Erection of a single storey rear extension

Appeal Decision Site visit made on 7 July 2026 by D Ellis MPlan MRTPI an Inspector appointed by the Secretary of State Decision date: 25 September 2026 Appeal Ref: 6006716 Little Orchard, London Road, Spellbrook, Hertfordshire CM23 4BA • 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 Mr Ergin Altun against the decision of East Hertfordshire District Council. • The application Ref is 3/25/1798/HH. • The development proposed is the erection of a single storey rear extension. Decision 1. The appeal is dismissed. Preliminary Matters 2. A new National Planning Policy Framework (the Framework) was issued on 17 August 2026, which replaces the previous Framework published in December 2024. This latest version of the Framework has introduced plan-making and national decision-making policies and is effect from the day of publication. The appellant and the Council have had the opportunity to comment on the new Framework. Main Issues 3. The main issues are: • whether or not the proposed development would be inappropriate development in the Green Belt; • the effect of the proposal on the openness of the Green Belt; • whether the appeal site would be a suitable location for the proposed development having regard to the risk of flooding; and • if the scheme would be inappropriate development, whether or not 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 necessary to justify it. Reasons Inappropriate development 4. Policy GBR1 of the East Herts District Plan October 2018 (EHDP) states that planning applications within the Green Belt will be considered in line with the provisions of the Framework. Appeal Decision 6006716 2 5. Policy GB6 of the Framework establishes that development in the Green Belt are inappropriate except in certain circumstances as listed in Policy GB7. Paragraph 1.b. of Policy GB7 allows for the extension or alteration of an existing dwelling where the extension or alteration will not result in a disproportionate increase in size compared to the original building. Neither EHDP Policy GBR1 nor the Framework define ‘disproportionate’. 6. The appeal property is a two-storey detached dwelling which has been previously extended. When taken together, the Council states that the previous and proposed extensions would increase the floorspace of the original property by 87.6% and the volume by 89.9%. This would represent a very sizeable cumulative uplift. 7. I agree with the approach taken by Inspectors in the appeals referred to me in that size can be more than a function of floorspace and volume. In this case, the scale, bulk and mass of the building has already been considerably increased through the previous additions. The appeal scheme would increase the massing and scale of the dwelling by a further not insignificant amount. 8. I have been referred to previous appeals to demonstrate that extensions may be acceptable where they remain visually subordinate and contained. However, the appeal references given, APP/X5210/D/17/3181403, APP/A0665/D/19/3225479 and APP/K0425/D/20/3251484 seem to be incorrect. The seven-digit reference numbers relate to appeals APP/B0230/W/17/3181403, which was for an attached dwelling in Luton; APP/G5180/D/19/3225479 which was for a rear extension in Bromley; and APP/T6905/A/20/3251484 which was for a new site access and realigned access road to a caravan park in Conwy. None of these appeal decisions refer to the Green Belt. Notwithstanding this, given the significant extent of the existing and proposed extensions, I am not persuaded that the increase in size would be subordinate and contained. 9. Consequently, and taking all of the above into account, the combination of the previous and proposed extensions would amount to disproportionate additions over and above the size of the original building. The proposal would therefore be inappropriate development which is, by definition, harmful to the Green Belt. This would result in conflict with both the Framework and, by association, EHDP Policy GBR1, the aims of which I have set out above. Openness 10. Openness is an essential characteristic of the Green Belt. Planning Practice Guidance explains that openness can have spatial and visual aspects1. 11. I have been referred to a previous appeal where a rear extension was found not to harm openness due to its limited scale and containment within the curtilage. However, the appeal reference given, APP/W0340/D/18/3209384, also appears to be incorrect. The seven-digit reference number relates to appeal APP/G5180/D/18/3209384 which was for a loft conversion in Orpington, and again the appeal decision does not refer to the Green Belt. 12. Although the proposed extension would have limited visibility from public viewpoints, the land take and mass of the proposed extension, despite its contextually modest size, would take up otherwise undeveloped space in the 1 Planning Practice Guidance paragraph: 013 Reference ID: 64-013-20250225 Appeal Decision 6006716 3 Green Belt. As such, there would be an unavoidable reducing effect on the