm arising from the proposal would not be clearly outweighed by the other considerations as outlined above. Consequently, the very special circumstances necessary to justify the development do not exist. Therefore, the proposed development would not accord with the Green Belt aims of the Framework and the Bromley Local Plan.

For the reasons given above, and having had regard to all other matters raised, I therefore conclude that the appeal should be dismissed.