Appeal 3364857

The appeal is dismissed.

The main issue is the effect of the proposal upon the character and appearance of the appeal property and the wider area, including the [address]/[address] Conservation Area.

The appeal property is a three-storey with basement mid-terraced Georgian property set along the west side of [address], a predominantly residential street comprising similar aged and styled properties within the wider [address]/[address] Conservation Area (CA). The Council’s Conservation Area Design Guidelines (CADG), January 2002, describe the CA as a whole as predominantly residential and largely made up of late Georgian and early Victorian terraces. The properties along [address], including No 25, display a high degree of architectural consistency and historic character that typifies the CA’s special character and appearance, and contribute positively to its overall significance as a heritage asset.

No 25 has a shallow pitched roof behind a front parapet. The proposal is to create additional living accommodation within the roof space by raising the ridge height by approximately 400mm and constructing a contemporary styled flat roofed dormer to the rear.

The Council’s Urban Design Guide Supplementary Planning Document (SPD), adopted in 2017, when discussing rooflines in general, advises, amongst other things, that where an existing roof profile has historical and/or architectural importance and/or contributes to an area’s individual character, an alteration is likely to be unacceptable. [name] the SPD specifically advises that roof extensions anywhere along an unaltered roofline will not generally be acceptable. Where a roofline is broken, it advises the scope for roof extensions will normally depend upon three specific criteria, namely :- (i) the number of existing roof extensions and the extent to which the unity and consistency of the roofline has already been compromised; (ii) the length of the terrace; and (iii) terraces within CA’s will also be subject to the detailed consideration of the CADG. For dormer windows specifically, the SPD advises that their design should be in keeping with the original dwelling and relate to the windows of the original house in proportion, detailing and position. It goes on to state that a dormer should be positioned a clear distance below the ridge-line, significantly clear of any boundary parapets, and above the line of the eaves.

By raising the existing ridge-line, the dormer would obviously fail to sit below the ridge-line of the appeal property, or the original ridge-line of the terrace as a whole. Neither, in my judgement, would the dormer be positioned a clear distance below the raised new ridge-line. In addition, it would fail to consider the fenestration pattern of the dwelling’s rear elevation with little respect shown for the architectural composition of the building overall. It would neither line up with the windows below nor strike a reasonable balance as a modest dormer in a central position, which the SPD suggests can be an acceptable approach. By virtue of its contemporary styling with excessive glazing, its overall size and bulk, and its raised profile, I find that it would appear dominant and incongruous within the rear roof slope and out of character with the host building and historic context of its setting.

Both the planning officer’s report and the appellant’s submissions, including within their architect’s original Design, Access and [name] (DASS), January 2025, include extensive lists of past planning applications and decisions to various properties along both sides of [address] considered to be of relevance. Many of these where planning permission has been granted relate to roof alterations to properties within the terrace to the east side of the road, which are numerous. However, I note the Council’s point that the roof profile to this terrace suffered gradual degradation over time which had significantly compromised its original character. Given these circumstances, and whilst I accept that these examples sit within the CA, considering also the fact that they do not fall within the immediate visual context of the current appeal proposal, a point made by previous Inspectors when dismissing appeals for roof alterations at Nos 33 and [address] ([name]/V5570/D/22/3295477 and APP/V5570/W/18/3216754), I attach little weight to how the roof profile of the terrace opposite has evolved for the purpose of this appeal.

There are roof additions and alternative roof profiles to some dwellings within the terrace along the west side of [address]. In particular, Nos 43-53 (odd) at one end of the terrace feature consistent traditional mansard roofs with subservient front and rear dormers. However, they are a distinct group with a form that appears historic and is obviously differentiated from the pitched roof form to the remainder of the terrace.

The appellant has directed me to examples of front and rear dormer windows at Nos 35, 39 and 41. In each of these cases, based upon the information that has been provided to me, the dormers appear modest in scale and set central within the original pitched roof, which retains its visual dominance. I am not persuaded that any roof terraces associated with these, including also an example of a sunken roof terrace highlighted at No 13, have altered the rear roof profile of the terrace as a whole to any significant degree.

During my visit, it was evident to me from street level along [address] that, despite those roof alterations to the terrace that had taken place, there was little visual impact when observed from the public domain. From the rear, when viewed from the appeal property’s enclosed back garden, the visible extent of the terrace’s roofline also appeared largely unbroken and characteristic of the building’s historic origins apart from one obvious and isolated example of a mansard roof extension at No 21. This was granted planning permission in 2016 (Ref P2016/1815/FUL).

I found the rear roof modification at No 21 to be a dominant feature which shows little respect for the architectural composition of the property or wider terrace. The extension may lawfully exist but I do not consider a poor outcome justifies further potential harm. Whilst degradation of the original roof profile to the terrace opposite has justified further changes over time, the original architectural composition of the terrace to the west side of [address] remains largely intact and uncompromised. Changes that have occurred do not suggest to me that a tipping point for inappropriately sensitive change along the terrace has been reached. Furthermore, I note the planning decision for No 21 in 2016 pre-dated the Council’s SPD and adoption of The London Plan 2021 (LP) and the Islington Local Plan Strategic and Development Management Policies September 2023 (SDMP). Further still, from the extracts of the drawings approved that have been provided within the appellant’s DASS, there was no proposed increase to the maximum height of the roof, which was shown on the plans to be consistent and aligned with the ridge lines of both adjoining properties. The circumstances at No 21 do not alter my conclusions as far as they relate to the current appeal proposal.

I accept that views of the proposed changes at roof level would be limited and that there would be no impact upon the street scene along [address]. However, and notwithstanding the large [address] warehouse building which sits at the foot of the appeal site, the rear dormer would not be out of sight and would be seen from the rear garden settings of other properties nearby along the terrace.

Overall, I find that the proposed rear dormer would be unsympathetic to the host building and would fail to harmonise with the predominant roofline along the terrace. It follows that the character and appearance of the CA would be neither preserved nor enhanced.

Having regard to paragraph 212 of the National Planning Policy Framework – December 2024 (the Framework), the harm arising from the proposal to the significance of the CA would be less than substantial. However, this does not equate to a less than substantial objection and any harm to a designated heritage asset requires clear and convincing justification in line with paragraph 213 of the Framework. Furthermore, in line with the Framework’s paragraph 215, such harm should be weighed against the public benefits of the proposal.

Given the statutory duty set out in Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 to pay special attention to the desirability of preserving or enhancing the character or appearance of the CA, I attach significant weight to the harm that I have identified to the historic environment. I am unable to identify any public benefits to the scheme such that the harm that I have identified would be outweighed.

Given my findings, there would be conflict with the Council’s SDMP Policies PLAN1, DH1 and DH2 and LP Policy HC1. Between them these seek to ensure all development is of a high quality that responds and contributes positively to local character and distinctiveness, including the conservation and enhancement of heritage assets. I recognise that the proposed works would provide the applicant with additional space for their family, and that the works would provide improved thermal qualities for the property, but these factors do not lead me to conclude that the decision should be made other than in accord with the development plan.

For the reasons given above, the appeal is dismissed.