Appeal 3356121

The appeal is dismissed.

A revised National Planning Policy Framework (the Framework) was issued in December 2024. This includes changes to the national Green Belt policy; however, there are no direct alterations to the pertinent section regarding extensions to buildings in the Green Belt. I am therefore satisfied that there is no prejudice by the change to the national planning context. For clarity, any references in my decision to the Framework and its paragraph numbers are to the latest 2024 version.

The main issues are: • whether the proposal would be inappropriate development in the Green Belt having regard to the Framework and any relevant development plan policies; • the effect on the openness of the Green Belt; • the effect of the proposal on the character and appearance of the area; and • on the basis that the proposal would be inappropriate development in the Green Belt, whether any harm by reason of inappropriateness, and any other harm, would be clearly outweighed by other considerations so as to amount to very special circumstances required to justify the development.

The Framework establishes that development within the Green Belt should be regarded as inappropriate unless one of the specified exceptions applies. Exception (c), as set out in paragraph 154 of the Framework, allows for the extension and alteration of a building, provided that it does not result in disproportionate additions over and above the size of the original building.

Policies DP10 and DP13 of the Tandridge Local Plan Part 2: [name] 2014 – 2029 (July 2014) (Local Plan) generally reflect the approach in the Framework, although policy DP13 uses a date of 31 December 1968, rather than 1 July 1948 as set out in the Framework, for the original building. The property has existing alterations, but as these were post-1968, the difference in the assessment dates is not consequential in relation to the appeal scheme.

Both parties agree on the figures set out in the Council’s officer report in relation to the volume of the original dwellinghouse and the increase, which indicates that the proposed extension is 177m3 and equates to an increase of 43.8%.

The Council indicate that volumetric uplifts of around 40% are typically allowed, although this is not defined in the policy, and the supporting text to policy DP13 indicates that a pragmatic approach will be taken and notes the Framework does not define “disproportionate additions”. It is, therefore, a matter of judgment. The supporting text does, however, advise that as a general rule, the Council will use the external volume for the assessment and that any detached structures within the curtilage will be excluded from the calculation.

The appeal property is a relatively narrow, semi-detached house. The proposal would substantially increase the width of its frontage, and whilst single storey, it would be an elongated form which would extend more or less the full width of the plot and would be disproportionately wide compared to the original house.

To facilitate the proposed development, an existing side extension and a detached outbuilding would be removed. However, the scale of the outbuilding, the size of the plot, and the presence of similar structures to other properties nearby are not factors which directly affect the assessment for exception (c), which is a comparison of the size of the extension(s) to the original building.

Consequently, I find that the extension would be a disproportionate addition. Even if, as suggested by the appellant, the semi-detached building is taken together as a whole, the extensive horizontal form would still be disproportionate, and there are no details before me to consider the cumulative effect of all additions.

I therefore conclude that the proposal would be inappropriate development in the Green Belt, having regard to the Framework and Policies DP10 and DP13 of the Local Plan.

The Framework states that the fundamental aim of Green Belt policy is to prevent urban sprawl by keeping land permanently open. Openness in terms of the Green Belt has a spatial aspect as well as a visual aspect.

Together with the existing outbuilding and boundary fencing, there are structures across the width of the plot. There is nonetheless a visual gap and distinction between the house and the outbuilding, which has the general appearance from the street of a garage-type structure. The mono pitched roof form of the extension would have a lower height than the outbuilding and would be set back behind a fence with a further row of hedging closer to the road.

The spatial increase in built form would be limited, effectively infilling between the outbuilding and the house, and in the context of the setting as part of a residential street, the impact on the wider appearance of the Green Belt would be negligible. Nonetheless, there would be some localised harm to openness. Accordingly, it adds to the harm to the Green Belt.

The semi-detached property is located at the end of Park Road, with open fields to the other side of [address]. The properties along Park Road are a mixture of houses and bungalows. Many, especially the bungalows, have garages/single-storey elements to the side forming wide frontages and have a horizontal emphasis.

In contrast, the Victorian semi-detached properties have a vertical form. The appellant advises that the design and materials of the extension are a deliberate choice to distinguish it from the original building. I accept that contemporary elements can sit alongside traditional ones, and the single-storey nature of the proposal would not lead to a terracing effect. However, in this instance, the extension with a width of approximately 10m would appear incongruous and would fail to assimilate with the appearance of the host property. A large proportion of the extension would be screened but planting is not permanent, and the lack of prominence does not alter the form and design of the extension being out of keeping with the prevailing character and appearance of the area.

The development would therefore conflict with the requirements of Tandridge District Core Strategy ([name]) policy CSP 18 and policy DP7 of the Local Plan which promote a high standard of design, to respect the character, setting and features which contribute to local distinctiveness, for built form to reflect the local building types and materials, and not result in unacceptable overdevelopment by reason of scale, form, spacing and design.

The appellant explains that the proposal is to incorporate an accessible entry hall and a ground-floor bedroom with bathroom facilities suitable for people with reduced mobility. [name] sympathise with the appellant’s circumstances and concerns regarding the lack of availability of such accommodation, there is nothing before me which indicates that accessibility provisions could not be achieved through a different design, form or size of extension.

It is also suggested that permitted development rights could be utilised for an outbuilding in a similar position. I have no specific details of such a scheme but given that the proposal is seeking to integrate alterations to make the existing property usable by some with mobility issues, a detached building would not achieve the same objective. As such, I do not find that this represents a genuine fallback. I nonetheless acknowledge that the property has a large plot, and an additional outbuilding could be added.

Reference is made to a number of other appeal decisions where extensions of a similar or larger percentage increase have been allowed. The full details of these other cases are not before me, nevertheless, these additions were not assessed on a mathematical volume calculation alone, and as set above, it is the width of the extension in this case which contributes to the disproportionality.

Very special circumstances can only exist if the harm I have identified is clearly outweighed by other considerations. I have found harm to the Green Belt by way of inappropriateness and openness, and other harm in terms of the impact on the host property and the character of the area. As set out in paragraph 153 of the Framework, substantial weight is given to harm to the Green Belt. Despite having regard to all the other considerations put before me in favour of the scheme by the appellant, I conclude that these other considerations taken together, do not clearly outweigh the harm that I have identified to the Green Belt.

The development would conflict with policies DP10 and DP13 of the Local Plan, both of which relate to development in the Green Belt, and [name] policy CP18 and Local Plan policy DP7 in relation to design. Accordingly, the very special circumstances necessary to justify the proposal do not exist, and the proposal does not represent sustainable development.

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