Appeal 3275235

The appeal is dismissed.

Following the submission of this appeal, the property and the remainder of the terrace at [address] were listed [name]. The Council notified the Planning Inspectorate of the listing and the appellant was afforded the opportunity to comment.

Given the chronology, there is no related listed building consent application or appeal for me to consider. However, this does not prevent me from considering this planning appeal on its own. [name] allowed this appeal, it would have been a matter for the parties to address regarding listed building consent.

The main issue is the effect of the development on the character and appearance of the host building, the adjoining terrace, and the Camden Town Conservation Area.

The appeal property at [site address] is located in the middle of a terrace of five properties, many of which have been subdivided into flats. The terrace dates from 1834 and is three storeys plus basement with butterfly roofs to each property. These roofs, with their distinctive valley shape, have survived with relatively little alteration. The front elevation of the terrace is rusticated stucco and yellow stock brick, with cast iron balconies at first floor and timber sash windows. The appeal property is particularly grand at the front with an arched first floor window and flanking pilasters rising to a parapet cornice. The terrace’s rear elevation is plainer, but it is possible to appreciate the sawtooth silhouette of the butterfly roofs from [address]. As a result of these architectural and historic details, the property and the terrace are attractive historic buildings.

The property and terrace are located within the Camden Town Conservation Area. This conservation area incorporates the commercial centre of [address] and residential streets either side. These two elements combine to reveal the development of the Camden area, particularly in the first half of the 19th century as London expanded northwards. The residential parts comprise historic terraced housing of similar size and architectural style. The quality and consistency of this housing contributes greatly to the character and appearance of the conservation area as well as its significance. Due to their attractive and relatively unaltered external appearance, the property and the terrace make a strong and positive contribution to the conservation area.

Many residential properties in the conservation area have been subject to mansard roof extensions on top of earlier butterfly roofs. It is not possible to know exactly when or why such extensions took place, but many appear well-established and seemingly carried out around the same time along a number of adjoining properties. Others, such as the recent extension at the listed [address], may have been permitted given existing extensions on neighbouring properties. These roof extensions form part of the conservation area, but this does not mean that they are automatically acceptable as each case should be assessed on its own merits.

The appeal property and the terrace are unusual in terms of the survival of their roof structure. While public visibility of a roof is not necessarily key, it is possible to see the butterfly roofs from [address] while along [address] the consistency of the unbroken roofline is apparent. The conservation area appraisal seeks to preserve the diversity of historic rooflines. It notes that fundamental changes to rooflines, insensitive alterations, poor materials, intrusive dormers, or inappropriate windows can harm the historic character of the roofscape and will not be acceptable. The Camden Design Guide notes that roof alterations or additions where there is an unbroken run of valley roofs or where complete terraces have a largely unimpaired roofline are likely to be unacceptable.

The development has been amended during the application process to give the angles of the mansard extension a more traditional appearance. It would use materials to match the existing property and would also be set behind the parapet at the front and rear. The windows would mimic the shape and size of existing windows below. However, the development would result in the erosion of the butterfly roof structure. Due to its bulk and height, the extension would project significantly above the existing roofline with the party walls and chimneystack also raised upwards. This would result in a highly visible and intrusive extension when seen from either [address] or [address]. It would detract from the relatively unaltered quality of the property and terrace.

In terms of the conservation area, the development would result in harm to the significance of this heritage asset. The harm would be less than substantial but still of an important magnitude given the quality of the external appearance and unbroken roofline. Paragraph 202 of the National Planning Policy Framework (NPPF) states that less than substantial harm should be weighed against the public benefits of the proposal, while Policy D2 of the Camden Local Plan 2017 (CLP) requires these benefits to convincingly outweigh such harm.

The development would provide additional accommodation space and assist with the range of housing provision as promoted by NPPF paragraph 60 and Policy H2 of the London Plan 2021. However, it would only be an additional bedroom and bathroom and so this benefit carries very little weight. NPPF paragraph 120(e) supports opportunities to use the airspace above existing properties, but also states that upward extensions should be consistent with the prevailing height and form of neighbouring properties and the overall street scene and be well-designed. The development would not achieve this and so this benefit carries very little weight. Thus, there are no public benefits that would outweigh the harm to the significance of the conservation area.

For reasons similar to those set out above, the development would also cause less than substantial harm to the significance of the property and terrace as a listed building. The above public benefits would be insufficient to outweigh that harm. However, for the avoidance of doubt, the development would be unacceptable in terms of the main issue alone.

In conclusion, the development would have a harmful effect on the character and appearance of the property, the terrace, and the conservation area. Therefore, it would not accord with [name] D1 and D2 which, amongst other things, seek development that respects local context and character, preserves or enhances heritage assets including conservation areas, and provides public benefits that outweigh any heritage harms. The development would also not accord with NPPF paragraph 202.

Given my overall decision, it has not been necessary for me to consider the impact of the development on the living conditions of neighbouring occupiers. However, even if I were to conclude that there would not be any harm in terms of this matter, it would count as a neutral factor in the overall balance.

For the above reasons, and having had regard to all other matters raised, I conclude that the appeal should be dismissed.