Erection of a rear roof extension with hip to gable conversion and front roof windows to the house, removal of chimney, demolition of rear conservatory and side garage, erection of a ground floor side and rear extension, erection of a front porch

Appeal Decision Site Visit on 6 August 2026 by Finlay Bradford BA (Hons) MRTPI Decision by Paul Thompson DipTRP MAUD MRTPI an Inspector appointed by the Secretary of State Decision date: 11 September 2026 Appeal Ref: 6009759 72 Arnold Crescent, Isleworth, Hounslow TW7 7NU • 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 Ian John Tonkin against the decision of the Council of the London Borough of Hounslow. • The application Ref is P/2026/0530. • The development proposed was originally described as the “erection of a rear roof extension with hip to gable conversion and front roof windows to the house, removal of chimney, demolition of rear conservatory and side garage, erection of a ground floor side and rear extension, erection of a front porch”. Decision 1. The appeal is allowed and planning permission is granted for the demolition of a rear conservatory and side garage and the erection of a ground floor side and rear extension and a front porch at 72 Arnold Crescent, Isleworth, Hounslow TW7 7NU in accordance with the terms of the application, Ref P/2026/0530, 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: Location Plan and TSL/IAN/EXT/02, 03, 05, and 07. 3) The materials to be used in the construction of the external surfaces of the extension shall match those used in the existing dwelling. 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 3. During my site visit, I observed that the chimney had been removed and that the rear roof extension, including the hip-to-gable conversion, had been completed. The parties agree that these works are permitted development, as confirmed by Certificate of Lawfulness ref. P/2025/3702. As these works have already been undertaken and are lawful, they no longer comprise a fallback position requiring consideration. Furthermore, as they do not form part of the development now proposed, it is unnecessary for me to consider them in the determination of this appeal. Accordingly, the description of development has been amended to remove Appeal Decision 6009759 2 these elements, amongst others not constituting development, in the interests of accuracy and clarity. Main Issue 4. With regard to the reasons set out within the Preliminary Matters, the main issue is the effect of the proposed ground floor side and rear extension, and front porch on the character and appearance of the host dwelling and surrounding area. Reasons for the Recommendation 5. Arnold Crescent is characterised predominantly by semi-detached dwellings of a similar design, scale and roof form. Whilst many properties have been altered and extended over time, including the addition of side extensions and front porches of varying designs and scales, there remains an observable uniformity to the appearance and massing of development which contributes positively to the character of the area. The appeal site comprises a semi-detached dwelling which, aside from the hip-to-gable roof extension, remains largely uniform in appearance with its attached neighbour and within the wider development pattern. The dwelling is set forward of the neighbouring property to its opposite side, resulting in a staggered building line and the exposure of a portion of the host’s side elevation. 6. The rear extension would exceed the advised maximum depth set out within the Residential Extension Guidelines SPD (2024) (SPD). However, the primary function of this limitation is to protect the living conditions of neighbouring occupants with regard to light and outlook, an issue which is not raised by the Council. 7. In any event, I observed several rear extensions of a similar depth to the proposed development. Where these were smaller, they were not appreciably so nor to an extent of which their effect to the character and appearance would be materially different to that proposed. Furthermore, the rear extension would be similar in depth to the rear structure on the attached neighbouring property. Accordingly, the scale of proposed rear extension would not appear incongruous to the host dwelling or surrounding area. 8. The SPD sets out that side extensions should be set back by a minimum of 1m to, amongst other things, allow the original proportions of the dwelling to remain prominent. The side elevation of the dwelling is highly visible and the proposed side extension would not be set back from the front elevation. However, its single-storey scale and proportions would ensure that the original dwelling would continue to be appreciated and therefore prominent in relation to it. 9. The proposed front porch would project beyond the existing bay window. However, it would not appear incongruous or dominant in relation to the dwelling or the surrounding area. I note that the Council reached a similar finding that its scale would be acceptable. While the porch would not strictly be consistent with the advice set out in the SPD, I am mindful that the area is characterised by porches that project beyond bay windows and, in any event, the bay window would remain a prominent element of the dwelling’s front elevation. 10. For these reasons the proposed ground floor side and rear extension, and front porch would not have a harmful effect on the character and appearance of the host dwelling and the surrounding area. Hence, the proposals would not conflict with Policies CC1, CC2, and SC7 of the of the London Borough of Hounslow Local Plan Appeal Decision 6009759 3 2015-2030 which, among other things, aim to ensure seek to ensure that extensions and alterations respond sensitively to their context, remain subordinate to the host dwelling, and preserve or enhance the established character and appearance of the street scene through high-quality design. Conditions 11. In addition to the standard time limit condition, I recommend a condition requiring that the development is carried out in accordance with the approved plans. This is necessary for enforcement purposes. I also recommend a condition requiring that the external materials match those of the existing dwellings, in the interests of the character and appearance of the area. Conclusion and Recommendation 12. For the reasons given above, I recommend that the appeal should be allowed, subject to the conditions set out above. Finlay Bradford APPEAL PLANNING OFFICER Inspector’s Decision 13. I have considered all the submitted evidence and my representative’s report and on that basis the appeal is allowed. Paul Thompson INSPECTOR