Appeal 3295648

The appeal is allowed and planning permission is granted for the construction of roof extension on rear roof slope at [site address] in accordance with the terms of the application, Ref 2021/4932, dated 27 October 2021, 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: 04-57; 05-57; 06-57; 07-57; and [name] (dated 27 Oct 21).

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.

The main issue is the effect of the proposal on the character and appearance of the host property and wider terrace.

The appeal property is an end of terrace dwelling, constructed in the late 1990s. The properties either side of the appeal site and on the opposite side of [address] and [address] form part of the same development and comprise of rows of terraced townhouses interspersed with detached houses of a similar design. Gaps between the rows of terraces and detached dwellings are narrow. Many of the properties have been subsequently altered and extended, including several with roof extensions and dormers.

The proposal is for a mansard roof extension to the rear roof slope of the dwelling. A similar mansard roof extension is also proposed to the rear of [address]. I am also the appeal Inspector for that proposal1.

Whilst there are no other rear roof extensions within the terrace that includes the appeal property, there is a mansard type roof addition on the detached house that is immediately adjacent to the terrace, and on several other detached dwellings within the same estate. I also observed that some of the townhouses within nearby terraces have ‘box type’ dormers of varying scale and designs on their rear elevations.

The Council’s Housing Supplementary Planning Document (2016) (SPD) provides design guidance for residential extensions, including dormers and roof extensions. This guidance states mansard style additions to the rear slope of mid-terraced houses where the roofs are subdivided by party walls are usually acceptable where these cannot be seen from the street. However, for houses at the end of a terrace and on a corner, it states that the rear mansard style addition should be avoided. The SPD also states that it is unlikely that the addition of mansard roofs will be considered as an acceptable alteration to roofs, which are visible from public areas within conservation areas.

The appeal site falls outside of the Clapham Common Conservation Area (CA) which is located over 80 metres to the east. The rear elevation of the appeal property is not publicly visible from the CA and proposed roof extension would not therefore have any material effect on the setting of the CA or views from it.

Whilst the appeal property is on the end of the terrace, the gap between it and the adjacent end of terrace property (No 55) is narrow such that the proposed roof addition would not be visually prominent from the street. The existing terrace is divided by several party walls, including between Nos 57 and 59. The proposed extension would not be visible from any public areas due to the lack of gaps between the closely knit dwellings along [address] to the rear of the site. The proposal would therefore be compliant with the aims and objectives of the SPD.

I acknowledge the Council’s concern that within the estate, only the detached houses display mansard style roof additions. Whilst this may be the case, given the similarities in their design and the lack of visual separation between the detached houses and the rows of terraces, the proposed mansard roof addition would be seen in the same context as the mansard on No [address] and on several of the other detached houses within the estate. Furthermore, there are many examples in the wider surrounding area of mansard type roof additions.

Whilst the raising of the eaves on the rear elevation would result in the removal of the second-floor dormers, the windows would nonetheless remain aligned and the removal of this architectural feature would not, in my opinion, be harmful to the overall appearance of the terrace. I also note that the second-floor rear dormers are not common to all of the dwellings within the estate nor do they appear to be a particular feature of the surrounding area. The distinctive contrasting horizontal banding would also be retained, ensuring visual continuity. The proposed extension would be constructed in appropriate, matching materials. 1 Appeal ref. APP/H5960/D/22/3295649

The proposed mansard roof would extend across the width of the dwelling and would be adjacent to that also proposed at No [address]. Given the context of the appeal site and the presence of other mansard type roof additions, I do not consider that the scale or design of the proposal would unacceptably disrupt the continuation of the terrace or be unsympathetic or out of character with the area. I am therefore satisfied that it would comply with Policy DMH5 of the Wandsworth Local Plan Development Management [name] (adopted 2016) (LP) which amongst other things, seeks to ensure that extensions are well designed, uses appropriate materials and is no so large that it dominates and competes with the original building.

In conclusion on this main issue, the proposal would not have a harmful effect on the character and appearance of the host property and wider terrace. Thus, it would comply with Policies DMS1 and DMH5 of the LP and the Housing Supplementary Planning Document (2016) which together seek to ensure development integrates with its surroundings and is sympathetic to local character.

For the reasons set out above, and having regard to all other matters raised, I conclude that the appeal should succeed.