Appeal 3322507

The appeal is dismissed.

The main issue is the effect of the proposal on the character and appearance of the host property and surrounding area.

No [site address] is a two-storey mid-terrace dwelling with a two-storey outrigger to the rear. The appeal site is located on a relatively long residential street which consists of a variety of house designs and styles. However, the row of five dwellings within which the appeal property is located are similar in external appearance, with a largely unaltered roofscape, and this row of properties currently makes a positive contribution to the character and appearance of the street scene and area in general. The appeal site is not within a Conservation Area, but is situated between the boundaries of the Telford Park and Hyde Park Conservation Areas.

The front elevation of the appeal property is finished in red brickwork, with attractive stone detailing to the forward projecting two storey bay window. The low-pitched roof is finished in concrete tiles and the ridge line runs from the front to the rear of the dwelling, however this roof is predominantly screened from ground level by a gable parapet feature to the front of the property.

The appeal proposes a mansard roof extension set behind the retained gable parapet feature, with the ridge line of the proposed mansard roof set above, and running perpendicular to, the existing ridge line of the property.

Relevant guidance is contained within the Council’s Building Alterations and Extensions Supplementary Planning Document (2015) (SPD). This states that in line with Policy Q11 of the Lambeth Local Plan 2020-2035 (2021), all roof extensions must be respectful of the character of the existing building and that changes to roofs that would be detrimental to the appearance of the building or group will be resisted.

The SPD also states that the Council supports the principle of optimising attic accommodation through the use of roof additions and mansards, within the constraints of achieving subordination and protecting the design integrity of the host building.

Even with its set back from the parapet, the proposed mansard roof extension, by reason of its siting, size and height above the existing ridge line, would be visible above the front gable parapet. The proposed massing would appear overly bulky and dominant when viewed from the street and would detract from the unbroken rooflines found on this row of five terrace properties. The proposal would not appear as a subordinate addition and would introduce an incongruous form of development which would harm the architectural integrity of, and be out of keeping with the appearance of, the host property and other dwellings within this row.

As such, whilst the design and specification of the proposed mansard roof accords with the specific technical design advice contained within the SPD for this type of development, for the reasons detailed above the proposal would have a detrimental visual impact on the host property, the group within which it is located and wider area in general. The proposal therefore fails to accord with the guidance contained within the SPD.

My attention has been drawn to two planning applications, and a lawful development certificate, that have been granted by the Council for roof extensions within the vicinity of the appeal site. Whilst each application is judged on its own merits, I have reviewed these cases and do not consider that they are comparable to the appeal proposal as they do not propose the exact same development. Most noticeably none of these approved developments result in roof extensions that would exceed the original ridge height of the property in the way that the appeal proposal would. As such I attribute limited weight to these approved proposals in my determination of this appeal.

Furthermore, reference has also been made, including comments from interested parties, to various other roof extensions, including mansard roofs, within the wider area. I have not been provided with all the details of these various alterations and it is therefore unclear if these are original features, have planning permission or when they were constructed. Nevertheless, and in any case, on my site visit I observed that these examples were not directly comparable to the appeal proposal, nor are they located within the same terrace row as the appeal property which currently has a largely uninterrupted roof scape. As such, again these other roof alterations in the wider area carry limited weight in my determination of this appeal proposal.

Accordingly, I conclude that by reason of its siting and massing, the proposed roof extension would significantly harm the character and appearance of the appeal property, the terrace row within which it is located and the surrounding area. The proposal is therefore contrary to Policies Q2, Q5 and Q11 of the Lambeth Local Plan (2021) which together seek to ensure, amongst other things, that proposals have a design which positively responds to the original roof form of the host building, do not unacceptably dominate the host building, respond to positive aspects of the locality in terms of built form, and that roof additions and mansard roofs should not harm the architectural integrity of the original building or its group.

I acknowledge the comments raised by interested parties that the proposal would allow the existing occupants to extend their property and continue to reside in the area. However, based on the evidence before me I am not satisfied that an alternative scheme could not achieve the improvements required by the appellant without having a harmful impact upon the character and appearance of the host property and surrounding area.

I also note the appellant engaged in pre-application discussions with the Council prior to submission of the planning application. However, these pre-application discussions are not determinative in my consideration of this appeal proposal.

The proposal therefore conflicts with the development plan when taken as a whole and there are no material considerations that indicate a decision should be taken otherwise than in accordance with the development plan. Accordingly, for the reasons set out above, I conclude that the appeal should be dismissed.