Appeal 3351687

The appeal is dismissed.

The main issue is the effect of the development on the character and appearance of [site address] and the surrounding area.

The appeal site (No.3) is a substantial detached house within an established residential area that appears to have been comprehensively developed during the middle decades of the twentieth century. Generally sitting within spacious plots, designs of this period are typically derivatives of earlier Arts and Crafts influences which tend to emphasise the importance of plain-tiled roof form, chimney stacks, and with that, an important absence of classical symmetry. The deployment of traditional materials and details such as rounded, lead-topped, bays with tile spandrels and oriel features as found in the original design of No.3 are similarly evocative.

[address] falls within an area designated as the North Uxbridge Area of Special Local Character (ASLC). Information provided by the Council in that regard does not wholly explain the basis of its designation which is related to Policy DMHB5 of the Hillingdon Local Plan: [name] – Development Management Policies (2020) ([name] 2). However, although the appellant correctly points out that the area is not a designated heritage asset such as a Conservation Area, it is apparent that the designation within the Development Plan is intended to attach significance to the visual form and character of the areas that may have originated from pattern book designs of the post-war ‘[name] popular movement. It is to such considerations that I now turn.

The proposal seeks to add an upper storey to a recently-constructed single storey flat-roofed side extension that currently is apparent but not unduly prominent in the street scene. This recent extension, together with a two storey side extension1 on the opposite (north) side of the original house has already introduced a significant change in the way this house relates to the street such that it no longer sits within its plot, with an associated spaciousness around the houses as was typical of locality originally did, but fills its width. The effect of such change is, cumulatively, to fundamentally change the largely open character of the original development pattern north side extension has introduced a side wing of roof with a similar height of ridge and an unnecessarily continuous eaves line which, taken together, undermines the significance of the original pyramid2 roof whilst falling short of the introduction of an overbearing near-symmetry in the principal elevation to the street scene which would be the result of what is now proposed.

The proposal indicates that the upper-storey extension would be hip-roofed to suit the main ridge height but, due to its depth, would be inconsistently pitched, a factor of the design which, although not likely to be readily apparent in the street scene, nevertheless fails to respect the architectural principles evident in the original arts and crafts-derived designs which, in most examples, expressly avoided classical design principles such as symmetry.

The appellant has drawn attention to previous decisions including, at the dwelling opposite, an appeal3 which has permitted a symmetrical main elevation described as ‘balanced and attractive’. Whilst this description no doubt reflects the different starting point for the dwelling concerned that had plainly been subject to insensitive change and pressure for enlargement, there are many examples in [address] where alteration or additional accommodation has been achieved whilst retaining the essential character of the original design. Policy DMHD1 A(ix) of the [name] 2 is clear that all extensions in Areas of Special Local Character should be “designed in keeping with the original4 house, in terms of layout, scale, proportions, roof form, window pattern, detailed design”. What is proposed at No.3 would fall well short of those objectives as my assessment explains, by cumulatively overwhelming the original built form with a side addition that would further detract from the character and appearance of both the host dwelling and the surrounding parts of the [name].

I therefore conclude, for the reasons given and taking all matters raised into account, that the proposal would conflict with Policy DMHD 1, and [name] 5 and 11 of the [name] 2 which taken together seek to ensure that residential extensions should both harmonise with local context and respect the architectural quality of the original buildings; and therefore, conflicting with the development plan taken as a whole. Consequently, the appeal cannot succeed.