First floor side extension; a 2-storey rear extension; conversion of roofspace to habitable accommodation with two rear dormers and 4 x side-facing conservation rooflights; and, installation of new side elevation windows and associated alterations to the rear fenestration including Juliette balcony at first floor level

Appeal Decision Site Visit made on 12 October 2020 by Andrew Parkin BA (Hons) DipTP MRTPI an Inspector appointed by the Secretary of State Decision date: 28 October 2020 Appeal Ref: APP/N1920/D/20/3256205 16 The Comyns, Bushey Heath WD23 1HP • 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 & Mrs O Shea against the decision of Hertsmere Borough Council. • The application Ref 20/0207/HSE, dated 12 February 2020, was refused by notice dated 1 May 2020. • The development proposed is a first floor side extension; a 2-storey rear extension; conversion of roofspace to habitable accommodation with two rear dormers and 4 x side-facing conservation rooflights; and, installation of new side elevation windows and associated alterations to the rear fenestration including Juliette balcony at first floor level. Decision 1. The appeal is dismissed. Main Issue 2. The main issue is the effect of the proposal on the character and appearance of the area, including the significance of The Lake, Bushey Heath Conservation Area (TLBHCA). Reasons 3. The appeal property is a 2-storey dwelling on the Warren Estate, which comprises 77 detached dwellings constructed in the mid-20th century in the traditional English country house style. Whilst there is a consistent design theme to the Estate, a number of different designs for dwellings have been used. The appeal building is a Woodcote design, which has a noticeably wider front than depth and includes a catslide roof over the integral garage. 4. TLBHCA includes the Estate together with some buildings to the northeast by the High Road and was designated in 1998. TLBHCA is a designated heritage asset and its significance in this area derives in part from the design and materials of the dwellings it contains, together with the spaces around them, including gardens and streets. The topography of the area slopes downwards, away from the High Road, including along that part of The Comyns containing the appeal building. Appeal Decision APP/N1920/D/20/3256205 2 5. Some of the dwellings on the Estate have been extended or altered, including in the vicinity of the appeal building1. However, the appeal building itself is substantively unchanged and makes a positive contribution to the character and appearance of the area and to the significance of TLBHCA. 6. The proposed development would significantly extend the appeal dwelling to the side / rear. The insertion of a first floor side extension to the catslide roof, the introduction of two crown roofs, and the additional fenestration to the roofscape, would be significant changes to the appearance of the building. 7. Whilst the proposed works would be to the rear of the existing roof ridgeline, the proposed first floor side extension, including its crown roof, would be readily visible from The Comyns, in particular in views from the front and southwest. Furthermore, the side extension on the catslide roof would erode the sky gap2 between Nos 16 and 18 at first floor level, through which woodland to the rear is visible. 8. The 2-storey extension to the rear, which is contiguous to the first floor side extension, would also be visible in views from the southwest, and to a lesser extent from the northeast due to screening vegetation and the position of No 14 next door. 9. I note the appellant’s comments regarding the similarity of the appeal proposal with the approved schemes at Nos 12 and 14 in particular, given their proximity to No 16 on The Comyns. From the limited evidence before me and my observations on site, these extensions seem generally similar and there are some commonalities with the appeal proposal. However, I am not fully familiar with these schemes. 10. Nos 12 and 14 are both Dorchester-type dwellings, different to the appeal building. The Council approved both proposals but reached different conclusions as to their acceptability. The Council concluded that the first scheme, at No 143, would have an acceptable impact in terms of the character and appearance of the area. However, the subsequent scheme, at No 124, would cause less than substantial harm to the significance of TLBHCA, but that the identified public benefits would outweigh this harm. 11. In light of this, the Council’s reference to ‘the cumulative harm caused by extensions at neighbouring properties5’ in its reason for refusal is somewhat confused. However, as the appellant notes, each proposal should be determined on its individual merits, which is what I have done in this case. 12. I have had regard to the statutory duties under Section 72 (1) of the Planning (Listed Buildings and Conservation Areas) Act 1990, which requires decision makers (amongst other things) to have special regard to the desirability of preserving or enhancing the character or appearance of a Conservation Area. 13. Aspects of the proposed design respond to the existing dwelling, including in terms of materials. The crown roofs are said to be needed to match the angle of the proposed and existing roofslopes and so retain the architectural 1 Nos 12, 14 and 31 The Comyns. 2 Paragraph 7.4 of the Warren Estate, Bushey Heath Design Guide September 2003 (WEBHDG). 3 LPA Ref. 17/0852/HSE that was granted planning permission on 18 July 2017. 4 LPA Ref. 19/1702/HSE that was granted planning permission on 19 December 2019. 5 Whilst the properties are not specified on the Decision Notice , from the officer report it seems that they are Nos 12 and 14. Appeal Decision APP/N1920/D/20/3256205 3 appearance of the building. I also note the suggestion that their visual impact could be mitigated by way of ridge tiles and that there are examples elsewhere on the Estate of crown roofs. 14. Nevertheless, the proposed development would fundamentally change the appearance of the appeal building, substantially increasing its depth and massing. The proposed works would be visible in views along this part of The Comyns and would curtail the spaces between the next door dwellings at roof level. 15. Notwithstanding some similarities with the extensions at Nos 12 and 14, the proposal would be a visually prominent and disproportionate addition to No 16, which would be unsympathetic to its original design and harmful to the streetscene. It would, therefore, detract from the character and appearance of the host building and the wider area and would cause less than substantial harm to a designated heritage asset. 16. Paragraph 193 of the National Planning Policy Framework 2019 (the Framework), requires great weight to be given to the conservation of a designated heritage asset. The only suggested public benefit of the proposal would be the short-term employment associated with the development works, which is predominantly a private benefit to the employees involved. Therefore, with reference to paragraph 196 of the Framework, this less than substantial harm to a designated heritage asset is not outweighed. 17. For these reasons the proposed development would adversely affect the character and appearance of the area, including the significance of TLBHCA. Consequently, it would conflict with Policies SP1 (creating sustainable development), CS14 (protection or enhancement of heritage assets) and CS22 (securing a high quality and accessible environment) of the Hertsmere Local Plan Core Strategy 2013; Policies SADM29 (heritage assets) and SADM30 (design principles) of the Hertsmere Local Plan Site Allocations and Development Management Policies Plan 2016; and, with guidance contained in the WEBHDG and the Framework. Conclusion 18. The proposal would conflict with the development plan as a whole and there are no material considerations that would cause me to determine this appeal otherwise than in accordance with the development plan. 19. For the reasons given above, and taking into account all matters raised, I conclude that the appeal is dismissed. Andrew Parkin INSPECTOR