Appeal 3313020

The appeal is dismissed

The main issue in this case is whether the development would preserve or enhance the character or appearance of the [address] (Mortlake) Conservation Area, and whether it would harm its significance as a designated

The significance of the conservation area lies partly in the manner in which it still reflects its evolution from a small village on the edge of London to its incorporation into the built-up area. The variety in the ages and styles of buildings contribute to this significance and comprise a key element of its character and appearance.

No 20 and the 2 houses to the east are a short row of matching villas from the period of the conservation area’s significant development following the arrival of the railway. When seen from the front, their scale, form and detailing mean they make a positive contribution to the character, appearance and significance of the conservation area both individually and collectively. From behind, the contribution of these houses to the historic context is reduced, as there is less detailing and they all have a large modern dormer on the main rear roof slope. However, on this elevation each has a 2-storey subservient projecting outrigger that is currently free from discordant additions. These provide a certain rhythm to this row of houses and contribute to maintaining its historic form.

The proposal would extend the dormer to a point roughly halfway down the projecting rear outrigger. The roofworks at the property would therefore be encroaching onto a new area of the dwelling’s roof. Furthermore, the development would sit uncomfortably on this outrigger, for while it would be set in slightly from the eaves, it would rise significantly above the ridgeline with the matching outrigger at [address]. Moreover, although of a similar form and materials to the existing rear dormer, it would not relate well to the appearance of the remainder of the house, but rather would make the roofworks more striking.

Overall, I find it would not be of a scale and design that accorded with that of the existing building or respected its form. Rather, even when taking account of the dormer now present, it would be a discordant element that dominated the original roof and interrupted its profile, appreciably eroding the dwelling’s existing historic character and appearance as a result.

Therefore, by adversely affecting a building that contributes positively to the conservation area, I consider the development would cause harm to the conservation area’s significance, and would fail to preserve its character and appearance. However, given the scale of the works and their location, I find this harm to the significance would be less than substantial.

In coming to this view, I am aware that the works could only be seen from outside of the conservation area, when looking from the gardens to the west, or from on [address] around the modern flats and garaging that have been built behind these 3 dwellings. However, it would nonetheless be visible, particularly as it would be at roof level, and I see no reason why regard should not be given to the harm to the conservation area from these views, such as they are.

I am aware too that there is an extant but unimplemented permission for a new building at [address], which would have a similar arrangement at second floor level to what is now proposed for No 20. In relation to this, the appellant referred to the judgement of North Wiltshire District Council v Secretary of State for the Environment (1993), which sought consistency in decision-making between one Inspector and another. However, the permission at No 14 was not granted on appeal, but rather by the Local Planning Authority.

In any event, the above judgement accepted it did not follow that like cases had to be decided in the same way. Rather, where an Inspector chose not to follow an earlier decision, he had to give his reasons for doing so. I acknowledge the works at No 14 to be a material consideration in this case, as they will have some bearing on the character and appearance of the area. However, while that building would have an ‘L’-shaped treatment at second floor level, its rear arrangement below would be appreciably different to that of 16, 18 and [address], as the first floor would extend across the full width of the plot with no rear outrigger. It would therefore be apparent, to some degree, as a distinct and separate form of development to the 3 houses to its east. Moreover, as a new build, it would not be affecting the same historical references as the works at No 20. As a result, I consider the intended roof form on that new property would have a materially different effect on the designated heritage asset, and so does not offer me a basis to find differently in this case

I agree with the appellant that the works would not destroy the appearance, proportions or form of the property, not least because they would not affect the frontage with its detailing. To my mind though this does not mean the works would not cause some harm. I have noted too other dormer features across the conservation area. Some are of a scale or design that enliven the streetscape and enhance the historic context, though others make a less positive contribution to the conservation area’s significance. However, they do not offer a basis for me to consider this particular scheme would not be harmful. I saw too an ‘L’-shaped roof extension on a property on [address], but again that does not lead me to change my findings.

The appellant has contended that decision-makers ‘should only refuse applications to heritage assets where the proposed development will lead to substantial harm to or total loss of significance of a designated heritage asset’. However, paragraph 199 in the National Planning Policy Framework (the Framework) states that great weight should be given to the conservation of a designated heritage asset, and in paragraph 200 it adds that any harm [my emphasis] to the significance of a designated heritage asset should require clear and convincing justification. It therefore makes no distinction between substantial and less than substantial harm. It goes on to say that if less than substantial harm is caused to the significance of any asset, that harm should be weighed against the public benefits. In my opinion it is therefore clear that, unless outweighed by public benefits, less than substantial harm can also be a basis to resist a proposal.

I recognise there would be some benefit arising from the scheme providing more room in the dwelling. Such a claim though would apply to any extension, and I have no grounds to consider the property at the moment provides inadequate accommodation within the housing stock. Therefore, to my mind it does not represent a clear and convincing justification for the works, and does not constitute a public benefit sufficient to outweigh the harm identified.

Accordingly, I find the proposal would not preserve the character or appearance of the [address] (Mortlake) Conservation Area, and would cause less than substantial harm to its significance as a designated heritage asset. In the absence of any clear and convincing justification for this harm and as it is not outweighed by any public benefits, I conclude the proposal would conflict with the Framework, with Policy LP3 in the London Borough of Richmond Upon Thames Local Plan, which seeks to conserve the historic environment, and, insofar as it is a material consideration, with guidance contained in the Council’s [address] Extensions and [name].

I therefore conclude that the appeal should be dismissed.