Appeal 3328448

The appeal is dismissed.

The main issue in this case is the effect of the proposal on the character and appearance of the host dwelling and the setting of the neighbouring listed building Nos [address] and, linked to that, whether the proposal would preserve or enhance the character or appearance of the Belgravia Conservation Area.

[site address] is a modern three-storey townhouse located at the edge of [address] close to its junction with [address], from where it can be seen. The site is within the Belgravia Conservation Area which is characterised by the formal arrangement and hierarchy of planned terraced dwellings and open spaces.

The building is unlisted but lies immediately adjacent to the Grade ll listed building [address] which comprises a row of houses built in the early C19. The row has a regular pattern of fenestration and architectural detailing such that the dwellings create a harmonious composition. The properties have a consistent pattern of dual pitched mansard roofs with dormer windows at the lower level.

No 83A was designed by a renowned architect and is of a simple, uncluttered flat roofed form. The materials, fenestration and the proportions of the building reflect those of the terrace and its modest scale and appearance respects the hierarchical characteristics of the surrounding area. The building is set back from the front elevation of the terrace and is considerably lower in height such that the form and detailing of the listed building is apparent from the side. No 83A replaced an earlier building on site and sits adjacent to a single storey commercial building, thought to be a former service building, which is flat roofed. The appellant’s Heritage Impact Assessment notes that the building makes a positive contribution to the area.

The proposal seeks to add a slate covered mansard roof extension to provide an additional en-suite bedroom and an external rear terrace above the second floor. Two lead clad dormer windows would be provided to the front and one to the side.

The proposal would increase the height of the building such that more of the side elevation of the terrace, specifically the end property No 84, would be obscured. I note the extension has been carefully considered such that the fabric of the listed building and architectural features including the blind windows and the cornice would not be physically affected. However, the blind windows, designed to relieve an otherwise featureless wall, denote the ‘bookend’ nature of No 84. This feature, and the cornice which provides architectural definition to the building, is repeated on the gable walls of the buildings flanking the entrance to [address] off [address]. Obscuring these features would diminish the legibility of No 84 as the end property of the listed building.

Other than in limited views, only the steeply pitched lower part of the mansard roof of the listed building is readily visible from the public realm. As such the roof is not a prominent feature of the building and it appears subordinate in terms of its proportions to front elevation. Where the profile of the roof can be seen, from [address] and the end part of [address], the upper part is hipped back to a central ridge, as such reducing its apparent bulk. In contrast, the proposed mansard would have a tall, box-like profile that would be unsympathetic to the traditional characteristics of the building and the roof of the adjoining terrace. Furthermore, it would be disproportionate to the building in terms of its height and scale and as such the resulting building would appear top heavy and discordant. On that basis, even though the hierarchy of buildings would be retained, the proposal would diminish the positive contribution the building makes to the area.

The Council’s Conservation Area Audit for Belgravia 2013, a draft document, notes there are numerous examples of roof alterations and extensions throughout the Conservation Area which are considered negative features. A mansard extension opposite the site at No 81 is specifically noted as being poorly detailed. Accordingly, the roof extension in that case, which is similar in terms of its form and scale, is not a good example of development to follow.

For the reasons set out above, the proposal would detract from the architectural quality of the host building, the immediate setting of the listed building and would neither preserve nor enhance the character or appearance of the Belgravia Conservation Area. Consequently, the proposal would be contrary to Policies 38,39 and 40 of the City Plan which seek amongst other things to ensure all development contributes positively to Westminster’s townscape having regard to the character and appearance of the existing area, adjacent buildings and heritage assets; ensure heritage assets and their settings are conserved and enhanced in a manner appropriate to their significance and is of an appropriate design sympathetic to the architectural character of the existing building.

On that basis the proposal would not satisfy the weighty statutory requirements of s.66 (1) and s.72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (the Act) which require that in considering whether to grant planning permission for development which affects a listed building or its setting, special regard should be had to the desirability of preserving the building or its setting or any features of special architectural or historic interest which it possesses and, in respect of buildings within a Conservation Area, to the desirability of preserving or enhancing the character and appearance of that area.

The approach in the National Planning Policy Framework is that where a proposal would lead to less than substantial harm to the significance of a designated heritage asset, as in this case, that harm should be weighed against the public benefits of the proposal including, where appropriate, securing its optimum viable use.

The proposal would provide additional living accommodation in the form of a fourth bedroom with en-suite bathroom and external terrace. I understand from data provided by the appellant1 that there are fewer four bedrooms homes in Westminster than elsewhere in London and the rest of England, although there are also fewer three bedroomed properties. Policy 10 of the Westminster City Plan (2021) seeks to increase the number of new family sized homes in the area. However, I am unconvinced on the basis of the evidence before me that the existing three-bedroomed dwelling is incapable of functioning as a family home. Accordingly, this limits the weight I can give to the matter as a public benefit. As such, the public benefits of the proposal do not outweigh the harm I have identified to the heritage assets, which carries great weight.

The proposal would provide enhanced living accommodation for the owner of the building. However, this is private benefit and can carry only limited weight in my considerations.

I acknowledge the concerns of neighbouring occupiers regarding the potential for a loss of privacy as a result of the proposed terrace. I noted at my site visit the number of windows facing the appeal site at the rear of properties on [address]. [name] been minded to allow the appeal the matter could have been dealt with by a condition requiring the construction of permanent screens to the sides of the terrace to prevent direct overlooking such that occupier’s living conditions would not have been significantly affected.

There are no circumstances that indicate that planning permission should be granted other than in accordance with the development plan. On that basis, taking into account all I have seen and read, the appeal is dismissed.