Appeal 3274491

The appeal is dismissed.

The site visit was undertaken by an Appeal Planning Officer whose recommendation is set out below and to which the Inspector has had regard before deciding the appeal.

The proposal relates to a mansard roof extension and associated works including a timber fence along the rear parapet. The Council’s substantive concerns relate to the roof extension and so the recommendation set out below will focus on the effect of the proposed mansard roof.

The Government published on 20 July 2021 a revised version of the National Planning Policy Framework (Framework). In this instance, the issues most relevant to the appeal remain unaffected by the revisions to the Framework and I am satisfied that no party would be disadvantaged by my reference to the revised Framework.

The main issue is whether the proposed development would preserve or enhance the character or appearance of the Kensington Conservation Area.

The appeal site is located within the Kensington Conservation Area where Section 72(1) of the Planning (Listed Building and Conservation Areas) Act 1990 requires that special attention is paid to the desirability of preserving or enhancing the character or appearance of conservation areas. The conservation area predominantly derives its significance from its impressive variety of historic buildings, including the appeal site and nearby properties, with Nos 101- [site address] identified as positive contributors to the conservation area within the Kensington Conservation Area Appraisal.

The appeal dwelling is the final property in a small terrace of five houses located at the northern end of [address], close to the junction with [address] Gate. The terrace is characterised by tall townhouses of similar design with bay window features and parapets. Its roofscape has undergone alterations and traditional butterfly roof forms have only been retained at the appeal dwelling and its neighbour, No 107. Where traditional roof forms have been removed, they have been replaced with roof terraces, fencing along the rear parapet and modest roof extensions. The neighbouring property to the immediate north, No 111, is both taller than, and set forward of, the appeal dwelling.

The proposed extension would be substantial in size and scale and would appear as an incongruous intervention along the historic roofline at the appeal terrace. Although other dwellings along this terrace have replaced their traditional roof forms with replacement roof extensions, these developments are more modest than the appeal scheme and are not directly comparable. The removal of the traditional butterfly roof, which contributes positively to the appearance of the host dwelling, and its replacement with a large mansard roof would be out of keeping with and harmful to the appearance of the host property and the terrace of which it forms part of. While the proposed materials reflect a consideration for the historic character of the appeal dwelling, they would not sufficiently mitigate the harm that arises from the proposal’s size, scale and overall design.

Although potential views of the proposal from nearby public vantage points would be very limited, due to its set back from the front and rear parapets and position of the property at No 111, it would be visible from the roof terraces and upper storey windows of the surrounding buildings. From these private views, the proposal would appear as a discordant feature in the terrace’s roofscape.

As a consequence, the contribution that the host property and the terrace make to the character and appearance of the conservation area would be significantly eroded by the new roof extension. It follows therefore that the proposal would neither preserve or enhance the character or appearance of the conservation area.

Due to the limited views of the proposal from the [address] streetscene the extent of the development’s harm to the Kensington Conservation Area as a designated heritage asset would be less than substantial. In such circumstances, paragraph 202 of the Framework indicates that this harm should be weighed against the public benefits of the proposal. However, whilst I note that the proposal would provide increased accommodation for the appellant and his family this is a private as opposed to a public benefit. Accordingly, I find that there are no public benefits to outweigh the harm that would be caused to the conservation area, a matter to which I give great weight in line with the Framework.

Given the above, the proposal would not preserve or enhance the character or appearance of the Kensington Conservation Area, in conflict with the Royal Borough of Kensington and Chelsea Local Plan, adopted September 2019, specifically Policies CL1 and CL2 which seek to ensure development responds to the local context and character of the site. It would further conflict with Policy CL3 which seeks to resist demolition in conservation areas that would result in harm to a heritage asset; Policy CL8 which seeks to ensure roof alterations are architecturally sympathetic to the age and character of the building and group of buildings; and Policy CL11 which seeks to ensure development protects or enhances views within conservation areas. There would also be conflict with the Framework’s objective to conserve and enhance the historic environment.

The appellant has referred to a recent decision, application reference PP/19/06891, undertaken by a Planning Applications Committee where the loss of a butterfly roof was considered appropriate. The full details of the development have not been provided, however it appears from the report submitted that this proposal was considered acceptable because of its context, which is not the case with the proposal before me. The granting of planning permission in this case does not provide justification for harmful development.

The proposed development would not accord with the development plan when considered as a whole. Based on the above, and having regard to all matters raised, I recommend that the appeal should be dismissed.

I have considered all the submitted evidence and the Appeal Planning Officer’s report and on that basis I agree with the recommendation that the appeal should be dismissed.