Alterations and part demolition including formation of new openings and new mansard extensions to side wing, ‘rear conservatory extensions’ and extensions at lower ground floor level

Appeal Decision Site visit made on 25 February 2020 by S Thomas BSc (hons) MSc MRTPI an Inspector appointed by the Secretary of State Decision date: 07 July 2020 Appeal Ref: APP/K5600/D/19/3243707 23 Tregunter Road, London SW10 9LS • 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 M Herbst against the decision of The Council of The Royal Borough of Kensington & Chelsea. • The application Ref PP/19/06200, dated 6 September 2019, was refused by notice dated 8 November 2019. • The development proposed is alterations and part demolition including formation of new openings and new mansard extensions to side wing, ‘rear conservatory extensions’ and extensions at lower ground floor level. Decision 1. The appeal is dismissed. Preliminary Matter 2. As the proposal is in a conservation area, I have had special regard to section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (the Act) which requires special attention to be had to the desirability of preserving or enhancing the character or appearance of a Conservation Area. Main Issue 3. The main issue is whether the proposal would preserve or enhance the character or appearance of the Boltons Conservation Area (CA) including the effect on the existing building. Reasons 4. The appeal property is a semi-detached building of Victorian villa appearance with an attached side wing. It is located in a prominent position along Tregunter Road opposite the junction with Little Boltons. Given its position it is a focal building in the street scene when viewed from Little Boltons. The architectural qualities of the built environment in this area including the appeal property, contributes to a pleasant and attractive townscape. 5. The property is unique along Tregunter Road in that it has an attached wing formed with balustrade which is wider than the main part of property but sits at a lower height. The unique design of this side wing and variation in character with the bottle balustrade feature contributes to the property’s interest in the street scene. As the side wing is at a lower height this allows views through the Appeal Decisions APP/K5600/D/19/3243707 2 balustrade and over it to the trees and buildings beyond and this contributes to making the side wing appear visually subservient to the main part of the property. I found that views of the buildings to be of significant interest within the street scene on my visit. Whilst I recognise that views will change dependant on the leaf coverage of the trees, nevertheless this viewpoint makes a key contribution to the character of the area. 6. The CA is defined by the high-quality townscape and built environment which together with its tree planting contributes to the character of the CA. The Boltons Conservation Area Appraisal (CAA) (2015) identifies the appeal building as one which makes a positive contribution to the architectural character and appearance of the CA and such buildings are key reasons for its designation and significance. It states that unsympathetic alterations will normally be resisted. Tregunter Road is characterised by individually designed pairs of classically inspired villas and the CAA identifies the property as having a historic pitched roof which are part of the distinctive features of the properties, with original roof forms making a strong positive contribution to the character of the CA. In addition, the CAA identifies the property as within an important view in the CA, as one of a number of welcome end stops within the townscape. Given the above, I find that the significance of the CA, insofar as it relates to this appeal, to be primarily associated with the architectural quality of the buildings, roofscapes and important views. 7. I would agree with the Councils assessment that the rear extensions to the ground floor and below, are subordinate, modest and sympathetic to the character of the existing building and would be acceptable additions to it. In addition, the proposed rooflights to the rear and lanterns are also acceptable and would not harm the character of the building. I turn now to the proposed mansard roof extension and proposed alterations to the front elevation. 8. The proposed mansard roof would raise the existing roof height of the side wing and would markedly change the relationship of the side wing with the original building. Whilst the height of the roof would sit below the eaves of the main part of the house, the lowering of the balustrade would have the unfortunate effect of increasing the prominence of the mansard roof. This would lead to it becoming a dominant feature of the property and thus causing the side wing to no longer appear subservient to the main part of the dwelling. 9. The steeply sloping mansard roof would have a more dominant appearance than the gently sloping pitched roof of the main part of the house and would contrast sharply with it and appear bulky alongside it in the street scene. In addition, the large window proposed in the roof would increase its dominance, which I consider would have a more imposing effect than the slimmer window initially proposed in the visual representations in the Design and Access Statement (DAS). The lowering of the balustrade to allow for the mansard roof would also alter the appearance of the existing side extension making it appear compressed which would harm its appearance. 