Dormer extension infill to existing roof terrace area

Appeal Decision Site visit made on 9 November 2020 by P. D. Biggers BSc Hons MRTPI an Inspector appointed by the Secretary of State Decision date: 14 December 2020 Appeal Ref: APP/N5090/D/20/3254143 160 Hendon Lane, Finchley, London N3 3PS. • 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 Salih against the decision of the London Borough of Barnet Council. • The application Ref 19/6258/HSE, dated 31 October 2019, was refused by notice dated 6 April 2020. • The development proposed is dormer extension infill to existing roof terrace area. Decision 1. The appeal is dismissed. Main Issue 2. The main issue is the effect of the proposed development on the character and appearance of the host property and the surroundings of Hendon Lane and Broughton Avenue. Reasons 3. The appeal property is located on the north side of Hendon Lane and is one of a number of large, traditionally designed houses on this section of the road. It is a substantial, semi-detached 2 storey property built in brick with half-timber detailing to the front with existing accommodation in the roof space. It is proposed to extend the accommodation at loft level by extending the existing rear and side box dormers to incorporate an existing roof terrace on the rear/side corner of the property. 4. I acknowledge from the evidence supplied and from viewing neighbouring properties from the existing roof terrace that, in some cases, the conversion of the loft space in the neighbourhood has involved the use of large box dormers. However, from my observations on site, by and large this has been achieved discretely and large box dormers are generally contained on the rear elevations of the properties. They generally do not wrap around the roof of the properties in the manner proposed on the appeal property. Consequently, the existence of dormer roof extensions elsewhere in the area would not provide a robust justification for the appeal proposal and the proposal at No 160 would still have to be acceptable in its own right. 5. In respect of the proposals at No 160, the loft extension would extend out over the roof terrace to complete a ‘wrap-around’ dormer that would extend across virtually the whole of the rear roof slope and across more than half the depth of the side roof slope. The existing dormer roof extension on the property is a bulky, dominant structure at the top of the house and the proposal would simply add Appeal Decision APP/N5090/D/20/3254143 2 further unattractive mass, bulk and depth to this. It has been put to me that building over the terrace and aligning the extension with the existing dormer would allow the inclusion of a small hipped section of roof over the first floor rear offshoot improving the current form. Whilst this would echoe the hipped gable over the rear offshoot to No 160’s semi-detached neighbour, what is proposed would be much smaller and would appear insubstantial by comparison and would appear incongruous set against the large and overbearing box dormer. I acknowledge that there would be some benefit from a better alignment of the windows in the proposed dormer with those in the first floor below but this marginal benefit would not justify the additional mass and depth of the proposed extension. 6. Although the existing roof extension has destroyed any symmetry at roof level with the semi-detached partner property at No 158 this is not a reason for the appeal proposal to further harm the character and appearance of the two properties by adding bulk and mass on one half at a high level. 7. Moreover, the adverse impact of the wrap around dormer would not be restricted to the semi-detached properties themselves. There are inward views from Broughton Avenue and an oblique view of the extended side dormer from Hendon Lane in the gap between Nos 160 and 162. From these viewpoints the proposed wrap-around extension to the dormer would add significant scale, mass and depth at a high level to an already inappropriate roof extension and appear unduly dominant. It would significantly and adversely worsen the appearance of a top- heavy roofscape. It has been put to me that the building is not listed nor is it in a Conservation Area however this does not mean that further extension to this property in an inappropriate manner would be acceptable. 8. The National Planning Policy Framework (the Framework) at paragraph 127 requires that developments must be visually attractive and sympathetic to local character to create high quality buildings and spaces amongst other things and in these respects the proposal fails. The Barnet Local Plan Core Strategy at Policy CS5 reflects the Framework in requiring development to respect local context and local character. Similarly, the Barnet Local Plan Development Management Policies at Policy DM01 requires proposals to preserve local character and respect the appearance, scale, mass, height and pattern of surrounding buildings, spaces and streets. For the above reasons the design of the proposed extension would conflict with these policies. 9. To assist in the implementation of these design policies the Council has produced the Barnet Residential Design Guide (BRDG) which provides guidance for householders considering extensions including dormer roof extensions. The guide makes it clear that this type of extension whilst adding accommodation can have a significant impact on character and requires careful handling. The guide requires that they should not wrap around a hipped roof, should be subordinate to the roof form and not occupy more than half the width or half the depth of a roof slope. They should be set up from the eaves, down from the ridge and inset from the party wall. The dormer should be proportionate to the rest of the house by being no wider than the window below it and with minimal side cheeks. The advice in the BRDG is already breached in almost all respects by the existing box dormers and the appeal proposal together with the existing would result in cumulative additional harm. 10. For the reasons above, the design objectives of Policies CS5, DM01 and the BRDG would not therefore be achieved by this proposal and it would be unacceptable in terms of the impacts on the character and appearance of No 160 itself as the host dwelling and of the surroundings on Hendon Lane and Broughton Avenue. Appeal Decision APP/N5090/D/20/3254143 3 Other Matters 11. I have had regard to the Public Sector Equality Duty contained in the Equality Act 2010 and understand the appellant’s wish to provide extended and improved loft- level accommodation and that in doing so he is seeking to make sustainable and effective use of an existing dwelling, an objective which is encouraged by the Framework in Section 11. I acknowledge that this national policy objective makes the principle of extending existing houses acceptable. However, paragraph 122 in the same section of the Framework states that this should not be at the expense of maintaining an area’s prevailing character and setting. Sustainable and effective use of the dwelling would not therefore outweigh the harm to the character and appearance as a result of the proposal or justify an exception to policies and guidance in this case. Conclusion 12. In reaching my decision I have had regard to the matters before me but for the reasons above the appeal should be dismissed. P. D. Biggers INSPECTOR