Follows: “Hip-to-gable roof extensions, rear dormer and alteration of first floor hipped roof to flat roof

Appeal Decision Site visit made on 9 July 2025 by R C Shrimplin MA(Cantab) DipArch RIBA FRTPI FCIArb MCIL an Inspector appointed by the Secretary of State Decision date: 31 July 2025 Appeal Reference: APP/R5510/D/25/3366468 26 Mount Pleasant, Ruislip HA4 9HG • 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 Mrs. L. Dunn against the decision of the Council of the London Borough of Hillingdon. • The application reference is 58370/APP/2025/649. • The development proposed is described in the application form as follows: “Hip-to-gable roof extensions, rear dormer and alteration of first floor hipped roof to flat roof”. Decision 1. The appeal is dismissed. Main issues 2. The first main issue to be determined in this appeal is the effect of the proposed development on the character and appearance of the host building and its surroundings. The second is whether the scheme would provide satisfactory living conditions for occupiers of the proposed new residential accommodation (in terms of outlook). Reasons 3. The appeal site is located within an extensive residential area of Ruislip, in the north-east part of the town. The area is closely built-up, with a variety of house types and deigns, but it is clearly suburban in character. The houses along Mount Pleasant are set back from the highway and, although off-street parking spaces have been created within front gardens, the character of the streetscene is softened by planting in the gardens, as well as by some trees in the highway footpaths. 4. The houses themselves, along Mount Pleasant, are mostly two-storey detached houses, although semi-detached houses and short terraces are to be found in nearby streets. Typically, the houses have been built in traditional styles and materials, but many have been altered and extended over the years. This creates a more confused townscape, although the changes have no doubt benefitted the householders, by creating extra floorspace. 5. The alterations include cases where additional space has evidently been created at roof level, and the roof pitches are not consistent along the road frontages. In Appeal Decision: APP/R5510/D/25/3366468 2 some cases, the changes have had a modernising effect, in terms of architectural style, and the streetscene is by no mean uniform. 6. Like others, number 26 Mount Pleasant is a two-storey detached house. It has rendered exterior walls under a hipped main roof and has retained its original character, even though the original design appears to have been altered and extended. The front garden includes space for car parking, together with some attractive greenery. 7. It is now proposed to undertake a substantial scheme of alterations and extensions to the house, including hip-to-gable roof extensions, the addition of a large rear dormer and an alteration to the first-floor hipped roof to create a flat roof (also at the rear). 8. The ‘National Planning Policy Framework’ emphasises the aim of “achieving well designed places” in the broadest sense (notably at Section 12), while making effective use of land and encouraging economic activity. It is aimed at achieving good design standards generally, by adding to the overall quality of the area and being visually attractive and sympathetic to local character and history, although it is also recognised that appropriate change may include increased densities. The achievement of good design includes protecting existing residential amenities and providing good standards of accommodation in new development. 9. Policies in the Development Plan reflect these general planning principles, notably Policies in ‘The London Plan 2021’), and in the ‘Local Plan: Part 1 Strategic Policies’ (adopted in November 2012) and the ‘London Borough of Hillingdon Local Plan Part 2 Development Management Policies’ (adopted in January 2020). Policies D3, D4 and D6 of ‘The London Plan’ stress the importance of good design in new development, while attention is drawn to Policies BE1 and DMHB 11 in the Local Plan, which address design issues. Policy DMHD 1 in the Local Plan is specifically concerned with proposals for “Alterations and Extensions to Residential Dwellings”. 10. On the front elevation of the existing house, the proposed alterations and extensions would create a new design that would significantly change the appearance of the existing house. A new architectural form need not be ruled out in principle, however, and the new front elevation in itself would not be unacceptable, bearing in mind the context. 11. On the other hand, the extensions and alterations as a whole would be clumsy and awkward. The new flat roof at second floor level and the large box-shaped dormer extension across almost the whole width of the rear elevation would be ungainly and out of keeping with the host building, while the side elevations would also have an undesirable impact on the streetscene, even though views of these elevations from the highway would be limited. I am convinced, therefore, that the proposed development as a whole would have a harmful effect on the character and appearance of the host building and its surroundings. 12. Reference has been made to permitted development rights for householders but the scope for extensions under permitted development rights has not been clearly defined in relation to this appeal and it is not possible to give significant weight in this appeal to any “fallback” proposal. Appeal Decision: APP/R5510/D/25/3366468 3 13. Turning to the second issue in the appeal, it has been pointed out that “Bedroom 2” on the application drawing would be lit by two roof-windows, rather than by a conventional window. Such windows are not uncommon, however, and the restrictive effect that they may have on the outlook from the bedroom would not be so serious, in my opinion, as to justify the refusal of planning permission. 14. In any case, it has been pointed out that the proposed layout of the attic floor could be modified to create a single bedroom at this level, which would clearly overcome the objection. 15. Evidently, the appeal site lies within an established urban area, which is “sustainable” in planning terms, and the proposed development would make a useful addition to the existing house. Nevertheless, I am convinced that the harm that would be done to the character and appearance of the existing house and its surroundings outweigh the benefits of the project. Hence, I have concluded that the scheme before me would conflict with both national and local planning policies (including the Development Plan) and that it ought not to be allowed. Although I have considered all the matters that have been raised in the representations, I have found nothing to cause me to alter my decision. 16. In reaching these conclusions I have considered whether the appeal could be allowed but subject to conditions that might overcome the visual concerns that I have identified, to achieve a satisfactory architectural solution. In view of all the uncertainties involved, however, I have formed the opinion that it would not be possible to frame precise conditions to deal with the objections that I have identified and that therefore the appeal must be dismissed. Roger C. Shrimplin INSPECTOR