Appeal 3336967

The appeal is dismissed.

The amendments of the National Planning Policy Framework (the Framework) were published in December 2023. These amendments do not alter the basis upon which this appeal has been assessed.

It is considered that the main issue is the effect of the proposed development on the character and appearance of the host property and the surrounding area.

The appeal property is included within the Gunnersbury Park Conservation Area where there is a statutory duty to preserve or enhance the character or appearance of the area. This duty is echoed in Policy CC4 of the Hounslow Local Plan (LP). The Conservation Area has 2 distinct parts which contribute to its heritage significance. There is the extensive open area associated with Gunnersbury Park and a residential area comprising a 1920s garden suburb where there are 2-storey semi-detached and terraced dwellings fronting roads with rear access for parking. Within the garden suburb there is a consistency in the character and appearance of this area associated with the design, roofscape and siting of the dwellings and the choice of external materials. The property is situated within this part of the Conservation Area.

The property is a 2-storey dwelling which forms the end house of a terrace of 6 dwellings. The end dwellings of the terrace possess hipped roofs but 49 The Ridgeway, adjacent to the property, possesses a more complex roof form created by a side gable dormer extension which partially retains the outline of the original hipped roof. This dormer appears an awkward addition to the side roofslope and this awkwardness also includes the juxtaposition between the side and rear dormer extensions which are visible from [address].

The proposed development includes a hipped to gable roof extension together with the erection of a rear dormer which would have its side elevation sited directly above the flank wall of the property. When viewed from the access roads, rear dormers are a feature within the surrounding area but they are generally of a modest size and design, including being set back from the side elevations of the dwellings.

Guidance contained in the Council’s Residential Extensions Guidelines Supplementary Planning Document (REG) includes reference to dormers being set back from the edge of roofs and their scale not appearing like a large box. By reason of the siting and scale of the proposed rear dormer, together with the alteration to the roof form, it would be a bulky addition to the property which would not be of a high quality of design. The increase in bulk would be noticeable through the gap between the property and No. 49 because of the siting of the proposed dormer’s side elevation and also from [address] which provides access to the rear of the terrace of dwellings. Unacceptable harm would be caused to the character and appearance of the host property by reason of the siting and scale of the appeal scheme.

The siting and design of the proposed dormer would not restore the symmetry between the property and No. 49 as claimed by the appellant. Conversely, the Council’s claim that the terrace would be unbalanced as a consequence of the proposed alterations to the property’s roof does have some merit. However, because of the length of the terrace, it would not alone amount to a reason for this appeal failing but it does add, albeit in a limited way, to the unacceptable harm which has been identified. There would be a diminution in the positive contribution made by the terrace and host property to the consistent and coherent character and appearance of this part of the Conservation Area.

Where a development proposal will lead to less than substantial harm to the significance of a designated heritage asset, the Framework identifies that this harm should be weighed against the public benefits of the proposal. In the case of the proposed development, the appellant has not identified any public benefits with any benefit only being related to the increase in the property’s habitable accommodation.

Reference is made by the appellant to other schemes in the area, including at [address] which was visited during the site visit. However, the detailed planning circumstances of these other schemes have not been provided. In any event, the application referenced by the appellant for No. 77 was for a Certificate of Lawful Development rather than a planning application which requires to be assessed against the relevant development plan policies. For these reasons, limited weight is given to these other schemes and the proposed development has been assessed based upon its own circumstances.

For the reasons given, it is concluded that the proposed development would cause unacceptable harm to the character and appearance of the host property and the surrounding area and, as such, it would conflict with [name] SC7, CC1, CC2 and CC4 and the guidance contained in the REG. Amongst other matters and in addition to heritage considerations, there is a general reference in these policies to refusing poor quality design and requiring residential extensions to complement the existing building and to maintain the character of the general streetscene.

Accordingly, and for the reasons given, it is concluded that this appeal should be dismissed.