Appeal 3340861

The appeal is dismissed.

Although the application forms describe the site location as [address], all the rest of the application information, including the red line site plan, confirms that the proposal relates to both 161 and [address]. The Council also determined the application on the basis of relating to both 161 and [address]. I shall therefore also consider the proposal on that basis.

The main issue in this appeal is the effect of the proposal on the character and appearance of the existing properties and on the character and appearance of the Osterley Park Conservation Area.

The appeal properties are a pair of semi-detached houses on the south side of [address] and facing towards the southern boundary of Osterley Park. The properties along this part of [address], including the appeal properties, are predominantly wide semi-detached pairs of differing designs, which largely fill the width of their plots. The appeal site is within the designated heritage asset of the Osterley Park Conservation Area. The significance of the Conservation Area focusses on the historic Osterley Park but extends to include the surrounding residential development, particularly along its southern side.

Both houses appear to have been previously extended and whilst there are some differences between the two, including in terms of material finishes, the semi-detached pair are broadly symmetrical in form. The proposed extensions at first floor would extend to the rear the central part of the two houses on either side of the common boundary. The roof would be projected over part of the rear extension with a new flat roof area and the addition of dormers.

The existing semi-detached pair are substantial properties which largely fill the width of their plots. However, the scale and massing of the overall built form is modified by the articulation of the rear elevations and the set back of the central elements in relation to the projecting elements. At roof level the dormers are modest in scale in relation to the main roof and do not therefore dominate the rear roof slopes.

By comparison, the depth of the proposed first floor extensions together with the greater depth and scale of the extended roof would lead to a substantial increase in the overall bulk and massing of the built form. This would result in very solid and cumbersome rear elevations, both at first floor level as well as roof level and much of the existing articulation which assists in reducing the scale and massing of the built form would be removed. As a result of both the depth of the first floor extensions and the form and massing of the roof extensions, the development as proposed would not respect but would harm the proportions, character and appearance of the two properties.

Although the extensions would be at the rear and would not be seen from the front along [address], there would be glimpsed views from [address] and from neighbouring properties. In such views the over dominant extensions to the existing properties would detract from the character and appearance of the locality and would not preserve the character and appearance of the Osterley Park Conservation Area.

I therefore conclude that the proposed extensions would not respect but would harm the character and appearance of the existing properties and would not preserve the character and appearance of the Osterley Park Conservation Area. This would conflict with Policies CC1, CC2, CC4 and SC7 of the Council’s adopted Local Plan, the Council’s Residential Extension Guidelines and the National Planning Policy Framework and in particular Sections 12 and 16 all of which, amongst other matters, seek a high quality of design which respects the local context and protects the character and appearance of designated heritage assets.

The appellant has drawn my attention to extensions granted along [address] and in particular to a permission granted by the Council for extensions to a property further along [address] where the Council acknowledged that it would exceed the thresholds set out in the Council’s SPD guidelines. Each proposal must be considered on its individual merits, but in so far as the information has been made available to me, I have taken it into account. However, it does not appear to me to be directly comparable with the proposal before me and does not therefore lead me to a different conclusion. In that case, the Council found that although the proposed extensions would not accord with the SPD guidelines, the proposed development would preserve the character and appearance of the host property and wider area. My conclusion in respect of the proposals before me is, and for the reasons set out above, that the proposed development would not preserve the character and appearance of the host properties and wider area.

I have taken into account the family related reasons for seeking the extensions. However, I am not persuaded that additional accommodation could not be provided in a more sensitive way given the harm I have concluded. These personal reasons do not therefore outweigh the harm I have found.

The proposal would not accord with the development plan and there are no other material considerations to override this finding. For the reasons given above and having regard to all other matters raised, including in representations, I conclude that this appeal should be dismissed.