Erection of a mansard roof

Appeal Decision Site visit made on 8 February 2022 by Richard Newsome BA (Hons) MTP MRTPI an Inspector appointed by the Secretary of State Decision date: 25 February 2022 Appeal Ref: APP/V5570/D/21/3283944 67 Arlington Avenue, Islington, London N1 7BA • The appeal is made under section 78 of the Town and Country Planning Act 1990 against a refusal to grant planning permission. • The appeal is made by Mr Chris Tinson against the decision of Islington Borough Council. • The application Ref P2021/1879/FUL, dated 21 May 2021, was refused by notice dated 23 August 2021. • The development proposed is the erection of a mansard roof. Decision 1. The appeal is allowed and planning permission is granted for the erection of a mansard roof at 67 Arlington Avenue, Islington, London N1 7BA in accordance with the terms of the application, Ref P2021/1879/FUL, dated 21 May 2021, subject to the following conditions: 1) The development hereby permitted shall be carried out in accordance with the following approved plans: Site Plan; Location Plan; 67-Arl.Avn/Plng.109; 67-Arl.Avn/Cons.110; 67-Arl.Avn/Plng.111; 67-Arl.Avn/Plng.112; 67-Arl.Avn/Plng.113; and 67-Arl.Avn/Plng.114. 2) The flat roof area between the front parapet and the mansard roof hereby permitted shall not be used as private amenity space, with access to be only for repair or maintenance purposes, or as a means of emergency escape. Procedural Matters 2. The description of development included on the original planning application form was ‘Retrospective planning application for the Erection of a Mansard Roof.’ I have amended the description of development to remove reference to the retrospective nature of the planning application. This is because section 55 of the Town and Country Planning Act 1990 describes development as the carrying out of building operations and not their retention. However, for the avoidance of doubt, the proposal has been constructed and permission is sought retrospectively. Main Issue 3. The main issue is the effect of the mansard roof on the character and appearance of the area, including the Arlington Square Conservation Area, and the host dwelling as a non-designated heritage asset. Appeal Decision APP/V5570/D/21/3283944 2 Reasons 4. Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 requires me to pay special attention to the desirability of preserving or enhancing the character or appearance of the Arlington Square Conservation Area (the CA). In considering the significance of the CA I have had regard to the Arlington Square Conservation Area Design Guidelines (2002) (the ASCADG). 5. The CA is predominantly residential and quiet in character with spacious wide roads and a number of green spaces. The southern boundary of the CA borders the Regent’s Canal. The ASCADG describes the CA as having special architectural and historic interest due to the strong visual unity of the predominant 2-storey terraces with basements. Properties in the CA generally retain most of their external architectural features such as front boundary railings and traditional iron work. 6. The appeal property is identified by the Council as part of a locally listed terrace in its Local Heritage List (the LHL) and therefore constitutes a non- designated heritage asset. The significance of the terrace includes the retention of original features, the group value with the adjacent properties, the stucco band at first floor level, moulded window box sills to first floor, decorative cast iron window guards at ground and first floor, and original glazing bars. 7. The appeal property is a 2-storey with basement mid-terraced dwelling located close to the southern edge of the CA. It is located close to the highway and has a small rear garden. There is a modern development adjacent to the Regent’s Canal located behind the appeal property. 8. It is evident that the provision of a mansard roof at the appeal property is acceptable in principle given that the Council has granted planning permission (Ref P2020/1829/FUL) for such an extension. However, the appeal scheme before me has not been developed in accordance with that planning permission. Therefore, the parties disagree about whether the design of the appeal scheme is acceptable or not. 9. I acknowledge that both parties refer to the presence of other mansard roofs to properties in the area, in particular on Arlington Avenue. The appellant notes that planning permissions have been granted for mansard roofs at Nos 65, 69, 71, and 73. The Council notes that the mansard roofs at Nos 65 and 69 have also been constructed contrary to relevant planning permissions and also notes that whilst there are mansard roofs at Nos 47, 57, and 59 that these pre-date the Council’s Urban Design Guide Supplementary Planning Document (2017) (the SPD) and the ASCADG. I noted these mansard roofs during my site visit and whilst I do not have full details of all the relevant planning applications, I attribute moderate weight to the presence of the other approved mansard roofs in the area. 10. Whilst the proposal is marginally taller than the scheme which has planning permission, I noted on my site visit that due to the set back from the front parapet the mansard roof is not visible from Arlington Avenue. I acknowledge the Council’s observation that it is visible from the entrance to Clock Tower Mews. However, such views are very limited and only a small upper part of the mansard roof is visible. Appeal Decision APP/V5570/D/21/3283944 3 11. The modern development to the rear of Arlington Avenue also heavily restricts public views of the rear of the terrace. I noted from my site visit that there are no clear views of the rear of the appeal property from the public footpath adjacent to the Regent’s Canal. 