Appeal 3363026

The appeal is dismissed.

In the header above I have used the description of development set out on the Council’s decision notice as it more accurately reflects the proposal before me.

The main issue is the effect of the proposed development on the living conditions of the neighbouring property No [address] with particular regard to daylighting, sunlighting and potential overbearing effects.

The appeal property is a semi-detached dwelling that is one of a pair with No [address] (No 9). The character of [address] is residential made up of predominately semi-detached dwellings that generally have two-storey outriggers to the rear of the buildings.

The appeal proposal comprises a single-storey rear extension. The extension’s rear projection will be staggered, featuring a depth varying between 4 and 5 metres. The section closest to No 9 would extend to around 4 metres in depth and be positioned right up and along the shared boundary between the two properties. The proposed extension would have an off-centre pitched roof, which would be around 3.6 metres at its highest point. The eaves height along the boundary with No 9 would be around 3 metres.

Policy DM10 of the Royal Borough of Kingston upon Thames Local Development Framework Core Strategy 2012 (CS) requires that development consider the amenities of occupants and neighbours, including outlook, sunlight, and daylight. Additional guidance is provided in the Council's Residential Design Guidance Supplementary Planning Document 2013 (SPD).

According to the SPD, rear extensions on semi-detached properties should typically have a depth of 3 to 3.5 metres and heights ranging from 3 to 4 metres. The proposal does not accord with the guidance provided in the SPD in terms of depth. When the 4 metre depth is considered in conjunction with the 3 metre eaves height on the shared boundary with No 9, the proposal would present as a highly visible and dominant structure with a large and blank façade wall.

The visual impact would be further accentuated by the proposal’s significantly greater height compared to the existing fence, which at around 1.8 metres in height does not provide an adequate screen to mitigate the proposal's visual effect. Consequently, the overall scale of the proposal with its 3 metre eaves height would create an unacceptably overbearing structure and undue sense of enclosure to No 9 given it is proposed to be sited right up to and along the shared boundary. This impact would particularly affect No 9’s outdoor space immediately adjacent to where the proposal would be sited.

The proposed increase of 0.5 metres beyond the SPD guidance would for the reasons stated not be a minimal or inconsequential addition. Nor do I find that it would be sufficiently comparable with what the SPD deems acceptable when evaluating the overall impact of the proposal’s height, depth, scale, mass, and bulk on No 9 and within its specific site context.

I acknowledge the examples cited by the appellant of other rear extensions along [address] that have been approved by the Council with similar or greater depths. Of these examples, I note approved plans have been provided for a rear extension at No [address]. Although the depth of this development at No 13 is similar to the appeal proposal, it includes a setback from the shared boundary fence. This setback ensures that the extension at No 13 does not appear overly dominant or oppressive in relation to the neighbouring properties, despite having a depth that does not conform to the Council’s SPD guidance.

It is also not clear whether any of the other examples are comparable to the appeal proposal in terms of dimensions and position on a shared boundary for me to give any significant weight to them in this decision. Consequently, none of the examples cited justify the adverse impact that would arise to No 9’s living conditions from the proposal’s excessively prominent height and depth along the shared boundary.

Concerning daylighting and sunlighting, the SPD states that the 45-degree rule should be used to assess a proposal’s effect on the nearest windows of neighbouring habitable rooms. It is acknowledged that the closest neighbouring ground floor window falls within a 45-degree angle of the proposal. However, the appellant's documentation presents substantial evidence, including floor plans of No 9 and photographs, that demonstrates the closest ground floor window likely does not serve a habitable room. The appellant has also provided evidence indicating that the proposal would affect daylight to the rear of No 9 only during a short period in the morning.

For these reasons, I find that the proposal would not negatively impact No 9's living conditions in terms of daylighting and sunlighting. Nevertheless, the absence of harm regarding daylighting and sunlighting does not justify the overbearing impact on living conditions identified.

I also acknowledge that no objections were received to the proposal and that it is needed to meet the needs of a growing family. Nonetheless, I am still required to consider the impact of the proposal for future neighbouring residents as well as those existing, which for the reasons stated I have found to be unacceptable.

To conclude, the proposal would have an unacceptably overbearing impact on the living conditions of No. [address] due to its height and depth on the shared boundary contrary to Policy DM3 of the London Plan 2021 and DM10 of the CS, which seek to safeguard amenity. The proposal also conflicts with the Council’s guidance for extensions set out in the SPD and would not be consistent with Paragraph 135 of the National Planning Policy Framework that requires a high standard of amenity for existing and future users.

For the reasons given above and considering all matters raised, I conclude that the development does not accord with the development plan and the appeal is dismissed.