Appeal 3327881

The appeal is dismissed.

The main issue if the effect on the character and appearance of the appeal dwelling and that of the Blackheath Park Conservation Area (the CA).

The appeal dwelling is a 3 storey detached house with a hipped roof, sitting on a generous plot. It forms a pair of similarly designed, classically symmetrical dwellings that are located within the private [name], which constitutes a substantial part of the CA. The significance of the CA stems from the development of the estate from the late 18th Century to the present, and the resulting architectural quality and variety of its buildings, the majority of which are residential.

The Conservation Area is a heritage asset to which I have a statutory duty under section 72 of the Planning (Listed Buildings and Conservation Areas) Act 1990. I must pay special attention to the desirability of preserving or enhancing the character or appearance of a Conservation Area.

The proposed rear ground floor element of the proposal involves the demolition of two existing conservatories and the raising of the sill of a centrally positioned arched first floor window. It would be approximately 4 metres deep and 3.2 metres in height, with a flat roof, and would span across most of the rear elevation of the appeal dwelling, with only a slight set in from the boundary with its adjacent detached pair.

The first floor element of the proposal would be approximately 3 metres deep and 4.25 metres in width. It would align with the flank wall of the ground floor element and the flank wall of the appeal dwelling, extending in width to a position close to the existing arched window. The roof of this element of the proposal would be hipped into the existing rear roof and would align with and continue the existing side roof slope. It would appear that the full height to the ridge of the hipped roof of the proposed extension would be approximately 8 metres.

The extended flank wall of the proposal and the continuation of the side roof slope would be visible from the street, and would interrupt the profile of the appeal dwelling, a profile it shares with its neighbouring detached pair. From the rear the first floor element of the proposal would read as a substantial and prominent addition to the appeal dwelling, which would be apparent in views from the rear of surrounding properties within the CA. In these views the scale of this part of the proposal, along with its proposed continuation of the existing roof and flank wall would appear as dominating and to interrupt the profile of the appeal dwelling, detracting from its architectural symmetry.

The proposed pair of first floor windows in the existing blank white painted flank wall would be small and square with a single pane of opaque glazing. The design of these proposed windows would not reference the scale, proportions, and traditional detail of the appeal dwellings existing windows. They would, therefore, appear as discordant and discordant insertions, which would interrupt the composition of the appeal dwelling symmetry and its existing architectural expression.

Whilst, from the rear, the ground floor element of the proposal would have a limited effect on the appearance of the appeal dwelling, the first floor element of the proposal would result in the proposal as a whole appearing to be an unduly prominent, overbearing, and incongruous addition to the appeal dwelling. This would be evident in wider and immediate views from both the front and rear, where it would not appear to be a subordinate addition. For these reasons, the proposal would fail to accord with the Royal Borough of [name], Basements and Conversions Guidance Supplementary Planning Document (2018).

Along with the proposed first floor opaque windows in the flank of the appeal dwelling, the proposed part 1/part 2 storey extension would detract from the cohesive and mirrored architectural appearance and symmetry of the appeal dwelling with its detached pair. As this would be evident in public and private views of the appeal dwelling and the pair of houses of which the appeal dwelling forms part, this would not reflect the architectural quality of properties in the area, which constitutes a substantial element of the significance of the CA.

Whist the proposal would result in a larger house with more living space for its occupants, these are primarily private rather than public benefits and planning decisions are generally made in the public interest. Public benefits in this instance would, therefore, be limited.

For the reasons given above, the proposal would result in significant harm to the character and appearance of the appeal dwelling and would fail to preserve or enhance the character or appearance of the CA. This would conflict with Policies DH1, DH3, DH(a) and DH(h) of the Royal Greenwich Local Plan: [name] with [name] (2014), Policies D3 and HC1 of the London Plan (2021) and Sections 12 and 16 of the National Planning Policy Framework (2023) (the Framework). These collectively seek to ensure that development is of high quality design, a key aspect of sustainable development, and has due regard to the importance of preserving or enhancing heritage assets.

[name] find the harm to the CA is less than substantial, in accordance with the Framework, great weight should be given to its conservation as a heritage asset. In addition, I have given substantial weight to the effects on the character and appearance of the appeal dwelling. As the public benefits of the development do not outweigh the harm I have identified, the development conflicts with the development plan as a whole and with the heritage aims of the Framework.

For the reasons given, I conclude that the appeal should be dismissed.