Appeal 3334758

The appeal is dismissed.

The application form described the proposed development as “Single-storey rear/side extension, hip-to-gable roof extension and rear dormer”. The council changed this to the description used in the heading above. I have adopted this description as it more clearly describes the development. The appeal form described the development as retrospective, and this is correct, since the development has been carried out. I have therefore added this to the description of the development to reflect this.

The officer’s report notes, in relation to the erected single storey extension, that while moderately larger than that approved, it would remain of suitable scale and design, and uses appropriate materials, and is therefore a subservient addition to the property. As the scheme is located at the rear of the property, it does not result in any impact on the appearance of the street scene, and an array of single storey rear extensions in various sizes have been built in the surrounding area. Therefore, the main issue in this case is the effect of the roof extension on the appeal dwelling, the street scene and the character and appearance of the Wandsworth Common Conservation Area.

The starting point is the legislation and planning policy. Section 72 of the Planning (Listed buildings and Conservation Areas) Act 1990 requires that special attention shall be paid to the desirability of preserving or enhancing the character or appearance of the Conservation Area.

The parties are familiar with development plan policies, so that I will simply say that the following policies are the most relevant. Policy LP3 states that development proposals will be supported where they sustain, preserve and, wherever possible, enhance the significance, appearance, character, function and setting of any heritage asset. Policy LP5 requires that householder development: “respects and/or complements the form, setting, period and detailing of the host building, uses matching or complementary materials, and would be visually subservient to it”, and The second part of the policy requires that: “an extension, dormer window or other alteration to a roof is confined to the rear of the building, and where it is visible from the street scene, it would be sympathetic to the style of the building and would be in keeping with the character of the locality”.

Policy HC1 of the London Plan states 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”.

[name] are consistent with the National Planning Policy Framework (the Framework). Paragraph 205 of the Framework (December 2023) states that “When considering the impact of a proposed development on the significance of a designated heritage asset, great weight should be given to the asset’s conservation (and the more important the asset, the greater the weight should be), irrespective of whether any potential harm amounts to substantial harm, total loss or less than substantial harm to its significance”. Paragraph 208 adds that, “Where a development proposal will lead to less than substantial harm to the significance of a designated heritage asset, this harm should be weighed against the public benefits of the proposal including, where appropriate, securing its optimum viable use”.

The appeal site is a two-storey, terraced dwelling, with a rear two-storey outrigger, located on the northern side of [address]. Whilst the dwelling is terraced, the appearance from the highway is essentially that of a semi-detached house; the connecting element is set back and only seen down the narrow gap between neighbours. The surrounding area consists of properties of a similar scale and design.

The application site is within the Wandsworth Common Conservation Area. Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990, requires that, with respect to any buildings or other land in a conservation area, when considering whether planning permission should be granted, special attention shall be paid to the desirability of preserving or enhancing the character or appearance of that area. In this context, "preserving", means doing no harm.

The planning officer’s report explains that the appeal dwelling has previously been granted permission for side and rear roof dormers to the main roof slope (ref: 2022/0958). I have been supplied with the drawing (No.3648/1) that illustrated this development. This shows a flat roofed dormer with the front cheek rising from the mid-point of the hip, in line with the ridge. It is then shown to wrap around the rear part of the hip to form a rear dormer with the roof set a little below the ridge line. The rear elevation of the permitted dormer is very similar to that built. From the road, the permitted dormer would look like a simple side dormer.

However, the works carried out on site do not accord with this approval. The hip to gable extension creates an extended ridge line of approximately 5.7m in width, terminating in a slate clad vertical gable end, and one rooflight has been installed on the extended main front roof slope. But the rear element of the dormer extension is close to being in conformity.

The appellant argues that side dormers are not a superior design approach compared to hip-to-gables. The side dormers, in his view, appear more awkward, cluttered and clumsy. Either way, it is clear that side roof extensions of one kind or another are well established features of the streetscene and roofscapes in this area, mainly dormers, but also more than a few examples of hip-to-gable extensions.

The side dormer permitted by the council on the appeal dwelling is certainly a very much better design than a good number of other examples in the area. Some of these other examples might be considered to be less satisfactory visually than a hip-to-gable development. However, the appeal development is harmful to the appearance of the pair that share the same hip form – the appeal property and its neighbour at No.32, and in particular, the loss of the diagonal line of capping tiles running up to the ridge, which is a feature of the hip. There is a simple elegance to this form, which would not be removed by the permitted dormer, but has been replaced by an incongruent gable end in the appeal development.

I consider that the loss of symmetry and the clear display of the hip slopes from the street, that results from the appeal development, is harmful to the appearance of the appeal dwelling, the street scene and the character and appearance of the Wandsworth Common Conservation Area. This amounts less than substantial harm to the significance of a designated heritage asset.

In accordance with paragraph 202 of the Framework, this harm should be weighed against the public benefits of the proposal. Clearly the appellant and his household benefit from the extension as constructed, and allowing the appeal would be a further benefit to them in not having to revert to the permitted scheme. However, these factors do not amount to a public benefit.

For these reasons, the appeal will be dismissed.