Enlargement of dwellinghouse by construction of an additional storey

Appeal Decision Site visit made on 26 May 2026 by S Jamieson BA (Hons) MPlan MRTPI Decision by M Russell BA (Hons) DipTP MRTPI an Inspector appointed by the Secretary of State Decision date: 14 July 2026 Appeal Ref: 6005025 44 Shepperton Road, Petts Wood, Orpington, Bromley BR5 1DN • The appeal is made under section 78 of the Town and Country Planning Act 1990 (as amended) against a refusal to grant approval required under Article 3(1) and Schedule 2, Part 1, Class AA of the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended). • The appeal is made by Mr O'Sullivan of Alpha Estates (Petts Wood) Ltd against the decision of the Council of the London Borough of Bromley. • The application Ref is 25/05679/NOT. • The development proposed is enlargement of dwellinghouse by construction of an additional storey. Decision 1. The appeal is dismissed. Appeal Procedure 2. The site visit was undertaken by a representative of the Inspector whose recommendation is set out below and to which the Inspector has had regard before deciding the appeal. Preliminary Matters and Main Issues 3. The description of development is taken from the planning application form. However, I have removed the words ‘See Construction Management Report’ as these do not constitute a description of development. 4. The Town and Country Planning (General Permitted Development) (England) Order 2015 (the GPDO) was amended on 31 August 2020 to introduce Class AA to Part 1 of Schedule 2, setting out permitted development rights for development consisting of the construction of one additional storey on an existing single storey dwellinghouse, together with any reasonably necessary engineering operations. 5. Development is permitted under Class AA subject to various limitations and conditions. Paragraph AA.1 (a) to (k) sets out a number of limitations with which a proposal must comply to fall within the scope of the development permitted by the Class. There is no dispute that the proposal would comply with these limitations. 6. In addition to those limitations, paragraph AA.2 details a number of conditions that must be met. All development is subject to a requirement that details are submitted for prior approval in relation to the matters set out in paragraph AA.2 (3)(a)(i) to (iv). The Council considers that the proposal would not comply with condition (3)(a)(ii) citing harm in relation to the external appearance of the dwellinghouse. Secondly, it considers the proposal would result in an unacceptable impact on living conditions Appeal Decision 6005025 2 of neighbouring occupiers, with specific regard to outlook, such that it would fail to comply with condition (3)(a)(i). 7. The Council have cited a number of development plan policies. As the principle of development has been established through the grant of permission by the GPDO, prior approval appeals are not determined on the basis of s38(6) of the Planning and Compulsory Purchase Act 2004. However, I have taken the development plan policies into account insofar as they are relevant to the prior approval matters under consideration. 8. In view of the above, the main issues are whether prior approval should be granted having regard to the effect of the proposal on: • the external appearance of the dwellinghouse; and • the amenity of adjoining premises, with particular regard to outlook. Reasons for the Recommendation External appearance of the dwellinghouse 9. The appeal relates to a detached bungalow which fronts Shepperton Road, with the side boundaries of its plot adjoining the rear gardens of dwellings on Crescent Drive and Transmere Road. The surrounding area predominately comprises two-storey, semi-detached houses and maisonettes as well as bungalows. Whilst there is architectural variety in the area, there is much commonality in the appearance of dwellings particularly in terms of the traditionality of their simple form, mix of brick and rendered facades and mainly plain hipped roofs. Roof level accommodation is not a common feature of the local street scene. Consequently, whilst the appeal dwelling is single storey, its shared characteristics including its simple form and plain roof positively contribute to the order and cohesiveness of the area. 10. I accept that the upward extension would result in a dwelling of comparable height to others in the area and would incorporate a hipped roof and matching materials. Even so, the intersection of the dormer features with the eaves would appear at odds with the positioning of first-floor windows and the simple, uninterrupted roof slopes that are characteristic of surrounding dwellings. Moreover, on the front elevation, the varying proportions of the dormers, together with the close proximity of the outermost dormers to the main roof hip, would appear poorly resolved and visually discordant. Consequently, whilst dormer style windows might be a common domestic feature in general terms, the particular design and arrangement of window fenestration proposed would not complement the appearance of the host dwelling or the prevailing character and appearance of its immediate surroundings. 