Appeal 3289025

The appeal is dismissed.

During the determination of the planning application, the proposed extension’s design was revised which included the deletion of an air conditioning unit. The appeal has been considered on the basis of the amended plans.

The main issue is whether the proposal would preserve or enhance the character or appearance of the Pimlico Conservation Area.

The appeal site comprises a four-storey terraced dwelling with a mansard type roof at the top storey and additionally a basement. To the rear, there is a closet wing extension just over two storeys, with additional basement below, on one side, which is flat roofed. It terminates at a point about a third of way up on the building’s penultimate storey. On the frontage, the terraced house has a stucco finished classical frontage, including a rusticated pattern at the ground floor and a mansard type top floor. The appeal site and terrace are located within the Pimlico Conservation Area.

The Pimlico Conservation Area occupies a large area of mainly similar housing. The Westminster Pimlico Conservation Area Audit details a how a speculative developer, [name] began to build here in the mid-1830s, with subsequent developers continuing a distinctive classical building design style. Housing comprises stucco-fronted terraces built along straight streets and around three squares. Street design is strongly characterised by the matching pattern and appearance of terraced dwellings. To the rear, elevations are subservient to the front facades but nevertheless, they remain balanced and symmetrical with regular spaced and matching fenestration. There are rear projecting extensions/projections of varying heights, widths, and depths, but nevertheless, they remain typically square shaped and flat roofed, and not overly dominant. As such, they do not overwhelm the uniformity of the original design.

It is these architectural and historic qualities that are of importance and contribute to its significance and its special interest. The appeal property contributes positively to the character and appearance of the Conservation Area by reason of its classical built form and architecture. In relation to the frontage, the rear has a more subordinate and simpler architecture. Despite the extension, it has retained original features in keeping with the classical design qualities of the housing within the Conservation Area.

The City of Westminster Development and Demolition in Conservation Areas Supplementary Planning Guidance (SPG) states the design of rear extensions and alterations must respect the architectural character of the existing building, the terrace of which it is part (if it is within a terrace) and the Conservation Area, taken as a whole. Extensions should respect the scale and proportions of the existing building and must be architecturally subordinate to the main building.

The appeal property is one of a few along this terrace that do not have an existing full height extension. The proposed extension would be less deep than the existing extension below it and would step back from the existing extension below it. However, the proposed extension would have an unusual shape with a chamfered rear face, and it would rise slightly above the parapet on the mansard roof above. As such, it would have a jarring and incongruous design impact on the rear of the appeal dwelling and surrounding terrace.

There is a bowed shaped extension, with parapet above the roof eaves, at [address] but this is the exception to the general pattern of square and flat roofed type extensions to the rear of [address] and [address], a street that backs onto the appeal property terrace. In any case, the high-rise parapet serves to demonstrate the harm that would arise with the current proposal. As such, the proposed extension would adversely stand out and would be detrimental to the character and appearance of the Conservation Area.

Due to its rearward location, the extension would not be visible from public vantage points. However, Conservation Areas are protected for their inherent architectural and historic significance irrespective of whether or not public views of the proposal can be gained. Furthermore, the extension would be particularly out of keeping due to its shape and height. The extension would be constructed with brickwork of a painted finish to match the extension below which is to painted white. The window sash window would also be designed to match that below. Details of such materials and finishes, and type of windows could be conditioned to ensure that they would be in keeping with the dwelling and Conservation Area.

The chamfered extension design would aim to minimise the loss of light and outlook to a neighbouring property, but this would not address the visual harm identified. The extension would result in less than substantial harm in accordance with the National Planning Policy Framework (the Framework) for all the reasons indicated. It is necessary that this identified harm is weighed against the public benefits of the proposal.

The upgrade of the existing dwelling to provide a study would largely be a private benefit but there would be a small public benefit through enhancing a dwelling as part of the Council’s housing stock. However, considerable importance and weight are attached to the desirability of preserving the character and appearance of the Conservation Area. Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 requires that special attention shall be paid to the desirability of preserving or enhancing the character or appearance of the Conservation Area. Therefore, the harm to the significance of the Conservation Area would outweigh the scheme’s benefits.

The extension would not preserve the character and appearance of the Pimlico Conservation Area for all these reasons. Accordingly, the proposal would conflict with Policies 38, 39 and 40 of the Westminster City Plan 2019-2040, which collectively and amongst other matters, require development to be of exemplary high standards of design, positively contribute to its townscape and streetscape, conserve or enhance the character and appearance of the Conservation Area and be sensitively designed, having regard to the prevailing scale, heights, character, architectural quality and degree of uniformity in the surrounding townscape.

For the reasons given above and having regard to all other matters raised, I conclude that the appeal should be dismissed.