12. I acknowledge that the construction of the proposal has affected the butterfly roof to the appeal property. However, whilst the SPD seeks to retain such features the outline of the butterfly roof profile is still evident to the rear of the property. There is a clear distinction between the extent of the host dwelling and the roof extension above. Whilst the proximity of the mansard roof to the rear elevation of the property adds some bulk to the proposal this is not substantive enough so as to result in harm to the dwelling, the area, or the CA as a whole. 13. I appreciate that the Council’s guidance in the SPD indicates that the roof slope of mansard roofs should be 72 degrees. The appellant advises that the rear roof slope of the proposal is 76 degrees, although I note that the lower part of the rear of the mansard roof elevation appears vertical before beginning to slope. Whilst the roof slope of the proposal does not conform with the precise guidance included in the SPD, I do not consider the magnitude of variance results in harm to the character and appearance of the dwelling, the terrace, or the CA. 14. The SPD states that party walls should follow the form of the roof and not include a 90 degree up stand projecting beyond the form of the roof extension to avoid unsightly protrusions. It also states that chimney stacks should only be raised where they will not disrupt the rhythm of a terrace. Whilst I acknowledge that the development heightens the party walls they do not create unsightly protrusions. Similarly, the increase in the height of the chimneys does not result in them being unduly prominent or disrupting the rhythm of the terrace. Indeed, I note that other chimneys on the same terrace are taller than those associated with the appeal property. 15. I recognise that the roof lights on the mansard roof are not flush to the roof covering as per the guidance in the SPD. However, I note that only one of the roof lights is visible, and in a limited manner, from the entrance to Clock Tower Mews. 16. I noted from my site visit that the mansard roof includes a front dormer with doors. Whilst this results in an unsymmetrical finish to the front elevation of the mansard roof this is not visible from any public vantage point. However, I acknowledge that the doors do provide access to the flat roof in front of the mansard roof. The use of this area for private amenity space for the occupants of the appeal property, including any associated domestic paraphernalia, would be obtrusive and harmful to the character and appearance of the host dwelling as a non-designated heritage asset, and the area, including the CA. I note that the appellant recognises this potential detrimental effect and has suggested the imposition of a condition to preclude the use of the roof space for such purposes. 17. Whilst I acknowledge that the appeal scheme does not comply with specific detailed elements of the guidance in the Council’s ASCADG and SPD, it does not depart significantly from the guidance. Therefore, I find that it does not result in conflict with the aims of the guidance including preserving and enhancing conservation areas. Appeal Decision APP/V5570/D/21/3283944 4 18. Overall, I conclude that given the lack of visibility of the proposal and the presence of other approved mansard roof extensions in the locality that the proposal does not harm the character and appearance of the area, including the Arlington Square Conservation Area, nor the host dwelling as a non- designated heritage asset. 19. Consequently, the proposal does not conflict with Policies D3, D4 and HC1 of The London Plan (2021); Policies CS8 and CS9 of Islington's Core Strategy (2011); Policies DM2.1 and DM2.3 of Islington's Local Plan: Development Management Policies document (2013); and the guidance contained within the ASCADG and SPD. Taken together these, amongst other things, seek to maintain the design quality of development, and to protect the heritage and character of areas, including conservation areas and non-designated heritage assets. 20. The proposal also does not conflict with the National Planning Policy Framework (the Framework), which amongst other things, requires that developments are of a high-quality of design and sympathetic to local character, and that heritage assets are conserved in a manner appropriate to their significance. Conditions 21. I note that the Council has not proposed any conditions and I have therefore considered the conditions suggested by the appellant against the tests set out in paragraph 56 of the Framework and the Planning Practice Guidance. I have not imposed a condition relating to the timescale for the commencement of development as it is not necessary due to the proposal having already been constructed. 22. I consider that a condition in respect of the development being in accordance with the approved plans is necessary for the avoidance of doubt as to what has been approved. Whilst I note the appellant has suggested listing all submitted drawings, I have only included those relating to the proposed appeal scheme. For accuracy, I have also used the references from the drawings as the references provided by the appellant differ slightly from those on the drawings. 23. I have imposed a condition to prevent the use of the flat roof in front of the mansard roof for private amenity space. This is necessary to protect the character and appearance of the area, including the CA, and the appeal property as a non-designated heritage asset. I have amended the wording of the condition proposed by the appellant for added clarity. Conclusion 24. For the reasons given I conclude that the appeal should succeed. Richard Newsome INSPECTOR