11. I accept that the dormers have been incorporated to minimise the height of the upward extension, while ensuring sufficient internal floor to ceiling heights. However, even if the existing bungalow is of limited architectural interest, the discordant design of the upward extension would be highly visible from outside the appeal site, including on approach to the site from Crescent Drive and from nearby gardens and windows. While the proposed landscaping would serve to soften the front of the site, this would be insufficient to effectively screen the discordant appearance of the upward extension. Appeal Decision 6005025 3 12. For these reasons, the proposal would have a harmful effect on the external appearance of the dwellinghouse and so would fail to comply with the condition at AA.2(3)(a)(ii) of Class AA of Part 1 of Schedule 2 of the GPDO. 13. Whilst not determinative, the proposal would also conflict with Policies 6 and 37 of the London Borough of Bromley Local Plan (January 2019) (LP) and Policy D4 of the London Plan (March 2021) insofar as they require developments to deliver good design, positively contribute to the existing street scene and that dormer windows are of a size and design appropriate to the roofscape. Amenity of adjoining premises 14. The rear gardens serving 3 and 3a Transmere Road (Nos 3 and 3a) are narrow. Outlook is channelled towards the appeal site boundary where the existing side elevation of the appeal dwelling currently presents as a substantial wall sitting just beyond, but spanning the width of, the rear boundaries of these neighbouring properties. Despite the hipped roof form and the slight set back from these shared boundaries, the expanse and increased height of the side elevation wall resulting from the upward extension would be an overbearing and visually intrusive feature, unacceptably reducing the quality of outlook from both windows and garden areas to the rear of these adjoining properties. This is regardless of whether the building-to-building separation distances are above the general ‘rule-of-thumb’ distances suggested by the appellant. 15. Due to the relative position of, and angle between, the upward extension and other neighbouring dwellings, a suitably open aspect would be retained both internally and externally from those properties. Even so, that does not overcome the identified harm to outlook for occupiers of Nos 3 and 3a. 16. For these reasons, the proposal would fail to comply with the condition at paragraph AA.2(3)(a)(i) of Class AA of Part 1 of Schedule 2 of the GPDO as it would have a harmful effect on the amenity of adjoining premises. 17. Whilst not determinative, the proposal would also conflict with Policy 37 of the LP which requires that development proposals respect the amenity of occupiers of neighbouring buildings. Other Matters 18. The Council Officer’s report did not identify harm in terms of sunlight / daylight, privacy or highways. There is also nothing to suggest that the site is subject to heritage, ecology, flooding, archaeology or contamination constraints. However, the absence of harm in those particular respects is of neutral consequence. 19. I am not aware of the detailed planning history relating to the examples of side extensions and dormers referred to by the appellant. However, the dormers cited at 37 Chesham Avenue relate to a dormer bungalow, with the dormers of balanced proportions, and this is located some distance from the appeal site. Therefore, it is not similar to the appeal proposal or its more immediate surrounds. The rear gardens of the dwellings that back on to 1 and 12 Addison Close are wider than the gardens at 3 Transmere Road and the relationship between neighbouring side extensions in those particular instances is also therefore not directly comparable to the site-specific harm identified. Appeal Decision 6005025 4 20. The appellant’s personal desire to extend the appeal property to provide modern, functional family-sized accommodation does not justify a proposal which would be harmful. I also acknowledge that this appeal proposal represents a fourth iteration of the prior approval scheme. Nevertheless, an altered proposal does not necessarily equate to one that is acceptable in planning terms, and I have considered the appeal proposal on its own planning merits. 21. Whether or not the forthcoming National Planning Policy Framework update includes specific support for upward extensions, this does not overcome the site-specific concerns identified under the main issues. Conclusion and Recommendation 22. Given the harmful effects identified in respect of the external appearance of the dwellinghouse and the amenity of adjoining premises, the proposal is not permitted under the terms of Schedule 2, Part 1, Class AA of the GPDO. Consequently, and having had regard to all other matters raised, I recommend that the appeal is dismissed. S Jamieson APPEAL PLANNING OFFICER Inspector’s Decision 23. I have considered all the submitted evidence and my representative’s report and, on that basis, prior approval is not given and the appeal is dismissed. M Russell INSPECTOR