Appeal 3280427

The appeal is dismissed.

The main issues are: • whether the proposal would be inappropriate development in the Green Belt having regard to the National Planning Policy Framework and any relevant development plan policies; • the effect of the proposal on the openness of the Green Belt; • the effect of the proposed development on the character and appearance of the host property and the surrounding area, including the Chilterns Area of Outstanding Natural Beauty (AONB); and • if the proposal is inappropriate, whether the harm by reason of inappropriateness, and any other harm, would be clearly outweighed by other considerations. If so, would this amount to the very special circumstances required to justify the proposal.

The appeal property is a semi-detached dwelling set within a generous plot. It is located on the north-western side of [site address] in a small group of 3 dwellings. These are surrounded by open countryside. The site lies within the [name]. It is also located within the Green Belt.

The construction of new buildings should be regarded as inappropriate in the Green Belt subject to a limited number of exceptions as set out in paragraph 149 of the National Planning Policy Framework (the Framework). One of the exceptions is 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. The Framework does not define ‘disproportionate’.

Policy DM43 of the Wycombe District Local Plan 2019 (the LP) sets out the Council’s approach to residential extensions in the Green Belt. It uses volume to assess whether an extension would be appropriate development. The policy sets out that for dwellings with an original volume of less than 240 cubic metres, the total volume of the resulting building should be no more than 360 cubic metres.

The original dwelling is a modestly-sized two-storey property. The Council has indicated that it was originally 226.7 cubic metres in volume. It has already been significantly extended with a part 2/part single-storey side and rear extension. These have added just over 167 cubic metres, equivalent to a 74% increase in volume. This has already exceeded the threshold set within Policy DM43 as the building has been increased in size to approximately 394 cubic metres.

The proposed extension would be single-storey and largely set within an existing sunken patio area to the side of the property. When considered in isolation, the proposed extension would be modest in size, with a footprint of 13.[address] metres and a volume of just over 39.5 cubic metres. Whilst the extension would amount to a 10% increase above the current building size, the added volume needs to be considered in terms of the original. In combination with the previous extensions, this would result in a building with a volume of a little under 434 cubic metres. When considered cumulatively with those previous extensions, the proposed development would amount to a disproportionate enlargement to the original building which would nearly double the size of the original dwelling.

The siting of the appeal property within a large plot is not a relevant factor in determining whether or not the extension would be a disproportionate addition.

Accordingly, when considered cumulatively with previous extensions to the original dwelling, the extension would be inappropriate development, which is, by definition, harmful to the Green Belt.

Paragraph 137 of the Framework states that the fundamental aim of Green Belt policy is to prevent urban sprawl by keeping land permanently open. It identifies openness as an essential characteristic of the Green Belt. There is no definition of ‘openness’ in the Framework although it is commonly taken to mean the absence of built or otherwise urbanising development. An assessment of openness requires a consideration of the scale of the development, its locational context and both its spatial and visual implications.

The proposed extension would increase the footprint of the building. However, as it would have both a very modest footprint and be largely set within an already excavated / sunken patio area, enclosed by a nearly 2m high retaining wall, its effect in spatial terms would be limited. Only the upper section of the proposed extension would be visible. This would be limited in height and largely screened from any public viewpoints by the orientation of the house to the road and its set back from the public realm. Its visual effect on openness would also be limited

I conclude that the appeal proposal would result in a small loss of openness thereby causing limited harm to the Green Belt. Therefore, it would be contrary to the objectives of the Framework.

The appeal site lies within the open countryside and [name]. The wider area is characterised by large, open and gently sloping fields which surround the appeal site and the 2 adjacent properties with [site address] running to its south-east, at a lower level than the appeal property. The host property is a modestly sized 2-storey cottage. Its traditional character and appearance contributes to the built heritage, character and quality of the rural landscape in which it sits.

The proposed extension would be adjacent to an existing 2-storey extension. It would be set lower than the gardens which surround it and would be largely screened from the surrounding countryside and the highway.

However, the extension would be of a poor design with a ‘false’ pitched roof, comprising a partial pitch and a substantial area of flat roof. This would not be in keeping with the character of the host property which has a more traditional ridged roof. Furthermore, whilst lower in height and therefore subordinate to the host property in that regard, the proposed extension would appear disproportionately wide when viewed from the front. Together the roof design and excessive width of the proposed extension would make it appear as a discordant feature, visible as part of the main front elevation of the building.

Since the extension would be largely located within the existing sunken patio area, it would require limited excavation which would help reduce some of its impact and intrusion into the landscape. Nevertheless, this would not overcome the poor design of the proposal when viewed in the context of the original dwellings.

The poor design of the proposed extension would harm the character of the host property. It would fail to respect the built heritage of the AONB and would therefore detract from its character. In accordance with paragraph 176 of the Framework, I attach great weight to conserving and enhancing the landscape and scenic beauty in the AONB.

The proposed external materials, whilst matching those of the existing property, would not overcome the shortcomings in the design of the proposed extension.

I therefore conclude that the proposed extension would harm the character and appearance of the host property and the surrounding area, including the [name]. It would therefore conflict with Policies CP9, DM30 and DM36 of the LP which together seek a high quality sense of place, through development being a high quality of design, which respects the built heritage of the [name], and respects the character and appearance of the existing property.

The existing cottage is modest in size with limited internal accommodation. The appellant is seeking the enlargement of the dwelling to make it more suitable for modern day living. Whilst this would certainly increase the space within the appellant’s home, I have been provided with no compelling reasons to justify the extension. I therefore attach limited weight to this.

I have concluded that the proposal would be inappropriate development and would therefore, by definition, be harmful to the Green Belt. I have also found that it would cause limited harm to the openness of the Green Belt. These are matters to which I give substantial weight as required by paragraph 148 of the Framework.

In addition, the proposed extension would harm the character and appearance of the host property and the surrounding area, including the AONB.

There are no other considerations in favour of the proposal that clearly outweigh the harm I have identified. Consequently, the very special circumstances necessary to justify the development do not exist.

As such the proposed development would be contrary to the Framework. It would also conflict with Policies CP8 and DM43 of the LP which set out that the Green Belt should be protected against inappropriate development.

For the reasons set out above, I conclude that the appeal should be dismissed.