10. Whilst I acknowledge the mansard roof proposes a simple design and the use of slate in an attempt to make it appear subservient against the pale coloured stucco façade of the main house, given its form, height, slope of the roof and window this would not effectively mitigate its impact. In addition, I recognise that the proposal would reinstate part the bottle balustrade feature however I consider its effect will be severely diminished with the mansard roof behind it. Appeal Decisions APP/K5600/D/19/3243707 3 11. I recognise mansard roofs may be a feature in the wider area, however they are not a feature along Tregunter Road and would be uncharacteristic of roofscapes in the immediate street scene. Given the existing roof forms the proposal would not integrate effectively into the street scene and would appear visually intrusive in this key viewpoint in the CA. 12. Notwithstanding the harm to the building it would represent a negative effect on the key view along Little Bolton’s and the mansard would severely diminish the views through and over the existing parapet to the historic buildings beyond. This would cause harm to the wider CA. Whilst I accept that the buildings could be seen further north along Little Boltons they will still be framed by the mansard roof which would be an unacceptable addition to the street scene. 13. Furthermore, whilst the window arrangement retains a sense of verticality, the large replacement bay window to the ground floor adds to the dominance of the enlarged side wing compared to the smaller windows of the main part of the dwelling. Whilst I acknowledge there is no change to the entrance to the property, significantly, the combination of the proposed large mansard roof together with the large window changes the character of this current subordinate side wing and would give the appearance of a separate attached dwelling, crammed into the plot. The images in the Design and Access Statement confirm my view on this. This would appear visually incongruent in the important views of the property from Little Boltons. Whilst I note that the size of the ground floor window could be conditioned, given the dominant effect of the mansard roof I do not consider a smaller window would effectively mitigate the harm that would be caused. 14. Paragraph 193 of the National Planning Policy Framework (the Framework) advises that when considering the impact of development on the significance of designated heritage assets, great weight should be given to their conservation. Paragraph 194 goes on to advise that significance can be harmed or lost through the alteration or destruction of those assets and that this should have a clear and convincing justification. The proposed mansard extension would harm the appearance of this building which contributes to the character and significance of the CA and would negatively impact on a key view in the CA, and considering this I find the harm to be less than substantial in this instance but nevertheless of considerable importance and weight. 15. The Framework says that such harm should be weighed against the public benefits of the proposal and that great weight should be given to the asset’s conservation. I acknowledge the scheme includes a number of improvements that would improve the appearance of the frontage of the dwelling and within the important view from Little Boltons which would constitute a public benefit. 16. I acknowledge that the proposed removal of the bottle balustrade above the entrance door is to enhance the ancillary relationship of the side wing extension with the main house, however I find the bottle balustrade running up to the boundary an unusual and interesting feature in the street scene which contributes to the character of the townscape. The views through this add significant interest to the street scene and therefore I am not persuaded this would amount to a benefit. 17. I recognise however that the proposal would include improvements to the front of the property that I consider would amount to a heritage benefit. The existing Appeal Decisions APP/K5600/D/19/3243707 4 mechanical gate is currently stark and exposes the front elevation to the street scene which is not complimentary to the existing character of the area. The proposed replacement gate incorporating a false dwarf wall would improve the appearance of the frontage of the dwelling tying it into adjacent boundary treatments and harmonising it with the existing character of the street scene. This would result in a benefit to the character and appearance of the CA. Furthermore, whilst I have found harm with the large bay window, I do acknowledge that the adjustment in height of the existing windows to tie in with the main house would improve the appearance of the property and would lead to a benefit. However, these public benefits would not outweigh the harm caused by the mansard roof extension to the appearance of the dwelling and to the character and appearance of the CA. 18. Given the above, and the fact the public benefits identified would not outweigh the harm caused, I conclude that, on balance the proposal would fail to satisfy the requirements of the Act and thus would fail to preserve the character or appearance of the CA and would be contrary to the design aims of Policies CL1, CL2, CL3, CL6, CL8, CL9 and CL11 of the Royal Borough of Kensington and Chelsea Local Plan (2019). Amongst other matters, these policies seek that developments should preserve or enhance the character and appearance of a CA, should respect the character and appearance of existing buildings, development should respect the existing context and contribute positively towards townscape through architecture addressing matters such as scale, height, mass, roofscape, bulk as well as views, roof alterations or additional storeys should be architecturally sympathetic to the age and character of buildings, extensions should be subordinate to the original building and development should protect views that contribute to the character of the area. Other Matters 19. I acknowledge that the proposal will not result in harm to the amenity of neighbouring residents, however this is a matter that would be required to be acceptable in its own right to make the development acceptable. This holds neutral weight in favour of the proposed development. I recognise that the main purpose of the alterations to the side wing, through the proposed mansard roof form is to address the change in level between the main house and the side wing and to provide additional accommodation that the family requires. Whilst I am sympathetic to the private needs of the occupiers of the dwelling, this does not outweigh the harm the proposal would cause to the character and appearance of the CA and the building. Conclusion 20. For the above reasons, the appeal is dismissed. S Thomas INSPECTOR