spatial aspect of its openness. There would be a more limited effect on the visual aspect given the built-up nature of the immediate area. 13. Overall, and taking into account one of the fundamental aims of Green Belt policy being to keep land permanently open, the appeal scheme would reduce the openness of the Green Belt. This harm would be in addition to that caused by the proposed development’s inappropriateness. Flood risk 14. Some of the appeal site lies within Flood Zones 2 and 3, with part of the existing dwelling and proposed extension falling within Flood Zone 2. A Flood Risk Assessment (FRA) was submitted with the application. However, the FRA states that the proposal involves the erection of a two-storey side extension and single storey rear extension and that there will be no alteration to the existing footprint of the property, which is inconsistent with the proposed drawings and application form. The appellant suggests that this inconsistency is a typographical error. 15. Notwithstanding this, I have no reason to believe that the proposed mitigation measures set out in the FRA would be insufficient or that alternative measures would be required should the description of development in the FRA be changed. I therefore have no evidence before me to demonstrate that flood risk would be unacceptably increased by the proposed extension. 16. The proposal would therefore accord with EHDP Policy WAT1, insofar as it requires development proposals to neither increase the likelihood or intensity of any form of flooding. The proposal would also accord with Policy F7 of the Framework, insofar as it requires development proposal to not present a risk from flooding to potential occupiers, users, or visitors, and should not increase flood risk elsewhere. Other Considerations 17. I understand the appellant’s desire to provide additional living space and I afford this moderate weight. 18. There is no evidence before me to suggest that a replacement dwelling would be applied for in the event that this appeal is dismissed. No drawings or details of such a replacement dwelling have been provided. I therefore afford limited weight to the sustainability benefits of an extension instead of a replacement dwelling. 19. The appellant states that a smaller extension could be constructed under permitted development rights. No drawings or substantive details of such an extension, nor an associated Certificate of Lawful Development, have been provided. Nevertheless, a smaller extension would have less of an impact on the Green Belt and its openness and therefore would not justify a larger, more harmful extension. 20. I note the lack of objection from statutory consultees and that the Council has not objected on the grounds of highways, environmental considerations, living conditions of neighbouring residents and the character and appearance of the area. However, these represent a lack of harm which are neutral matters in the planning balance. Appeal Decision 6006716 4 Other Matters 21. The Old Cottage is a grade II listed building to the north of the appeal site. The cottage was built in C17 and the roof raised in C18. Insofar as it is relevant to this appeal, the historic nature and architectural details contribute strongly to the significance of the listed building. Given the modest, in context, scale of the proposed extension, the separation between the appeal building and the Old Cottage, and the existing boundary landscaping, the proposal would not affect the setting of the listed building. Conclusion 22. Policy S3 of the Framework sets out that decisions on development proposals should apply a presumption in favour of sustainable development. For development within settlements, such as the appeal proposal, Policy S4 of the Framework states that development proposals should be approved unless the benefits of doing so would be substantially outweighed by any adverse effects, when assessed against the national decision-making policies in the Framework. 23. The proposed extensions would cause harm to the Green Belt by way of inappropriateness and through reducing openness, to which substantial weight should be afforded. Development should not be approved unless the harm to the Green Belt, and any other harm, is clearly outweighed by other considerations. Those I have identified would not attract sufficient weight to clearly outweigh the totality of the harm and subsequent development plan conflict. The proposal would also fail to accord with Policies GB6 and GB7 of the Framework. Consequently, the very special circumstances necessary to justify the proposed development do not exist. I am therefore satisfied when having regard to paragraph 2.c. of Policy S4 of the Framework that the benefits of the scheme would be substantially outweighed by the adverse effects. 24. I therefore conclude that the proposal conflicts with the development plan and that material considerations do not indicate that the appeal should be decided other than in accordance with it. The appeal should therefore be dismissed. D Ellis INSPECTOR