Appeal 6003665

The appeal is dismissed.

The site visit was undertaken by a representative of the Inspector whose recommendation is set out below and to which the Inspector has had regard before deciding the appeal.

The main issue is the effect of the proposed development on the character and appearance of the host building, a Building of [name] (BTM), and the group it forms part of.

The appeal property is a large detached two storey residential building that has been divided into flats. Attic accommodation is provided in the gable roof. The appeal relates to the first floor flat. Planning permission was granted in July 2025 for a rear extension of the ground floor flat (under separate ownership). The appeal proposal for a first floor rear extension would be built on top of the ground floor extension.

The appeal property and the neighbouring buildings (Nos. 328-342 [site address] ) all have a similar appearance and have been designated locally as BTM. The buildings form an attractive group, retaining many of their original features including distinctive ground floor arched entrances at the front and sash windows. The group of buildings are in a deliberate stepped arrangement which is discernible from the front and rear of the properties. Overall, the appeal property and the properties as a group are cohesive, well proportioned and aesthetically pleasing.

At the rear, the properties show more variation, with a number of the buildings in the group having been extended at ground floor level. However, the appearance of the first floors and roof remain largely consistent.

The Council note that the [name] and External Alterations Supplementary Planning Document ([name]) states that two storey side and rear extensions should not be greater than half the width of the original building, to ensure the extension does not over-dominate the building’s original scale and character. The first floor extension is only approximately half the width of the building and when considered alone the width and depth would be proportionate to the host building, resulting in only a fairly modest increase in floorspace. However, the proposals to extend the ground floor are more significant and span the entire width of the building. When viewed together, the extensions would overly dominate the rear of the building.

I can see that the rear extension has used a stepped design to respond to the form of the historic building and the pitch and style of roof has been designed in symmetry with the existing roof. Despite this, the proposed roof arrangement, incorporating a hipped roof to adjoin the existing roof, entirely changes the appearance and form of the rear of the building which would harm the architectural significance of the BTM and the cohesiveness of the group. The stepped arrangement of the group of BTM would also be noticeably disrupted by the proposal. Whilst it is noted that materials have been chosen to match the style of the dwelling, this would not address the more fundamental issues of design and bulk.

I have had regard to paragraph 216 of the National Planning Policy Framework (the Framework) which explains that the effect of an application on the significance of a Non-Designated Heritage Asset should be taken into account in determining the application. In weighing applications that directly or indirectly affect non-designated heritage assets, a balanced judgement will be required having regard to the scale of any harm or loss and the significance of the heritage asset.

Recognising the position of the proposed rear extension to the street, and its resulting reduced prominence the harm conveyed to the BTM would be moderate only. However, this harm would not be outweighed by any identified benefits, other than some private benefits to the appellant.

I have found that the rear extension would be out of keeping with the design of the building and as a result would unacceptably affect the character and appearance of the building and the group of buildings it forms part of. Furthermore, the proposal would result in moderate harm to a BTM and would not preserve its special interest or significance. Accordingly, the proposal would not accord with Policy 28 of the Richmond Upon Thames Local Plan ‘The best of our borough’ (2024 – 2039) (October 2025) (the Local Plan) which seeks, amongst other things, to ensure development seeks to maintain and enhance high architectural and urban design quality. It also does not accord with Policy 30 of the Local Plan which seeks to ensure development preserves, and where possible enhances, the significance, character and setting of non-designated heritage assets, including Buildings of [name]. It is also contrary to the [name] which states that extensions should not dominate the existing house and should harmonise with the original appearance.

The appellant has provided examples of a number of first floor rear extensions that have been granted planning permission along [site address] . I am consonant that many first floor extensions exist in the locality, however none of the examples are from within this specific group of BTM. I also do not have details of the proposals or the planning circumstances that led to their approval. They are therefore not comparable to the appeal proposal and do not weigh in favour of allowing the appeal.

I appreciate that the appellant sought pre-application advice from the Council and sought to design a scheme that was in accordance with policy and guidance and the principle of development. I also note that changes were made to the proposal to remove a side window to ensure no loss of privacy would occur to the occupiers of a neighbouring property. However, these are not factors which weigh in favour of allowing the appeal and do not diminish the harm that I have found on the main issue.

The proposal would conflict with the development plan as a whole and there are no other considerations, including the provisions of the Framework, which outweigh this finding. For the reasons given above and having had regard to all other matters raised, I recommend that the appeal should be dismissed.

I have considered all the submitted evidence and my representative’s report and on that basis the appeal is dismissed.