Appeal 3324511

The appeal is dismissed.

I have taken the description of development from the Council’s decision notice since it describes the proposal in greater detail than the description contained in the planning application form.

The Council has clarified that the Urban Design Guide Supplementary Planning Document 2023 (SPD) supersedes the General Design Principles Supplementary Planning Document (SPG) and the Residential Design Guidance SPG, referred to by both parties in evidence.

The main issue is the effect of the proposals on the character and appearance of the host dwelling and whether they would preserve or enhance the character or appearance of the Chislehurst Conservation Area (CA).

The appeal site lies within the [name]. The statutory duty under Section 72 of the Planning (Listed Buildings and Conservation Areas) Act 1990 requires me to pay special attention to the desirability of preserving or enhancing the character or appearance of the CA.

The CA covers a large area of Chislehurst and is diverse in the building types, pattern of development and land uses it includes. It incorporates the commons around which Chislehurst developed and contains clusters of development which show the evolution of Chislehurst to the present day. Remnants of woodland and common land give the area an open, semi-rural character. Whilst there are some pockets of dense, largely 19th Century development, particularly around the shopping parades, the CA also has large areas of low density, suburban style development.

Reflecting the wide range of character areas it covers, the Chislehurst Conservation Area Supplementary Planning Guidance (SPG) (adopted 1999 and updated 2001) identifies character sub-units. The appeal site is located within sub-unit 11, [address] and [name]. This area is characterised by post-war housing set in spacious plots amongst mature trees with occasional examples of earlier buildings.

I consider the significance of the CA to be derived from the pattern of development around the commons and other open or wooded areas, along with the wide variety of character areas. In terms of the residential area in which the appeal site is located, the significance here is derived from the spacious plots and largely 2 storey housing of similar appearance, with hipped, tiled roofs, typically brick or rendered elevations.

The proposal includes a loft conversion with front and rear dormer, along with an increase in height of the roof ridge. To the front, there would be a part ground/first floor extension to enlarge the porch, garage and first floor landing. There would also be an extension to the rear at ground and first floor to enlarge the living and bedroom accommodation.

There is little evidence to suggest that second floor front dormers are a characteristic feature of the area, and the introduction of such a dormer to the appeal property would appear as an incongruous feature in this part of the CA. Policy 6 of the Bromley Local Plan 2019 states that dormers should be sited away from prominent roof pitches, unless dormers are a feature of the area.

Whilst there are some examples of rear roof dormers in the area, the dormer shown in the proposal would be overly dominant in relation to the host building and would be visible from [address] as well as from rear gardens of surrounding houses. The width of the dormer would be excessive and would appear out of proportion in relation to the rear elevation as a whole.

The front and rear dormers, when taken together, along with the increase in ridge height would have the effect of changing the proportions of the house, making the roof appear rather top heavy and overly dominant. I acknowledge that the proposed front and rear dormers would be set below the ridgeline, in accordance with the advice contained in paragraph 4.30 of the [name]. However, that same paragraph also acknowledges that in some cases dormers will be inappropriate, particularly on prominent front or side rooflines, and that where an opportunity is identified, the scale of the dormer should respond to traditional styles, usually requiring some restraint of the urge to maximise internal spaces to avoid adversely impacting upon the appearance of the building and CA. Similarly, the guidance contained in DG5 of the [name] 2023 seeks to ensure that, amongst other things, roof forms are proportionate in size, minimise the visual impact on the street and positively respond to the character of the area.

For the reasons set out above, and given the scale of the proposals, I find that there would be less than substantial harm caused to the significance of the CA.

The extensions at ground and first floor to both front and rear would respect and reflect the form and appearance of other houses in this part of the CA and would not overly dominate the front or rear elevations. I do not consider that the loss of the first floor dormer or cat-slide roof to the porch would be harmful to the CA, and the introduction of the pitched roof above the entrance and garage would provide some interest and articulation in the front elevation. For clarity, this would not contribute to the harm already identified and it holds neutral weight in my determination of the appeal.

I conclude that the proposal, specifically the roof extension, would be harmful to the character and appearance of the host dwelling and would fail to preserve the character and appearance of the Chislehurst Conservation Area. The proposal, therefore, would conflict with Policies 6, 37 and 41 of the Bromley Local Plan 2019. These policies, amongst other things, require development to respect or complement the scale, proportion and form of the host building and of the local character and context.

Whilst not referred to in the reason for refusal, London Plan 2021 Policies D1, D3 and D4 have been referred to in the evidence. The proposal would be contrary to the aims of Policy D3 of the London Plan 2021 which relates to optimising site capacity through a design led approach. Amongst other things, the Policy sets out that development proposals should enhance local context by delivering buildings and spaces that positively respond to local distinctiveness. I note the parties also refer to Policies D1 and D4 of the London Plan in their evidence, but I do not consider either determinative as they do not directly address the issues in dispute.

The alterations would provide some improvements to the internal layout and accommodation available for current and future occupiers of the property, including an additional bedroom and enlarged living spaces. I consider these benefits to be largely private. As such, the public benefits are not sufficient to outweigh the identified less than substantial harm to the significance of the designated heritage asset. Therefore, the proposal would not accord with the policies of the National Planning Policy Framework which seek to conserve and enhance the historic environment.

I have found that the appeal proposal would not preserve or enhance the character or appearance of the Chislehurst Conservation Area. As such it is contrary to the development plan read as a whole. The material considerations in this case do not indicate that the decision should be taken otherwise than in accordance with the development plan. The appeal is therefore dismissed.