Appeal 3290619

The appeal is dismissed.

An application for costs was made by [name] against the London Borough of Hounslow. This application is the subject of a separate decision.

The main issue is the effect of the proposed development upon the character and appearance of the building and the locality, with particular regard to the Grove Park Conservation Area (CA).

Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990, in respect of development affecting conservation areas, states that special attention shall be paid to the desirability of preserving or enhancing the character and/or appearance of the area.

The CA’s significance is highlighted in the Grove Park CA Appraisal 2021, where relevant components of the significance in relation to the appeal site relate to the development of the first large speculative Victorian housing development in Chiswick. The area contains formally laid out ‘upper class’ mansions with further late Victorian and early twentieth century development of high architectural merit. The majority of dwellings around and including the appeal site are noted in the [name] as being with the [name] area and are positive contributors to the significance of the www.planningportal.gov.uk/planninginspectorate 1 Appeal Decision: APP/F5540/D/22/3290619 CA. Threats to the significance of the CA as detailed in the appraisal include the infilling of side gardens which reduce the prevailing character of spaciousness and roof extensions that fill gaps and reduce skylines, amongst others.

The dwellings along this character area contain late Victorian and Edwardian dwellings, with larger houses located along [address] situated amongst well vegetated surrounds with setbacks to boundaries. The scale, massing, spacing and design are some of the elements which emphasise status and affluence. [address], is a later early-mid twentieth century development of semi-detached dwellings which although have a lower status and scale than [address], have a regimented layout with setbacks and an emphasis of spaces in and around dwellings. The use of traditional materials such as timber, brick and slate along with the similar designs reinforce a uniformity and authenticity within the character area which creates a formal picturesque townscape along with vegetated front gardens and street trees give a spacious, leafy and distinctive character.

The appeal site is located on the corner of [address] and [address] and displays a number of positive qualities of significance to the CA, being a high quality two storey detached building which is noted as a positive element which contributes to the character and appearance of the area. The building itself has more of an Edwardian inspired design than the arts and crafts inspired buildings surrounding, and contains a main gable fronting [address] which has accommodation within its roof space. The building has had a later two storey side extension that is set back from the main facade.

In undertaking extensions to existing buildings, the London Borough of Hounslow Local Plan (LP) Policies CC1 and CC2 are design led policies which seek to achieve high quality design for new development which reflects the existing character and context of the locality. LP Policy CC4 relates to heritage assets and seeks that alterations and extensions demonstrate that regard is had to the significance of heritage assets and that development is in keeping with the building and wider area. LP Policy SC7 is specific to residential extensions and seeks that extensions do not harm existing character and appearance and also seeks that the Residential Extensions Guidelines Supplementary Planning Document 2017 (SPD) is taken into account in planning determinations. The SPD contains further specific guidance in relation to design principles and detailed design considerations that for side extensions places an emphasis on subservience and responding to the existing site and context of the locality.

The proposed extension would convert the garage to part of the living accommodation and at first floor level and would extend the width of the extension over the existing garage and towards the boundary with Devonshire gardens, and an increased depth of the existing two storey extension under a new enlarged hipped roof. Currently the width of the two storey element appears to be in line with the regimented setback of dwellings along [address] where there is an emphasis on spacious setbacks, particularly from the front boundary which would be the side boundary of the appeal site. The proposed first floor would in this instance www.planningportal.gov.uk/planninginspectorate 2 Appeal Decision: APP/F5540/D/22/3290619 present a forward protrusion towards the [address] boundary that would erode the important space in and around dwellings which is part of the significance of this CA and is specifically noted in the CA appraisal as a threat to its significance. The combined increased width and depth of the proposal would be excessive in this particular context and would therefore not result in a subservient addition to the existing building.

I appreciate the explanations in the applicant’s Statement of Case (SoC) with regards to the evolution of the proposal and the adaptation of amendments to attempt to alleviate the Council’s concerns regarding the scheme. I agree with the applicant that the SPD is not specifically relevant to the scheme, however the SPD is guidance and may not reflect all possible circumstances. In relation to corner plots, the SPD suggests a 1 metre setback, however also suggests that design depends on its context and surrounding environment. In this particular case there is an emphasis on spaciousness, subservience of extensions and visual gaps in and around dwellings as per the CA appraisal and [name] CC1, CC2, CC4 and SC7. In this particular case the forward protrusion of the first floor towards the boundary, although reduced from previous schemes, combined with the increased depth would still create an awkward and disproportionate relationship when experienced in the street scene along [address] and turning the corner along [address].

Taken as a whole, the dominance and lack of proportionality of the proposed extension would cause unacceptable detriment towards the architectural authenticity and integrity of the existing building and cause harm towards the character and appearance of the CA. Consequently, the proposal would be contrary to the [name] CC1, CC2, CC4 and SC7 which is accompanied by the SPD, all of which have been described previously. I therefore disagree with the applicant’s SoC that no harm would be caused.

Although serious, the harm to the heritage asset in this case would be ‘less than substantial,’ within the meaning of the term in paragraph 202 of the National Planning Policy Framework (the Framework). Paragraph 200 of the Framework states that any harm to, or loss of, the significance of a designated heritage asset requires clear and convincing justification. Paragraph 202 of the Framework requires that, where a proposal would lead to less than substantial harm, the harm should be weighed against the public benefits of the proposal.

The applicant has not outlined any public benefits of the scheme, however to me, the public benefits of the scheme would deliver larger residential accommodation for the existing dwelling, as well as result in short term employment opportunities in the construction of the extension. However, these benefits may also be present in a more appropriately designed scheme.

I therefore find that the public benefits would not outweigh the harm to the CA. The scheme therefore conflicts with the Framework, which directs, at paragraph 199, ‘that great weight should be given to the asset’s conservation ... irrespective of whether any potential harm amounts to substantial harm, total loss or less than substantial harm to their significance’. www.planningportal.gov.uk/planninginspectorate 3 Appeal Decision: APP/F5540/D/22/3290619

In conclusion on this matter, I consider the proposed development would cause less than substantial harm to the significance of the CA. It has not been shown that public benefits would outweigh this harm and so the proposal would conflict with the development plan.

For the reasons given above the appeal is dismissed.