Appeal 3330622

The appeal is allowed and planning permission is granted for the addition of a garage and a basement to the dwelling house in accordance with the terms of the application Ref 232996HH, dated 21 July 2023, subject to the conditions set out in the attached Schedule.

A revised version of the National Planning Policy Framework (the Framework) was published on 19 December 2023, during consideration of the appeal. Having regard to the changes in the Framework and to the comparatively minor scale and nature of this appeal proposal, I consider that consultation on this revision is not necessary.

The main issue is the effect of the proposal on the character and appearance of the house, [address] and the setting of the Norwood Green Conservation Area.

[site address] is a recently constructed detached house set at the end of a suburban cul-de-sac of mainly semi-detached houses of varying architecture. It is off-set from the end of the street and sits back within a large plot and behind a high wall and gate, so that it is not prominent in views from [address]. Its lower sections are furthermore largely screened in views from the footpath that runs along the site frontage. The conservation area lies to the rear of the site. The proposal is to build a flat roofed garage and games room extension to the side, with a new basement underneath the side extension and extending well to the rear. The Council raises concerns about both the above and below ground parts of the proposal.

The flat roofed section would be reasonably modest in scale and straightforward in design. It would fit in with the area’s mixed character in general and more specifically with No 1’s architecture, which is more contemporary in style than its neighbours. It would be seen when the front gate is open but even then would only be a minor feature, set back from the street and the footpath. It would not crowd the site’s boundaries or block any important views.

Turning to the issue of the basement, London Plan Policy D10 states that Councils should establish Development Plan policies to address the negative impacts of large-scale basement development. The issue is not specifically addressed in the other development plan policies cited by the Council in this case, but the Supplementary Planning Document SPD4 [name] says that in streets where basements and lightwells are not a traditional feature the excavation of a basement can have a significant impact on the appearance of the house and the street scene. SPD4 adds that the proposed form and design of the original house will be considered, along with the impact of adding a basement on neighbouring properties and on the structure of the house.

The basement would be discreetly sited and designed, with an internal access through the side extension and no external access. Although it would take up much of the depth of the garden, its scale would not be readily apparent - being marked only by 2 sets of rooflights at ground level. It would not appear to crowd or overdevelop the site. [name] saw no lightwells or other evidence of basement development on [address], this particular basement would not look out of place in its context.

The development would be screened from the conservation area sufficiently so that there would no significant effect on its setting. I conclude that the proposal would not harm the character or appearance of the house or [address] or the setting of the conservation area. It accords with London Plan policies D3, D4 and D10, the Council’s Development Management Development Plan Document policies 7.4 and 7B and SPD4, which aim to secure good design that complements the local street sequence, building pattern, scale, materials and detailing and preserves or enhances the setting of conservation areas.

I also take into account the further objections of local residents, noting that none of these additional points has been put forward by the Council as a reason for refusal. London Plan Policy D10 draws attention to the potential for basement development to impact land or structural stability. In this case, the basement would be near to the boundary with No 1b next door, but with sufficient spacing so that mitigation measures should be possible. Structural issues like this are also covered by other legislation including the Building Regulations and the [name] etc Act 1996, but the Council’s report and London Plan policy D10 refer to the need for a Basement Impact Assessment. This can be covered by a planning condition requiring approval before development begins, so that any issues can be taken on board.

Excavation and construction work will inevitably cause some disturbance locally, but this would be short term and could at least in part be dealt with through the Basement Impact Assessment. I saw at my site visit that adequate and appropriate space is and would be provided for off-street parking. Although there are concerns about other future uses of the house, I must base this decision on the proposal in front of me. Finally, any breaches of planning control that might occur during development will fall to the Council to deal with.

I impose a condition specifying the relevant plans to provide certainty. A Basement Impact Assessment is needed, as explained above. This has been agreed by the Appellant. Another condition requiring the use of matching materials is needed to protect local character and appearance. Finally, a condition restricting use of the new flat roof is necessary to protect privacy at No 1b.

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

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

The development hereby permitted shall be carried out in accordance with the following approved plans: Location Plan, [name] P2, A 101+ A 201/P2 ([name]), Basement Plan P2, [name] P2, A103 + A203/P2 ([name]), A106 + A206/P2 (Sections 1), A107 + A207/P2 (Sections 2), A108 + A208/P2 ([name]), A109 + A209/P2 ([name]), A110 + A210/P2 ([name] 1) and A111 + A211/P2 ([name] 2).

Prior to the commencement of development, a basement impact assessment shall be submitted to and approved in writing by the Local Planning Authority. This document shall include the assessment of potential impacts on the structural stability of the house and neighbouring houses, vibration, disturbance, drainage and groundwater issues, with a method statement and mitigation measures as necessary. The approved method statement and mitigation measures shall be implemented in full and the mitigation measures shall thereafter be retained.

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

No part of the roof of the extension shall be used as or altered to form a balcony, roof garden, roof terrace or similar amenity area.