Appeal 3280316

The appeal is allowed and planning permission is granted for installation of a mansard roof extension for additional bedroom at second floor level, replacing 2no rooflights in the rear roof slope. Alterations to the roof of back addition to incorporate a flat roof with parapet. Erection of railings and timber privacy screen around the flat roof at second floor level to the rear and side elevation in connection with its use as a terrace at [site address] in accordance with the terms of the application, Ref 2021/01472/FUL, dated 30 April 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: 001 – Site plan, 002 - [name] plans, 003 - [name], 004 - Proposed Floor Plan and 005 - [name].

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. Any new materials shall accord with the terms of the application.

The raised party wall of the roof terrace at second floor level hereby approved shall not project more than 1700mm above the adjacent finished floor level.

The development hereby permitted shall not be occupied or brought into use until the 1.7m high timber privacy screen to the side elevation as indicated on the approved drawings, measured from the finished floor level of the terrace has been installed. It shall be permanently retained as such thereafter.

The Council’s appeal questionnaire indicates that the appeal site is within a conservation area. However, the evidence, including the submitted Crabtree Conservation Area Plan, indicate that the appeal site is adjacent to, but outside the Conservation Area, as extended in November 2018. I have dealt with the appeal on that basis.

The main issues are the effect of the appeal proposal on the character and appearance of the host property and on the setting of the Crabtree Conservation Area; and the effect of the second-floor development on the living conditions of neighbouring occupiers.

It is proposed to erect a rear 'pod' extension with glazed doors over part of the existing back addition. Its remaining roof would be altered to form a terrace with 1.7m timber privacy screens to the side and 1.1m high metal railings to the rear.

To the rear of the terrace containing the appeal property (No 37) is a large recreation ground. Between the two is the boundary of the Crabtree Conservation Area. This area of the recreation ground adjacent to the terrace contains a deep area of trees and other planting. As a result of its screening effect and the small gardens to the terraced houses, close views of their rears are restricted. Views of the upper part of No 37 are from some distance away and within the recreation ground. The proposed development would be at the rear and would not be visible in the street-scene as the Council states.

The 'pod' and terrace combined would occupy the entire, altered, roof of the back addition. The extension would comprise 50% of this area and would align with the adjacent extension at No 39. Policy DC4 of the London Borough of Hammersmith and Fulham Local Plan (LP) controls the standard of design of extensions and alterations and highlights the need to protect terraces of uniform appearance. A full depth terrace at No 55 was approved under superseded planning policies. The roof extension covering 50% of the back addition of No 39 was approved recently. There are also a number of other roof developments on the rear of the terrace, including large extensions at Nos 45 and [address] at No 35. The rear of the terrace could not therefore reasonably be described as unaltered. Furthermore, a recent, unimplemented, planning permission at the appeal site allows for alterations to the roof of the back addition including the erection of a privacy screen and railings to enable its use as a terrace.

The appeal site context therefore includes a variety of rear additions and roof terraces and within this context, I conclude that the cumulative bulk and massing of the extension and the timber privacy screen would not be out of keeping with the character and appearance of the appeal property, the terrace as a whole or its wider surroundings and would not be visually dominant. It would preserve the character and appearance of the host property and the setting of the Crabtree Conservation Area and would not harm its significance. Overall, the proposal complies with [name] DC1 and DC4, which in summary encourage high quality design, and LP Policy DC8 which among other things requires the protection of the historic environment. There would be no conflict with the design objectives of the National Planning Policy Framework (the Framework). As the appeal site is not within the conservation area, the Council’s Planning Guidance SPD (SPD) [name] CAG3 relating to development in such areas is not relevant to this appeal.

The use of roofs of back additions as external amenity space could in some circumstances result in harmful noise and disturbance. However, the proposed terrace would be under the 15 sqm identified as acceptable within the SPD, and I conclude that its use would not result in unacceptable levels of noise and disturbance.

In terms of overlooking, the Council indicates that it limits the depth of structures above back additions to no more than 50% of the roof in order to protect the outlook from any rear habitable room window which is lower than the proposed extension. In this case I have considered whether the outlook from No [address]‘s first floor and lower-level rear windows would be impacted so as to create an unacceptable sense of enclosure, including an assessment of ‘the angle of unobstructed visibility’.

Due to its small size, sloping end wall, high level, the recent approval for the terrace and its relationship with the neighbouring properties, I conclude that the extension, screen and the use of the proposed roof terrace would not create an unacceptable sense of enclosure and would be little different to what has already been approved. It would not harm the living conditions of adjoining occupiers. Furthermore, the privacy screen would prevent overlooking. For these reasons the proposal would comply with [name] DC4 and HO11 and [name] HS7 of the SPD.

For the avoidance of doubt and in the interests of proper planning, I have identified the approved drawings in a condition. External materials should match the existing to safeguard visual amenities. I have imposed a condition restricting the height of the raised party wall of the roof terrace, also in the interest of visual amenities. In order to protect the living conditions of neighbouring occupiers, I have imposed a condition preventing the occupation of the extension or bringing into use the terrace until the privacy screen has been provided. In some instances, I have amalgamated the proposed conditions in the interests of brevity and/or amended the Council’s suggested wording to more accurately reflect the nature of the appeal proposal.

For the reasons set out above, the appeal should be allowed.