Appeal 3340252

The appeal is allowed and planning permission is granted for the addition of a single storey mansard roof extension towards the rear of the existing roof, adding a roof terrace towards the front of the property in accordance with the terms of the application [name]/23/06784, dated 13 October 2023, subject to the following conditions:

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, 5703_PA_100B, 5703_PA_101B, 5703_PA_200B, 5703_PA_201B and 5703_PA_300B.

The roof slopes of the extension hereby permitted shall be clad in natural slates. All glazing hereby permitted shall have white painted timber frames and the dormer windows at the front shall be clad and roofed in in lead with double hung sliding sashes. These features shall thereafter be retained as approved.

The extension hereby permitted shall not be occupied until the second floor level rear glazing has been fitted with obscured glass in accordance with details first submitted to and approved in writing by the local planning authority, and no part of that glazing which is less than 1.7 metres above the floor of the room in which it is installed shall be capable of being opened. The obscured and fixed glazing shall be retained in that condition thereafter.

The main issue is whether the proposal would preserve or enhance the character or appearance of the Royal Hospital Conservation Area (RHCA) and the settings of nearby listed buildings.

[address] is a residential mews within the RHCA, lined by a variety of 2 to 4 storey terraced houses, plus the back gardens and garages of some of the much taller, grade II listed buildings fronting onto [address] to the north. The Council’s RHCA Appraisal advises that the buildings on [address] show a range of individual styles and generally have a vertical emphasis. It says that the northern side of the street (which includes No 5) has a mews like character. These houses do not seem to be noted as positive contributors to local character in the Appraisal. A unifying characteristic of the street is said to be the use of traditional materials.

No 5 is a relatively plain, 2 storey, mid-terrace, flat roofed house, sitting next to a 3 storey, flat roofed building (apparently with a roof terrace) at No 3. The proposal is to add a mansard style roof, set back behind a glass balustrade at the front to form a small roof terrace.

No 5 would still be significantly lower in height than No 3. With the mansard extension it would form a more gradual, stepped transition between the heights of Nos 3 to 7. The mansard would be set back from the street frontage to minimise its visibility in the street scene and in some views would be seen against the blank second floor level wall of No 3. It would not appear against the skyline due to its situation and the taller buildings around it. There are already mansard roofs within this varied street scene so this well-designed proposal using traditional materials would not be at odds with the local architecture. No 5 would remain visually subordinate to the much more substantial listed buildings on [address], to the rear and would not affect views of their frontages.

I conclude that the proposal would preserve the character and appearance of the conservation area and the settings of the nearby listed buildings. It accords with policies CL1, CL2, CL3, CL4, CL6, CL8 and CL11 of the Local Plan and the National Planning Policy Framework, which seek to secure high quality design for all development, including roof alterations, that contributes positively to the townscape and protects the special architectural or historic interest of conservation areas and listed buildings. In coming to this conclusion, I give special attention to the desirability of preserving the settings of listed buildings and preserving or enhancing the character or appearance of conservation areas as required by Sections 66 and 72 of the Planning (Listed Buildings and Conservation Areas) Act 1990. The Council also refers to an emerging New Local Plan, but accords that plan only limited weight and does not cite any of its policies in the refusal notice.

I have considered the comments of objectors, particularly in regard to the impact on living conditions at neighbouring properties. This is a tightly developed urban situation, with a high degree of mutual overlooking and overshadowing including gardens and roof terraces. No 5 is at present heavily overlooked, especially by the [address] properties which have windows close to No 5’s rear windows and high level garden terrace. The proposal would add new glazing at the back, which could give close range views into the [address] properties. This new overlooking could be intrusive, but the plans show this glazing to be frosted glass and this could be secured by condition. A similar, but less intense situation applies at the front, where I consider the wider spacing to be adequate to protect privacy, given the already high level of overlooking between properties.

This modestly sized new mansard structure would not be so large or tall that it would unduly interfere with outlook or light to neighbouring properties in this urban situation where most of the buildings are taller than No 5. Concerns about the construction process can be dealt with through other legislation and would not justify withholding planning permission. I therefore agree with the Council that no undue harm would be caused to living conditions at neighbouring properties.

I impose a condition specifying the relevant plans to provide certainty. Specification of materials is necessary to protect local character and appearance. It is not necessary or desirable, however, for railings to be panted black as the Council requests because this would make the proposed glass balustrade more visible. The Council suggests an additional condition requiring the use of matching materials, but that matter is adequately dealt with by condition 3. As set out above, a condition requiring the use of obscure glazing at the back is also necessary, to reasonably protect neighbours’ privacy.

The Council also requests a condition requiring submission and approval of a Checklist and Site Construction Management Plan to help protect the amenity of neighbouring occupiers during construction. This would be a small scale development, however, and no special reason has been put forward to justify such a condition. The development would be subject to other legislation controlling potential nuisance from construction works.

I find that the proposal accords with the development plan for the area. For the reasons set out above, and having regard to all other matters raised, I conclude that the appeal should succeed.