Single storey rear extension, first floor extension over existing side extension. Double garage

Appeal Decision Site visit made on 2 December 2025 by Stewart Glassar BSc (Hons) MRTPI an Inspector appointed by the Secretary of State Decision date: 16th December 2025 Appeal Ref: 6000944 The Beams, Puddledock Lane, Hextable, Kent DA2 7QE • The appeal is made under section 78 of the Town and Country Planning Act 1990 (as amended) against a refusal to grant planning permission. • The appeal is made by Sibu Thomas against the decision of Sevenoaks District Council. • The application Ref is 25/00942/HOUSE. • The development proposed is described as ‘single storey rear extension, first floor extension over existing side extension. Double garage.’ Decision 1. The appeal is dismissed. Main Issues 2. The main issues are: a) Whether or not the proposed development would be inappropriate development in the Green Belt, having regard to the National Planning Policy Framework and any relevant development plan policies; b) The effect of the proposed development on the openness of the Green Belt; and c) 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. Reasons 3. The National Planning Policy Framework (the Framework) stipulates that development in the Green Belt should be regarded as inappropriate unless it accords with one of the exceptions set out in the Framework. It states that inappropriate development is, by definition, harmful to the Green Belt and that any harm should be given substantial weight. 4. Both main parties have referenced the exception at Paragraph 154 (c) which allows 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’. None of the other exceptions to inappropriate development set out in the Framework were identified by the main parties as being relevant to the extensions. 5. Policy GB1 of the Sevenoaks Allocations and Development Management Plan 2015 (ADMP) is broadly consistent with the Framework insofar as it requires Appeal Decision 6000944 2 extensions to dwellings in the Green Belt to be proportional and subservient to the original dwelling, and to not materially harm Green Belt openness. It also requires that the total floorspace of all existing and proposed extensions do not cumulatively result in an increase of more than 50% above that of the original dwelling. Whilst the Framework does not provide this level of detail, the policy is not inconsistent with the overall aims of the Framework. 6. The Framework does not define ‘disproportionate additions’, and so it is a matter of planning judgement. It does, however, define an original building as being one as it existed on 1 July 1948 or, if constructed after that, as it was built originally. The supporting text to Policy GB1 also states how the word “original” should be interpreted in the context of that policy. This definition does not conflict with the definition of an original building as set out in the Framework. 7. The evidence before me indicates that the dwelling that currently exists at the site is a replacement dwelling. Therefore, for the purposes of this appeal, the original building is the previous dwelling which was demolished. 8. The Officer Report suggests that the original dwelling had a floor area of 246.9 m². The appellant does not dispute this figure. There is a difference of opinion between the main parties as to the current dwelling’s floorspace. However, even taking the appellant’s figure of 322.9m², when considered in tandem with the proposed extensions the resulting building would exceed the permitted 50% increase in floor area over the original dwelling. The appellant points to the removal of the existing conservatories but even taking that into account the resulting uplift in floorspace exceeds 50% of the original building. 9. I am also mindful that Paragraph 154 (c) of the Framework, refers to ‘size’, a term which encompasses more than simply a comparison of floorspace figures. The ‘size’ of a building can reasonably be taken to include such factors as volume, height, external dimensions, visual perception etc. 10. The proposal involves extensions to the front and rear of the building, noticeably increasing its overall depth. The single storey eastern wing would become two storeys and match the height of the existing roof ridge. It would also enable the existing front dormer to become a wider upper gable. 11. Although I have not been provided with any drawings of the original building, when considering the evidence before me, it is my planning judgement that the overall size of the building as now proposed cannot reasonably be considered to result in anything other than disproportionate additions over and above the size of the original building. 12. Thus, I am unable to conclude other than that the proposal would be inappropriate development in the Green Belt. The proposal would therefore conflict with the Framework and Policy GB1 of the ADMP which both seek to protect the Green Belt from inappropriate development. Openness 13. Paragraph 142 of the Framework states: ‘the fundamental aim of Green Belt policy is to prevent urban sprawl by keeping land permanently open; the essential characteristics of Green Belts are their openness and their permanence’. Openness is not defined in the Framework but in determining the nature and Appeal Decision 6000944 3 extent of any impact on Green Belt openness it is necessary to assess both spatial and visual impacts. 14. As noted above, the works would result in the house having an extended footprint, volume and mass. This would find particular visual and spatial expression in its greater depth and in the dwelling extending across two storeys for its full length. 