Appeal 3307476

The appeal is dismissed.

Although not complete, works were being undertaken on the property during my site visit. I am therefore dealing with the appeal, in part, retrospectively.

The main issues are the effects of the proposed development on: • The character and appearance of the host property, a non-designated heritage asset; and • The living conditions of the occupiers of Nos 150 and [address] with particular reference to overlooking.

The appeal property is a large, detached dwelling, which is locally listed and is therefore a non-designated heritage asset (NDHA). The dwelling has a distinctive mono-pitched roof, which is divided into two parts linked by a lower, single storey flat roof section.

The combination of the building’s long shape extending to the rear, mono-pitched roof, squat nature, use of horizontal cladding, and the front window design, result in a horizontal emphasis to the design of the building. Part of the front upper floor sits on columns and this, in combination with the three-dimensional shape of the building, and the larger wall to glazing ratio, give the building a striking appearance. This unusual design stands out from other houses within the street and, insofar as they relate to this appeal, these aspects contribute to the significance of the NDHA.

The appellant has referred to alterations that had previously been undertaken to the property from the original design of the dwelling. However, there is no substantive evidence before me of any such matters. From the evidence before me, the flat roofed linking element was originally set back from the side elevation of the rear section and would, in this regard, have contributed to the distinctive divide between the front and rear parts of the dwelling.

The proposed ground floor infilling extension between the distinctive front and rear parts of the building, the first floor glazed balustrade and the vertical panelling screening would, in combination, significantly erode the appearance of two distinctly divided elements. The upper elements would be visible from [address] and would result in the appearance of a continuous built form flowing between the two mono-pitched roofs. Moreover, the proposed use of vertical cladding would erode views of the historic fabric of the building, in a manner that would be at odds with the horizontal emphasis associated with its original design.

The proposals seek several alterations, some being more minor than others. Cumulatively, these would considerably erode the authenticity of the original design, to the detriment of the overall appearance of the NDHA.

I therefore find that the proposals would have a harmful effect on the character and appearance of the host property, a NDHA. Paragraph 203 of the National Planning Policy Framework (the Framework) states that the effect of an application on the significance of a NDHA should be taken into account in determining that application. In weighing applications that directly or indirectly affect NDHAs, a balanced judgement will be required having regard to the scale of any harm or loss and the significance of the heritage asset.

The proposals would provide a good level of accommodation built to modern standards and would improve the external amenity space associated with the dwelling. Moreover, the introduction of the screen cladding between the two distinctive parts of the building would screen angled views from Bedroom 4 toward No [address]. There would also be some minor social and economic benefits from the construction works. Overall, these benefits are modest and as such, the harm to the NDHA would, in my balanced judgement, be unacceptable.

As such, I find conflict with the requirements of Policies BE1 and HE1 of the Hillingdon Local Plan: [name] – [name] (2012) (LP1), Policies DMHB3, DMHB11, DMHB12 and DMHD1 of the Hillingdon Local Plan: [name] - Development Management Policies (2020) (LP2), Policy HC1 of the London Plan (LP) and the provisions of the Framework, when taken together and insofar as they relate to this main issue. These say, amongst other things, that development proposals affecting heritage assets, and their settings, should conserve their significance, by being sympathetic to the assets’ significance and appreciation within their surroundings.

The proposals would, by the introduction of the cladding screening and glazed balustrade, formalise the flat roof area as a large external amenity space. This would be accessed from the bedroom and landing at the top of the stairs.

The elevated nature of the flat roof would allow views toward the side of No [address] and the window on its side elevation. The elevated nature, size and secured treatment through the cladding and balustrade would, in my view, result in a level of use and activity that would feel invasive to the occupiers of No [address]. I have reached this conclusion noting that there would be very limited views of the rear garden of this neighbouring property.

The vertical screen cladding proposed would ensure that there would be no overlooking toward No [address] from the flat roof amenity space.

I therefore conclude that the proposals would have a harmful effect on the living conditions of the occupiers of Nos [address] with particular reference to overlooking. As such, I find conflict with the requirements of Policies DMHB11 and DMHD1 of the LP2. These say, amongst other things, that development proposals should not adversely impact on the amenity, daylight and sunlight of adjacent properties and open space.

The proposals would not accord with the development plan when read as a whole and I find there to be no material considerations, that would indicate that the decision should be taken other than in accordance with it.

For the reasons given above, the appeal is dismissed.