Single storey rear extension, additional stepped access to rear, conversion of existing garage and addition of bay window to match existing to front elevation

Appeal Decision Site visit made on 13 August 2026 by K E Down MA(Oxon) MSc MRTPI an Inspector appointed by the Secretary of State Decision date: 24 August 2026 Appeal Ref: 6009956 36 Amersham Hill Drive, High Wycombe, Bucks, HP13 6QY • 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 & Mrs Swatton against the decision of Buckinghamshire Council. • The application Ref is PL/25/5116/FA. • The development proposed is a single storey rear extension, additional stepped access to rear, conversion of existing garage and addition of bay window to match existing to front elevation . Decision 1. The appeal is allowed and planning permission is granted for a single storey rear extension, additional stepped access to rear, conversion of existing garage and addition of bay window to match existing front elevation at 36 Amersham Hill Drive, High Wycombe, Bucks, HP13 6QY in accordance with the terms of the application, Ref PL/25/5116/FA, subject to the following conditions: 1) The development hereby permitted shall begin not later than 3 years from the date of this decision. 2) The development hereby permitted shall be carried out in accordance with the following approved plans: SWA 1.00, SWA 1.08. 3) The materials to be used in the construction of the external surfaces of the development hereby permitted shall match those used in the existing building. 4) The rear extension hereby permitted shall not be occupied until the long windows in the side elevations have been fitted with obscure glazing, and no part of those windows that is less than 1.7m above the floor of the room in which they are installed shall be capable of being opened. Once installed the obscured glazing and limited opening shall be retained thereafter. 5) The extensions hereby permitted shall not be brought into use unless one ecological feature comprising either a bird box, bat box or bug hotel has been installed within the curtilage of the site, in a position suitable for its intended use. It shall thereafter be retained. Main Issue 2. There is one main issue which is the effect of the proposed rear extension on the living conditions of occupiers of 34 Amersham Hill Drive with respect to light, outlook, enclosure and privacy. Appeal Decision Ref: 6009956 2 Reasons 3. The appeal dwelling is a large, detached house in a street of other large detached dwellings. It and its neighbours sit on land below street level with gardens that fall away to the rear. Those on the opposite side of the street are at a higher level than the highway. 4. The Council raises no objection to the proposed garage conversion or the addition of a bay window to match the existing in the front elevation, and I agree this would be acceptable. 5. Although one neighbour objects to the proposed rear extension on grounds of its character and appearance, I agree with the Council that it would be acceptable in terms of scale and design and in the context of the host dwelling. In consequence, I do not consider it would be likely to diminish property values in the area, but in any case, this is not a material planning consideration. I shall therefore restrict my further consideration to the effect of the proposed rear extension on the living conditions of occupiers of 34 Amersham Hill Drive. 6. No 34 sits forward of the appeal dwelling and so its main rear elevation is set back from that at the appeal dwelling. However, a single storey side element on the shared boundary, which appears to be a former garage now converted to habitable space, projects behind the main façade at No 34 to within a short distance of the rear elevation at No 36. It has a rear facing window and is also illuminated by a rooflight. Beyond this and close to the shared boundary, there is a seating area with a solid pyramid roof. The house has a large patio to the rear, similar to the one at the appeal dwelling but set down from its host dwelling, with steps down to the garden beyond. 7. The appeal dwelling has an existing, modest single storey rear projection. The proposed single storey rear extension would replace and extend beyond this. It would project some 5m beyond the line of the existing rear projection and would extend from the existing side wall, which lies about 1.5m from the shared boundary. The final section of the extension would be stepped in by about a further 1.9m to ensure compliance with the Council’s 60° rule, set out in its Householder Planning and Design Guidance Supplementary Planning Document (SPD), adopted 2020. 8. There is a level difference between ground levels at the rear of the appeal dwelling and No 34, particularly further from the rear façade where the patio at the appeal site sits noticeably higher than that at No 34. Nevertheless, owing to the distance between the proposed extension and the shared boundary, the more limited level difference close to the rear of the dwellings, the limited height of the proposed extension and the position of No 34, to the south-west of the appeal site, I am satisfied that no material loss of sunlight or daylight or any noticeable overshadowing would arise to either the dwelling or the rear patio at No 34. In particular, the closest room, served by a window and rooflight, would continue to receive adequate illumination. 9. In terms of outlook, owing to the existing high boundary fence and vegetation on both sides of the shared boundary, together with the separation distance between the boundary and the proposed extension, I am satisfied that it would not appear overbearing when seen from No 34, notwithstanding the difference in levels, and neither would it result in a material increase in the sense of enclosure, given the Appeal Decision Ref: 6009956 3 wide, sunny outlook to the rear of No 34 over its own large garden. Moreover, a large, dense, holly tree in the garden of the appeal site and close to the shared boundary which currently screens outlook to the north-east would be removed as part of the proposed development. 10. The proposed rear extension would have long side windows at its furthest extent facing both neighbouring dwellings. Owing to their elevated position compared with the lower sections of the neighbouring gardens there would be a risk of material overlooking above the boundary fences and consequent loss of privacy. I therefore agree with the Council that these windows should be obscure glazed and non- opening below 1.7m above the floor level of the room they serve. I will impose a suitable condition. Similar provisions would not be necessary in respect of the other side window in the elevation facing No 38 since this would face towards the existing high boundary fence, ensuring no material overlooking of the neighbouring property. 11. It is concluded on the main issue that the proposed extension would have no material effect on the living conditions of neighbours at 34 Amersham Hill Drive with respect to light, outlook, enclosure or privacy. In consequence, there would be no conflict with Policies DM35 and DM36 of the Wycombe District Local Plan (LP), adopted 2019, or the Council’s SPD. Taken together and amongst other things these expect new development to improve the character of the area and the way it functions, be of a high quality of detail and design and, in particular, preserve the amenities of neighbouring properties, including outlook and light. 12. In addition to the statutory commencement condition, I agree with the Council that the development should be carried out in materials that match those used in the existing building. It should also be carried out in accordance with the approved plans. Both these conditions are necessary to preserve the character and appearance of the host dwelling and the surrounding area. As set out above, in order to preserve the privacy of neighbouring occupiers, I will also impose a condition regarding obscure glazing and limited opening in the proposed long, side facing windows. 13. Finally, although the loss of garden, other than the hard surfaced patio, would be limited, a large holly tree would be removed, and some other vegetation would be lost. Policy DM34 of the LP expects such loss to be compensated for. This is necessary to maintain biodiversity in the area. I agree with the Council that this could be achieved through the provision of either a bird box, bat box or bug hotel and that this would be a proportionate and hence reasonable level of mitigation. I will therefore impose a suitable condition to secure this. 14. For the reasons set out above and having regard to all other matters raised, I conclude that the appeal should be allowed. K E Down INSPECTOR