Appeal 3292558

The appeal is dismissed.

I have taken the description of the development in my banner above from the application form. However, I note that the Council’s decision and the appeal form also refer to a hip to gable extension and to two front roof windows. I have therefore considered the impact of all that development, which I observed on my visit is already in place.

The main issue is the effect of the development on the character and appearance of the host property and the area, including whether it preserves or enhances the character or appearance of the St Dunstan’s Conservation Area.

Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 requires, in respect of development affecting conservation areas, that special attention shall be paid to the desirability of preserving or enhancing the character or appearance of the area. Policy CC4 of the Hounslow Local Plan 2015 to 2030 (2015) (‘HLP’) broadly reflects that approach in its requirement for development to conserve and take opportunities to enhance the character of conservation areas, and to respect the grain, scale, form, proportions and materials of the surrounding area.

The National Planning Policy Framework 2021 (‘Framework’) sets out at paragraph 199 that when considering the impact of a proposed development on the significance of a designated heritage asset, such as a conservation area, great weight should be given to the asset’s conservation.

The appeal site lies within the St Dunstan’s Conservation Area (‘SDCA’). This is described in the St Dunstan’s Conservation Area Appraisal 2018 as the focal point of [name], which still has the form and grain of the rural settlement it once was, and which retains some key buildings and open spaces.

The host property sits amongst buildings of varied style and proportions, in both commercial and residential use, and some of which are of an unsympathetic design. However, together with the two other properties in this short terrace, the host forms a small, cohesive, late nineteenth century group, which is similar in style to the adjacent terrace at Nos 19 to 25. Notwithstanding some alterations, other than No 13, these terraces broadly retain their original and simple form, with largely unaltered roofs terminating with a hip. They therefore make a positive contribution to the character and appearance of the area.

As the other end of this building has a hipped roof, the hip to gable extension here has significantly unbalanced this terrace. Additionally, given that the rear dormer extends roughly from the host’s eaves to its ridgeline, and covers almost all of the roofslope, including the hip to gable extension, it entirely dominates the rear roofscape.

As a result, the property’s original roof form, particularly to the rear, has been almost entirely subsumed. The harm that causes is visible in the streetscene through the gap between 11 and [site address] where the host has an awkward and rectilinear form, and can also be glimpsed from other vantage points looking across commercial land from [address], as well as between buildings broadly to the south.

The Council’s Residential Extension Guidelines Supplementary Planning Document 2017 states that rear dormer windows in conservation areas should be modestly sized, should not dominate the roof, should generally be less than half the width of the original roof, and should be set down 1 metre from the ridge and up 1 metre from the eaves. This development clearly conflicts with that approach.

[name] observed a nearby roof extension within the SDCA at [address], unlike here it is set in from the side wall and it is on a semi-detached property of a different style and era.

For the above reasons, the development has harmed the character and appearance of the host property and the area. It therefore conflicts with [name] CC1, CC2 and SC7 which, amongst other things and in broad terms, require development to respond to an area’s character, with extensions which complement, and are subordinate to, the original building and which harmonise with adjoining properties and the streetscene. Given the harm that has been caused to the SDCA, it also conflicts with HLP Policy CC4.

Summing up, the scheme has harmed the form and appearance of the host property and this characteristic terrace. In so doing it fails to preserve or enhance the character or appearance of the SDCA. In accordance with the Framework, this is a matter to which I attribute great weight. However, as the harm is ‘less than substantial’, in accordance with the Framework, I am required to weigh it against the public benefits of the proposal.

In this case, the harm that the scheme causes to the SDCA is not outweighed by the very modest public benefit of providing additional accommodation. Consequently, as well as conflicting with the development plan, the scheme conflicts with the Framework.

For those reasons, and having regard to all other matters raised, including representations by interested parties, the appeal is dismissed.