Part single, part two storey side and rear extensions including conversion of existing garage into habitable room and first floor Juliette balcony and new rear patio area. Two storey front extension incorporating new front porch. Associated alterations and extensions to roof including increasing ridge height to create a new crown roof with 2no. rear dormer windows and 1no. dormer window to both side elevations, 3no. rooflights to front roofslope and 2no

Appeal Decision Site visit made on 8 April 2026 By Terrence Kemmann-Lane JP DipTP FRTPI MCMI an Inspector appointed by the Secretary of State Decision date: 21 April 2026 Appeal Ref: 6004391 3 Grosvenor Gardens, London, NW11 0HH • 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 Vogel against the decision of Barnet London Borough Council. • The application Ref is 25/3963/HSE. • The development proposed is part single, part two storey side and rear extensions including conversion of existing garage into habitable room and first floor Juliette balcony and new rear patio area. Two storey front extension incorporating new front porch. Associated alterations and extensions to roof including increasing ridge height to create a new crown roof with 2no. rear dormer windows and 1no. dormer window to both side elevations, 3no. rooflights to front roofslope and 2no. rooflights to both side roofslopes. Decision 1. The appeal is allowed and planning permission is granted for part single, part two storey side and rear extensions including conversion of existing garage into habitable room and first floor Juliette balcony and new rear patio area. Two storey front extension incorporating new front porch. Associated alterations and extensions to roof including increasing ridge height to create a new crown roof with 2no. rear dormer windows and 1no. dormer window to both side elevations, 3no. rooflights to front roofslope and 2no. rooflights to both side roofslopes at 3 Grosvenor Gardens, London, NW11 0HH in accordance with the terms of the application, Ref 25/3963/HSE, subject to the conditions set out in the schedule at the end of this decision. Preliminary matter 2. The planning application described the development as “Part single part two storey side and rear extensions. New crown roof with side and rear dormers and accommodation in the roof space”. By agreement this was changed to the description given in the banner heading above: it more accurately details the nature of the proposed development. Main Issues 3. The main issues in this case are: i) the effect of the proposed ground floor rear extension on the character of the host property, the street scene and the locality; ii) the effect of the proposed ground floor rear extension on the living conditions of the neighbouring occupiers at No.5 Grosvenor Gardens in respect of loss of outlook, increased sense of enclosure and potential loss of light and overshadowing. Appeal Decision 6004391 2 Reasons 4. The appeal site is a 2-storey detached house located on the west side of Grosvenor Gardens, close to the junction with Cranbourne Gardens. The surrounding area is developed by substantial family houses, both detached and semi-detached, most of which have been enlarged or altered significantly over time. The appeal property sits adjacent to No.5 Grosvenor Gardens, which I noted at my site visit is of a similar original scale and age as the appeal property, but has been extended and altered, such that it is now considerably larger than No.3. 5. The description of the development, set out in the banner heading above, covers various extensions and alterations, a number of which are not controversial. To simplify this decision, I will set out these elements. The first-floor rear element would have a depth within the 3m stipulation, and incorporate a crown roof, complying with paragraphs 14.23 and 14.26 of the Residential Design Guidance Supplementary Planning Document (adopted October 2016) (RDG). The single storey side element along the southwestern boundary with a width of 0.7m is less than half the width of the dwellinghouse and therefore acceptable. The proposed rear patio area is acceptable, as a large garden space will still remain and it would not appear out of character. A central two-storey front porch extension with a gable roof with a depth of 0.8m and a width of 2.4m, would not be contrary to the existing architectural features such as bay windows, and would comply with paragraphs 14.28 and 14.29 of the RDG. 6. The conversion of the existing garage into a habitable room, with the garage door being replaced with a bay window that continues upwards, incorporated with the proposed first floor side front extension, would achieve a satisfactory balance to the proposed front elevation. As to the proposed roof extension, given the precedent of the approved crown roof and dormer extension at the adjoining No.5 Grosvenor Gardens, that the dormers would be less than half the width of the roof slope that they would sit on and that roof extensions varying in design and scale are commonly seen in Grosvenor Gardens, these elements of the proposal would not appear out of character with the streetscene. 7. The remaining elements that are the subject of the refusal reasons, the proposed first floor side/front extension and the ground floor rear extensions, must now be considered. The former would have a depth of 5.2m and a width of 3.7m, which is less than half the width of the dwellinghouse, but there would not be a setback of 1m from the front building line of the existing dwelling, with the new bay window protruding beyond the established front building line. In addition, there would only be a gap of 0.7m from the side boundary, which is less than 1m, and no set down from the ridge height due to the changes proposed to the main roof form, contrary to paragraphs 14.15 and 14.17 of the RDG. 8. However, when seen in the context of the variety of alterations and extensions proposed, and the general character of Grosvenor Gardens, including those that have recently been approved by the council, the proposed first floor side/front extension, taken in the context of the totality of the proposal before me, is acceptable in achieving a coherent whole. Furthermore, the gap of 0.7m on the side boundary does not come nearer to the boundary than the existing house. 