Appeal 3358143

The appeal is dismissed.

The site visit was undertaken by a representative of the Inspector whose recommendation is set out below and to which the Inspector has had regard before deciding the appeal.

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

The appeal site is located within the [address]/[address] Conservation Area (CA). Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (the Act) requires that special attention be paid to the desirability of preserving or enhancing the character or appearance of a Conservation Area.

The CA is characterised by regular terraces of residential properties. The CA derives considerable significance from its architectural consistency, homogeneity and historic interest, which contribute to the area’s character and appearance. The rooflines, particularly on terraced streets, are also a major part of the character of the area, with many of the properties in the local area having hidden valley roofs behind front parapets.

The appeal dwelling is a mid-terrace house with a traditional valley roof with a raised parapet to the front elevation. Towards the rear elevation, the valley roof has a half width brick-built roof structure with a rear brick wall. The appeal dwelling therefore has a distinctive rear roof profile which is made up of the valley roof wall and the rear wall of the roof structure. The downward slope of the valley roof wall creates a gap in the roof profile which adds to its distinctiveness. Appeal Planning Officer APP/V5570/D/24/3358143

The other dwellings in this terrace replicate the form, scale, design and appearance of the appeal dwelling and have a very similar roof design and profile. The architectural consistency and uniform appearance of dwellings on the street, including the front and rear roof profiles, creates a sense of symmetry and balance and therefore makes a positive contribution to the character and appearance of the CA. In relation to the rear elevation, the similarity of the roof profiles results in a distinctive and interesting roof profile pattern which contributes positively to the CA.

The proposal is for a full width mansard roof extension that would extend further forwards than the existing roof structure. It would be set back from the front parapet wall to align roughly with the middle of the front chimney stack, and would be of a similar height to the brick-built part of this stack. The proposed extension would have two new front facing windows, one rear window within the mansard roof and an additional new window within the existing rear elevation at roof level.

The front parapets and part of the front chimney stacks of dwellings in the terrace, including the appeal dwelling, are visible from street level. I also saw on my site visit that a large proportion of the front chimney stack is visible in a long view from [address]. Therefore, given its position, part of the proposed development would be visible from ground level in this longer view. It would be seen projecting above the front parapet wall and, as a result, would disrupt the broad uniformity of the front roofline profile of the terrace, and diminish its contribution to the CA.

The rear elevations and roof profiles of the appeal dwelling and its neighbours are clearly visible from [address], from a private shared yard area to the rear of the terrace and from the rear gardens and windows of dwellings surrounding this yard area. There have been a number of minor alterations made to the half-width brick structures on the terrace, including raising the height of some and inserting windows, but these have not materially impacted the appearance and distinctiveness of the roof profiles.

Although the mansard extension would be set back slightly from the rear wall of the appeal dwelling and a dark colour, it would be clearly visible in the gap in the rear elevation roof profile. It would only be modest in size and the overall scale would be subservient in proportion to the dwelling as a whole. Nevertheless, by infilling this characteristic gap, the proposal would disrupt both the roof profile of the dwelling and the broad uniformity of this distinctive roof profile on the terrace. This would be clearly visible from [address], exacerbating the visual impact of the proposal.

Consequently, the proposed development would not be compatible with the appeal dwelling and would harm the architectural consistency and unity of both the front and rear elevations of the terrace. It would represent a harmful incremental change which would erode the appearance of the terrace, to the detriment of the character and appearance of the CA.

The parties have referred me to a number of examples of proposals in the area for which planning permission has either been approved or refused. The unsuccessful proposals, being Nos 3, 15 and [address], were for extensions of a different design, scale and form than what is proposed in this case so there can be no meaningful comparison between them.

The proposals for No 2 and [address] were approved but, importantly, these dwellings are not sited as close to a side street as the appeal dwelling. Their roof extensions are also set further back than the appeal proposal and did not introduce Appeal Planning Officer APP/V5570/D/24/3358143 a mansard to the front. As a result, they are not clearly visible from the public realm at either the front or rear, so do not have a comparable impact to the appeal scheme.

There are other examples of mansard roof extensions in the area, however they are generally in streets with many such alterations, therefore are seen in a different context to the appeal site. Consequently, the fact that there are examples of rear extensions and alterations in the wider local area does not outweigh the harm the proposed development would cause to the CA.

For the reasons set out above, therefore, the proposed development would not preserve or enhance the character or appearance of the CA. Consequently, the development would not comply with policies PLAN1, DH1 and DH2 of the Islington Local Plan Strategic and Development Management Policies (2023) and Policy HC1 of the London Plan 2021 which aim to conserve and enhance the historic environment and heritage assets.

Further, the proposed development would not comply with the Urban Design Guide Supplementary Planning Document (2017), the aims of the National Planning Policy Framework (Framework) and the [address]/[address] Conservation Area Design Guidance (2002). Amongst other things, these documents seek to ensure that developments preserve and enhance the character and appearance of Conservation Areas and respond to the existing site context. They also emphasise the importance of preserving the architectural unity of rooflines in Conservation Areas and that any alterations to them should be invisible from the public realm.

The proposal relates to only one part of the CA so the harm to the CA as a whole would be less than substantial. Paragraph 215 of the Framework advises that, in these circumstances, this harm should be weighed against the public benefits of the proposal including, where appropriate, securing its optimum viable use.

The development would provide additional living accommodation for the occupiers, but this would be a private benefit. The appellant contends that the proposal includes scope for environmental benefits including reducing carbon emissions and increasing water and energy efficiency, which would be public benefits through the efforts to tackle climate change. While the appellant has listed various measures to be included, it has not been demonstrated that the proposed extension is necessary to achieve all of these, so I give this minimal weight. This would not outweigh the harm caused to the CA, which is a matter of considerable weight and importance.

I have reviewed the representations received both for and against the scheme and have given them due consideration and weight when evaluating this proposal.

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

I have considered all the submitted evidence and my representative’s report and I agree with the reasoning and recommendation. On that basis the appeal is dismissed.