Appeal 3307833

The appeal is dismissed.

The main issue is whether the proposed development would preserve or enhance the character or appearance of the [address]/[address] Conservation Area (CA).

The appeal site comprises a four-storey (including basement) mid-terrace dwellinghouse with a hidden flat roof behind a parapet. The parapet runs along the length of the terrace and some of the buildings have chimneys and side parapets, including the appeal property. Traditional sash windows are a feature of the properties in the terrace. Some of the buildings close to the appeal site have mansard roofs but there are also other nearby buildings, including terraced rows of dwellings, where mansard roofs are not a feature.

Having regard to the [address]/[address] Conservation Area Design Guidelines 2002, the significance of the CA is notable for its architectural consistency, homogeneity, and historic interest of the late Georgian and early Victorian terraces. The appeal property is designated as a locally listed building as part of the terraced row, recognised for its important contribution to the street scene. It also makes a positive contribution to the CA due to its traditional form and location amongst a relatively uniform terrace.

The proposed mansard roof extension, because of its wide, boxy design and the raised side parapets and chimneys, would be a bulky and discordant addition to the appeal property. Further, the wide opening on the front elevation would not be consistent with the proportions and alignment of the existing traditional windows on the street. The proposal would not be particularly prominent when viewed from the front of the property at street level because of the height of the buildings. However, in longer views from the opposite side of [address] and from the [address]/[address] junction, the roof extension would be highly prominent. Therefore, the proposal would compromise the consistency and unity of the terrace, causing harm to the significance of the appeal property, terrace row and wider street scene of the CA.

In addition, visible from [address] and [address], the small square rooflights set into the proposed mansard roof on the rear elevation would not reflect the traditional style and profile of the windows within the rear elevation of the appeal property, or those that are prevalent within the terrace, and would appear discordant.

There are other mansard roof extensions within the terrace at 61 and [address] but the front elevations of these are not visible from longer views so are not comparable to the proposal. The top part of an existing mansard roof extension at [address] (No 59) is visible from several locations in [address], and its position and size has broken the unity and consistency of the terrace row. Nevertheless, while the proposed mansard roof extension would be positioned in the same short terrace row as No 59 and would have a similar set back, overall height and profile, it would be located separate to No 59 and would not fill in a clear gap or provide a visual connection with it. As such, the proposal would further harm the unity and consistency of the terrace row and wider street scene.

The appellant has referred to other examples of mansard roof extensions in the area but as these are in terrace rows with varied building heights, many existing mansard extensions, or the extensions are not visible from the street, they differ from the appeal proposal.

For the reasons set out and having regard to the duty under Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990, the proposal would neither preserve nor enhance the character or appearance of the CA, although the harm would be less than substantial. Paragraph 202 of the National Planning Policy Framework (the Framework) states that less than substantial harm to the significance of a designated heritage asset should be weighed against the public benefits of the proposed development. I have not been directed to any public benefits in this case. Therefore, I conclude that the proposed development would conflict with the National Planning Policy Framework.

Overall, the proposal would not preserve or enhance the character or appearance of the CA, contrary to Policy HC1 of The London Plan The Spatial Development Strategy for [name] 2021 (the London Plan), Policies CS8 and CS9 of [name] 2011 and Policies DM2.1 and DM2.3 of Islington’s Local Plan: Development Management Policies June 2013. Together, these seek to conserve or enhance the historic significance of heritage assets, including when altering existing buildings in conservation areas, and require development to reflect and make a positive contribution to the local character and distinctiveness of an area.

The proposal would conflict with the Urban Design Guide Supplementary Planning [name] [address]/[address] (CA03) Conservation Area Design Guidelines January 2002 where it seeks to resist roof extensions, rooflights and associated party wall alterations which are visible from the street or public area, including long views from side streets.

Policies D1 and D4 of the London Plan relate to Boroughs being required to undertake and use area assessments in planning for growth and to processes and actions required to deliver good design. I do not find these policies to be directly relevant to the proposed development.

For the reasons given above, the proposal would conflict with the development plan as a whole and there are no material considerations, including the Framework, that would outweigh that conflict. Therefore, the appeal is dismissed.