Appeal 3346658

The appeal is dismissed.

The main issue is the effect on the character and appearance of the appeal dwelling, the terrace of which it forms part and that of the local area.

The appeal dwelling is a four storey 19th Century terraced house with small palisaded front garden and raised ground floor, to the rear is a recent lower ground floor extension. It forms part of a terrace of similar brick built properties with a continuous parapet line, with butterfly roofs behind. The appeal proposal is for a zinc clad mansard roof extension that would be set back approximately 1 metre from the front parapet, and very slightly back from the rear sloping parapet. It would be the full width of the property, sitting between the party walls to adjoining properties, which would be extended upwards, retaining the existing chimney pots.

The houses in the terrace are generally unaltered, retaining much of their original architectural features, including butterfly roofs, and are currently without any mansard extensions. Consequently, the retained originality and continuous and uninterrupted parapet line are features of the terrace. This results in a cohesive street elevation to the terrace that makes a significant contribution to the character and appearance of the local area.

Paragraph 124 of the National Planning Policy Framework (2023) (the Framework) sets out that planning policies and decisions should allow mansard roof extensions on suitable properties. This paragraph further sets out that this is where their external appearance harmonises with the original building, including extensions to terraces where one or more of the terraced houses already has a mansard.

The proposed mansard extension would have a large single area of glazed doors to the front, with smaller more traditionally formed windows to the rear. These would be set in to a zinc clad roof profile with only limited sloping elements to the top part. Along with the proposed extensive area of glazed doors, this would contrast with the traditional architectural appearance of the appeal dwelling, particularly the existing fenestration. This would result in a discordant architectural appearance, which would be contrary to the design guidance for mansard extensions set out in the Council’s Residential Extensions and Alterations Supplementary Planning Document (2009).

The proposal would result in the loss of the original butterfly roof form of the appeal dwelling, although the rear associated sloped parapet that follows the existing butterfly roof form would be retained. The proposed mansard would be set back from the front parapet; however, I find that it would be visible in street views of the appeal dwelling, especially the extended party walls. Whilst less evident in direct frontal views, it would be more apparent in more tangential and wider street views from the street, as well as from properties opposite and to the rear.

In these views, the proposed mansard would appear as a single stand-alone addition, which, due to its scale, height and discordance with the appeal dwelling and the existing roofscape, would appear as an unduly apparent and incongruous addition to the appeal dwelling and the terrace of which it forms part. The loss of the existing butterfly roof form and presence of the proposed mansard would detract from the contribution that the existing original roofscape makes to the character and appearance of the appeal dwelling, the terrace of which it forms part and that of the local area.

The appellant has made reference to other mansard extensions in the local area. Those that are in the same street as the appeal dwelling are on properties on the other side of the street. These properties demonstrate a wide variety of height, scale and architectural expression. As such, they differ considerably in appearance from the appeal property and the unified appearance of the terrace of which it forms part. Other mansard extensions on terraced properties in nearby streets appear to vary considerably in age. Only very limited details have been provided of more recent examples1 in [address] and [address] referred to by the appellant.

As such I do not find that the examples of mansards provided by the appellant provide direct exemplars for the appeal proposal and would have been considered on their own merits. I have likewise considered the appeal proposal on its own merits, which is a main tenet of the planning system. I have, therefore, only afforded these limited weight in my considerations.

For these reasons, I find that the proposal would result in substantial harm to the character and appearance of the appeal dwelling, the terrace of which it forms part and that of the local area. This would not accord with Policy LP1 of the Hackney Local Plan (2020), Policy D3 of the London Plan (2021) and Paragraph 135 of the Framework. Collectively, these seek to ensure that development is of high design quality, responds to local character and context and is compatible with the existing townscape 1 Planning Ref: 2021/1019 and 2021/1037

Whilst the proposal would result in a larger house with an additional bedroom, this is primarily a private benefit to the occupiers. There would also be potential benefits regarding insulation and resulting energy efficiency, although the proposal is not the only way that this benefit could be achieved. Consequently, I find that the limited public benefits of the proposal do not outweigh the harm that I have identified above.

For the reasons given, I conclude that the appeal should be dismissed.