Appeal 6000940

The appeal is dismissed.

The main issue is the effect of the proposed development on the character and appearance of the host property and the immediate area.

The appeal site relates to a two-storey mid terraced property located on [address]. There is a 90-degree turn on [address] to one side of the appeal property, where a gap between buildings allows views of part of the rear roof slope of the appeal property. In the surrounding area, there are some rear dormer roof extensions, including at the adjoining property (no 37), and at no’s 33 and [address] within the same terrace the appeal property is part of. Although otherwise on this terrace of properties the rear roof slopes are largely unaltered.

I have been made aware of an appeal decision1 for a dormer roof extension at the appeal site, that was dismissed for reasons which included it being harmful to the character and appearance of the host property and the immediate area. The appeal documentation indicates that this proposed dormer roof extension would be marginally narrower than the dismissed proposal (set in from the outer sides by approximately 0.3 metres to either side), but a bit closer to the appeal property’s eaves height (0.2 metres above the eaves height), along with some fenestration changes.

As the appeal property is a flat, it does not have any permitted development rights for dormer roof extensions, so there is no fall-back position in this respect.

[name] 4, Building Alterations, Extensions and Retrofit, dated August 2023 (SPD) says new box dormer extensions should be subordinate 1 Appeal Ref: APP/N5660/W/23/3320846 to the host property (so the original roof remains dominant), and bulky construction details should be avoided. The proposed development is not a linked dormer extension, or any form of mansard roof extension, it is a box dormer roof extension, and it has been assessed as such.

The proposed dormer extension in terms of its significant width, projection from the main roof ridge and its height, would overwhelm the rear roof slope of the appeal property, leaving very little of it remaining and it would not appear subordinate. Its large scale and boxy design would harmfully contrast with the unaltered rear roof plane of the host property, creating a wholly discordant feature, that would be seen from [address] to the side of the appeal site, also harming the terrace it is part of, and the character and appearance of the immediate area.

Whether the existing dormer windows nearby were permitted development or not (the Council say they do not have planning permission), their presence has not altered my findings in this case, nor do they justify the harmful effects of the proposed development.

I have been made aware of a planning permission granted by the Council for what is said to be a similar dormer roof extension at No. [address]. That property is terraced, but it differs from the appeal property in that it is much wider resulting in a larger rear roof width, it also has a different built context including the adjoining road layout, so it is not directly comparable. [name] can appreciate the appellant’s comments about the consistency of the Council’s decisions, that other decision has not led me to conclude differently in this case.

Even though the proposed dormer extension could be constructed in matching materials, this would not address the identified harm. I also note that the Council has not raised objections to the proposed rooflights to the front elevation, and I see no reason to disagree. Nevertheless, they are an integral part of the conversion of the roof space and are not capable of being separated from the rear dormer extension, so a split decision would not be appropriate in this case.

I therefore conclude that the proposed development would be harmful to the character and appearance of the host property and the immediate area, and it would be contrary to policies Q5 and Q11 of the Lambeth Local Plan 2020–2035, adopted September 2021, that amongst other things require the design of new development to positively respond to the original architecture and roof form, not to unacceptably dominate the host building, and for dormer extensions to be subordinate (below the ridge and set in from the eaves and flanks) so that the roof remains dominant. In addition, there would also be conflict with the SPD as set out above.

I therefore conclude that the proposal conflicts with the development plan taken as a whole, and there are no other considerations, which outweigh that conflict. For the reasons outlined above, the appeal should be dismissed.