Appeal 3354980

The appeal is dismissed.

On 12 December 2024, a revised National Planning Policy Framework (the Framework 2024) was published with an amendment issued on 7 February 2025. The Framework 2024, as amended, does not raise any new matters that are determinative to the outcome of this appeal.

The main issues are the effect of the proposed development on: • the living conditions of the occupiers of [address] with particular regard to outlook, light and visual impact; and • on the character and appearance of the host building and the local area.

The proposal is to enlarge and alter the rear projection of the appeal property, which is a mid-terrace dwelling within a predominantly residential area. The first floor of the projection is to be extended rearwards to line up with the existing ground floor element. A new second floor is also to be introduced with a mansard style roof and dormer windows. The external materials to be used would match those of the existing building.

The Council has recently granted planning permission for a similar type of extension to the rear of No 14. Compared to the proposal before me, the approved scheme includes a shorter and therefore smaller second floor component with the sides of the mansard style roof set at a slightly shallower pitch.

The flank wall of the proposed extension would be along the shared boundary with the attached property to one side of the site, which is [address]. In the rear elevation of No 12 is a first-floor window from which a considerable expanse of new brick wall would be visible at reasonably close range. Having carefully viewed the rear of No 12 from the site, I am persuaded that the proximity of what would be a substantial blank wall just to one side of this window would represent such a significant change that it would result in an over-dominant impact on outlook.

There would also be some loss of daylight and sunlight to the room served by the first-floor rear window of No 12 due to the presence of the new built form just to the south. The effect of overshadowing would be evident during a major part of the day and be most pronounced in winter months when the sun is lower in the sky. The loss of natural light would accentuate the visual impact of the proposal. It would cause the extended dwelling, as sought, to overbear on the occupiers of No 12 when seen from their first-floor rear window.

That the proposed extension would project beyond a line drawn at 45-degrees from the centre of the first-floor window of No 12, even if marginally, does not allay my concern with regard to the harmful impact on that window. Imposing a condition to require an assessment of the effect of the new development on light, as suggested by the appellant, would be inappropriate in this instance because the acceptability of the appeal scheme is reliant on the outcome of this exercise.

On the first main issue, I therefore conclude that the living conditions of the occupiers of No 12 would be materially harmed by the proposal. Accordingly, it is contrary to Policy LP2 of the Wandsworth Local Plan 2023-2038 (LP) and the Council’s Supplementary Planning Document Housing (SPD) insofar as they aim to safeguard residential amenity.

The site lies within the [address] Conservation Area (CA), which is mainly residential in character. The CA derives its significance as a designated heritage asset from the rich variety of buildings within it that often form a diverse and picturesque townscape. I have paid special attention to the desirability of preserving or enhancing the character or appearance of the CA, as required by Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990.

Although not identified as a designated heritage asset, the appeal dwelling typifies the traditional style, built form, architectural features and proportions of many properties within this part of the CA. As such, it adds to the sense of general unity and broad cohesion in the general appearance of the existing buildings. For these reasons, No 14 positively contributes to the character and appearance of the CA.

When seen from the rear of the site, there would be a 2-storey elevation to the rear projection with a sizeable mansard with steep sides above, creating 3 levels in all. There would be no increase to the footprint of the host building. The top of the new addition would be set below the main ridgeline. Even so, the proposal would add disproportionate scale and bulk at a high level to the existing rear projection. With the new built form in place, the rear projection would no longer be subordinate to the original house, nor would it avoid an over-dominant extension when seen from the back garden of No 14. Consequently, the appeal scheme would conflict with LP Policy LP5 and the guidance within the Council’s SPD.

By significantly adding to the scale and mass of the rear projection, the appeal scheme would overwhelm the traditional style and distort the proportions of the existing house. It would also result in the loss of the pitched roof to the existing rear projection that appears to form part of the original building. As a result, the intrinsic character of the dwelling would be spoilt.

None of the proposal would be seen from [address] given its position at the back of the main house. However, when viewed from the rear garden of No 14 and neighbouring properties, the new extension would draw the eye as an overly large and bulky addition that would relate poorly to the scale of the main dwelling. That impression would also be apparent in a more distant view along [address].

The appellant has drawn my attention to several other rear extensions to properties further along [address] and on [address], with photographs and some background details provided. In my experience, it is rare that direct parallels can be drawn between one site and another because local circumstances often vary. In this instance, there are it seems to me significant differences in terms of the individual proposals and their relationship to the host building such that preclude meaningful comparisons with the appeal scheme. In any event, each development should be assessed on its own merits, which I have done.

On the second main issue, I conclude that the proposal would be an overly large, dominant and obtrusive development that would detract from the character and appearance of the host building and the local area. As such, the appeal scheme would diminish the contribution of No 14 to the significance of the CA as a designated heritage asset and so fail to preserve its character and appearance. It is therefore contrary to [name] LP1, LP3 and LP5 and the Council’s SPD. These policies and guidance broadly aim to ensure that residential extensions and alterations respect or complement the form of the host building; are not overly dominant; and sustain, preserve or enhance any heritage asset.

The harm caused by the new extension would be localised and so the effect on the CA would be less than substantial. In those circumstances, the Framework 2024 states that the harm should be weighed against the public benefits. Once complete, the proposal would provide additional living space and improve the internal layout of the dwelling. It also makes efficient use of the space available in a location that is accessible. While these benefits are largely private, a dwelling with good sized rooms that would meet the needs of a family would in due course positively contribute to the wider housing supply. However, these public benefits do not outweigh the significant harm that I have identified.

The occupiers of No 12 raise no objection. However, my assessment takes into account future as well as existing occupiers of this adjacent property.

The development sought conflicts with the development plan. There are no material considerations, including the Framework 2024, which indicate that the decision should be taken otherwise than in accordance with the development plan. For the reasons set out above, I conclude that the appeal should be dismissed.