Appeal 3319627

The appeal is allowed and planning permission is granted for alterations including erection of an extension above the two-storey back addition at [site address] , Wandsworth, London, [postcode] in accordance with the terms of the application, Ref 2023/0063, dated 9 January 2023, subject to the following conditions:

The development hereby permitted shall begin not later than 3 years from the date of this decision.

The development hereby permitted shall be carried out in accordance with the following approved plans: [name] A01, A02, A03, A04, A05, A06, A07, A08, A09, A10, A11 and A12.

The materials to be used in the construction of the external surfaces of the development hereby permitted shall match those used in the existing building.

Prior to completion of the development the window in the side elevation at second floor level of the development shall be obscure-glazed and non-opening (unless the parts of the window which can be opened are more than 1.7 metres above the floor of the room in which the window is installed). The window shall be maintained and retained as such.

My formal decision uses the description of development that was used on the Council’s decision notice and which was repeated by the appellant on the appeal form. This is a better reflection of the proposed works compared with that which was given on the application form and which I have quoted in the banner heading above.

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

The appeal property is a two-storey, semi-detached dwelling located within a residential area comprising properties of similar age and appearance in a tight-knit urban grain. The property has a two-storey, subservient outrigger with a hipped roof and which is mirrored by the attached dwelling at No 27, with a central ridge running along the common boundary between both properties. No 29 has an existing ‘box-like’ dormer extension to the rear main roof slope. The proposal would see this extended by turning through 90-degrees and projecting it along the side roof slope of the existing outrigger.

The ‘box-like’ addition to the shallow side roof slope of the outrigger would be set marginally up from the eaves and away from the rear elevation of the dwelling, with its height significantly above the ridge line to the rear projection and equivalent in height to the ridge over the dwelling’s main roof. It would amalgamate with the existing rear dormer to create a large, flat roof extension at second floor level that would unquestionably alter the form and shape of the dwelling’s existing roof, which would become virtually indiscernible when viewed from the rear. In my assessment, it would appear as the kind of top heavy and dominant addition that the Council’s Housing Supplementary Planning Document (SPD) generally advises against.

However, I am mindful of an extant planning permission for No 29 that was granted in October 2022 (Ref 2022/3513) for works described as ‘Alterations including erection roof extension above two-storey back addition’. These approved works are for a very similar scale of development but described by the Council as being a ‘mansard addition’. A true mansard roof would have two pitches to each roof slope. In this case, the approved works are for a roof extension with steep mono-pitched slopes to the side and rear, with a flat crown over. When compared with the vertical sides to the roof extension now proposed, to my mind there is little meaningful difference to distinguish between the scale and form of the approved roof extension and the appeal proposal. Moreover, I note that the SPD, when discussing how to minimise the impact of a roof extension on neighbours, suggests that a vertical face set up from the eaves may be an acceptable option. The design approach of the current appeal proposal is therefore not explicitly ruled out by the SPD guidance.

In addition, the appellant has drawn my attention to several examples in the locality where vertical faced roof extensions, of significant scale, have been built in the immediate vicinity of the appeal site. I saw these for myself when viewing the context of the property from its rear garden. The rear elevations of properties in [address] face the appeal site at reasonably close quarters. These do not have rear outriggers, but the significant majority that can be openly seen from No 29 have dominant and vertical faced dormer extensions that have transformed the original roof profiles of these properties. More significantly, other vertical faced roof extensions to properties along [address] were evident, including over outriggers, particularly at Nos 15 and 35. In those cases, the original roof configurations were overtly changed.

Overall, notwithstanding some apparent degree of conflict with the SPD guidance in general relating to the design, placement and size of roof extensions, in light of the extant planning permission for No 29, and the large and prominent roof extensions that have become established features of the rear garden confines of the locality, I am satisfied that the proposal would not appear so dominant that it would be unsympathetic or incongruous in its setting. I therefore conclude that there would be no harm to the character or appearance of the area. As such, there would be no conflict with the permissive criteria that are given for alterations and extensions within Policy DMH5 of the Council’s Development Management Policies Document (DMPD), adopted March 2016. The proposal would therefore display the design quality that is required by DMPD Policy DMS1 and the Council’s Core Strategy (2016) Policies PL1 and IS3 to enable development to respect local distinctiveness and to be successfully assimilated into its setting. For these same reasons I find no conflict with the similar requirements of emerging Policies LP1 and LP5 of the Wandsworth Publication Version Local Plan.

A condition specifying the relevant plans is necessary as this provides certainty. In the interests of maintaining the character and appearance of the area, a condition is required to ensure that the proposal is finished with materials to match the existing.

To safeguard the privacy of neighbouring occupiers, I agree with the Council that a condition is required to ensure that the new side facing window at second floor level is fitted with obscure glazing and is fixed shut up to an appropriate height.

For the reasons given, I find that there would be no harm to the character or appearance of the area. In the absence of any other conflict with the development plan, and having regard to all other matters raised, the appeal is allowed.