15. The proposal would also entail a new double garage. It would be positioned adjacent to an existing outbuilding which itself is positioned on lower lying ground, forward of the dwelling. The officer report indicates that the garage would extend the footprint of built form by some 53.6m², a figure the appellant does not dispute. 16. Caselaw has established that outbuildings can also be considered as an extension to a building, even when physically detached from the dwelling. In this case the Council has not considered the proposed double garage as an extension to the dwelling under Policy GB1 as it is more than 5m from the dwelling. I see no reason to disagree with this approach. 17. Policy GB3 of the ADMP and the guidance in the Supplementary Planning Document ‘Development in the Green Belt’ seek to restrict outbuildings to 40m² gross external area in order to minimise their effect on the openness of the Green Belt. The garage would result in a sizeable building where none currently exists. 18. The site is in a secluded location and the house itself is set within a large plot, well back from the road and behind vegetated boundaries and a gated entrance. Thus, direct visibility of the appeal buildings from the public realm is highly unlikely. 19. In this context, even if I were to find there would be no harm to the visual dimension of the openness of the Green Belt, there would be the spatial dimension to consider. Whilst the spatial changes would be limited and localised there would nonetheless be a small but noticeable loss of openness as a consequence of the additional built form proposed. 20. This would be contrary to the guidance in the Framework as well as the provisions of Policy GB3 of the ADMP which seek to protect the openness of the Green Belt. As per Paragraph 153 of the Framework, any harm to the Green Belt, including harm to its openness, attracts substantial weight. Other Considerations 21. The works are said to be sympathetic to the existing dwelling, as well as to the neighbouring occupiers. However, these were not contentious issues in this appeal and a lack of harm in these respects should be an expectation of all development. Therefore, they are neutral factors in this appeal. 22. The proposal would improve the building’s sustainability credentials albeit no specific details are provided. Building Regulations will inevitably seek to ensure that insulation and glazing is installed to the current standards, which are likely to be an upgrade on the existing fitments. Thus, there would likely be an inherent improvement in the building’s sustainability and energy efficiency. In the circumstances I give this matter only a small amount of positive weight. 23. It is said that the proposal would improve the quality of the accommodation. I accept that the internal accommodation may benefit from some upgrading and remodelling, but the house is not unusable or uninhabitable. The internal Appeal Decision 6000944 4 improvement to one house would carry only limited weight in the context of this appeal. 24. The proposed changes to the accommodation would also meet the needs of the appellant. However, any permission runs with the land, and the Planning Practice Guidance advises that only in exceptional circumstances will development that would not normally be permitted be justified on planning grounds because of who would benefit from the permission. However, there is no evidence before me to suggest that those exceptional circumstances apply here. 25. I appreciate that some neighbouring properties may have similar or larger sizes or footprints than that proposed in this appeal. However, there is no requirement to ensure that dwellings in the area are of a similar size. 26. I understand from the application form that pre-application advice was received from the Council. I have not been provided with details of the scheme as initially presented nor the extent to which any changes may have been made following the receipt of that advice. However, pre-application advice is not binding and so does not prevent the Council from reaching a different formal decision nor would it be a reason in itself to allow the appeal. 27. I have been referred to other appeals from elsewhere in Sevenoaks. However, I have not been presented with the specific details of those cases and so cannot be sure of the extent to which they are comparable to the current proposal. Furthermore, each case must be considered on its own merits. Green Belt Balance 28. I have concluded that the appeal scheme would be inappropriate development that would, by definition, harm the Green Belt. I have also concluded that the appeal scheme would result in limited harm to the openness of the Green Belt. Paragraph 153 of the Framework requires substantial weight to be given to any harm to the Green Belt. 29. Consequently, such development should not be approved except in very special circumstances. In order to constitute very special circumstances, the circumstances cited in support of a proposal must not just outweigh the harm to the Green Belt but clearly outweigh it. I have considered the matters put before me in favour of the scheme. However, for the reasons given, I conclude that these other considerations as presented and when taken together do not clearly outweigh the substantial weight I have afforded to the Green Belt harm. Consequently, the very special circumstances necessary to justify the development have not been shown to exist in this appeal. Conclusion 30. The development is contrary to the Framework and to the development plan when taken as a whole. I have considered all other matters raised but none outweigh the conclusions I have reached. For the reasons set out above, I dismiss the appeal. Stewart Glassar INSPECTOR