9. The rear ground floor extensions, do not meet the requirements of paragraph 14.21 of Barnet's Residential Design Guidance (RDG) which states that the depth of a Appeal Decision 6004391 3 single storey rear extension, normally considered acceptable for a detached property, is 4 metres. The proposed ground floor rear element would have a depth ranging from 4.8 metres to 6.8 metres, which significantly exceeds the recommended depth in the RDG. 10. However, there is a prior approval for a "Single storey rear extension with a depth of 6.8m, a maximum height of 4m and an eaves height of 3m, following the demolition of the existing rear extension". The council contends that this does not amount to a fallback position as the current proposal introduces additional footprint of a 4.8m deep ground floor rear extension, along the southwestern side of the rear wall, together with the introduction of a lantern rooflight. The introduction of a lantern rooflight leads to the maximum height being 4.6m and therefore exceeds the measurements under the prior approval. I do not regard it as being objectionable in itself, and the fact that it does not come within the ambit of prior approval is not of significance when the entire proposal comes within the consideration of an application for full planning permission. The lantern roof light would not appear out of place or affect neighbours. 11. The proposed additional 4.8m deep single storey ground floor rear extension along the side towards No.5 Grosvenor Gardens, did not feature in the scheme with prior approval, but it would not have an impact on the character of the host property when seen within the totality of the scheme. 12. The conclusions above leave the separate issue of the effect of the proposed ground floor rear extension, just mentioned, on the living conditions of the neighbouring occupiers at No.5 Grosvenor Gardens in respect of loss of outlook, increased sense of enclosure and potential loss of light and overshadowing to be considered. As the officer’s report points out, the rear building lines of properties on Grosvenor Gardens are staggered. The rear building line of the appeal site protrudes further than No.5 into the rear garden by 2.2m as existing. The implementation of the 4.8m deep ground floor rear extension along the shared boundary would lead to a perceived 7m deep extension. I agree that this would have a material impact on the living conditions of the occupiers of No.5. 13. However, the appellant’s appeal statement informs me that a new prior approval application (council reference25/5051/PNH) resulted in the council determining that prior approval was not required. This satisfies me that this element of this appeal proposal meets the provisions of The Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2, Part 1, Class, and that the implications of the rear single storey extension on the occupiers of No.5 do not prevent or override the conclusion that the proposal before me is acceptable. In light of all the considerations referred to in this decision, the appeal will be allowed. Conditions 14. The statutory condition that provides a time limit on the start of development must be imposed. In addition, the council has suggested a number of conditions in the event that the appeal is upheld. I have considered these in the light of Planning Practice Guidance (PPG). For clarity and to ensure compliance with the PPG, I have amended some of the text. I consider that the conditions should be imposed for the following reasons: condition 2 is required for certainty and avoidance of doubt as to the development permitted; condition 3 is to ensure that the Appeal Decision 6004391 4 development relates appropriately to the existing house; and conditions 4, 5 and 6 are to ensure that the amenities of the occupiers of adjoining properties are not prejudiced by overlooking. Terrence Kemmann-Lane INSPECTOR SCHEDULE of 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: 2509-NMP-XX-00-DR-B-00002 Revision P1 2509-NMP-XX-00-DR-B-00100 Revision P1 2509-NMP-XX-00-DR-B-00101 Revision P1 2509-NMP-XX-00-DR-B-00200 Revision P1 2509-NMP-XX-00-DR-B-00201 Revision P1 2509-NMP-XX-ZZ-DR-B-00300 Revision P1 2509-NMP-XX-ZZ-DR-A-20002 Revision P1 2509-NMP-XX-ZZ-DR-A-20100 Revision P1 2509-NMP-XX-ZZ-DR-A-20101 Revision P1 2509-NMP-XX-ZZ-DR-A-20200 Revision P1 2509-NMP-XX-ZZ-DR-A-20201 Revision P1 2509-NMP-XX-ZZ-DR-A-20300 Revision P1 Location Plan 3) The materials to be used in the external surfaces of the building shall match those used in the existing building. 4) The roof of the extension hereby permitted shall only be used in connection with the repair and maintenance of the building and shall at no time be converted to or used as a balcony, roof garden or similar amenity or sitting out area. 5) Before the building hereby permitted is first occupied the proposed window(s) in the side elevations facing Nos.1 and 5 Grosvenor Gardens shall be glazed with obscure glass only and shall be permanently fixed shut with only a fanlight opening and shall be permanently retained as such thereafter. 6) Notwithstanding the provisions of any development order made under Section 59 of the Town and Country Planning Act 1990 (or any Order revoking and re-enacting that Order) no windows or doors, other than those expressly authorised by this permission, shall be placed at any time in the side elevation(s), of the extension(s) hereby approved, facing Nos.1 and 5 Grosvenor Gardens. End of Schedule