Appeal 3337487

The appeal is allowed and planning permission is granted for the erection of a single-storey rear extension, enlargement of an existing cellar, and a side/rear roof extension incorporating rear mansard style roof extension at [site address] , in accordance with the terms of the application, Ref: 2023/2995, dated 8 August 2023, and the plans submitted with it, 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: 23025_P1_09 rev F; 23025_P1_10 rev F; 23025_P1_11 rev F; 23025_P1_12 rev F; 23025_P1_13 rev F; 23025_P1_20 rev F; 23025_P1_21 rev F; 23025_P1_30 rev F; 23025_P1_31 rev F; 23025_P1_32 rev F.

All external materials used in the construction of the development hereby approved shall match the type, texture, tone, colour, size and profile of those used on the existing building and shall be retained as such.

The roof area of the development hereby permitted shall not be used as a balcony, roof garden or similar amenity area and furthermore, no balustrades, railings or other means of enclosure or means of permanent access shall be erected on this area.

Prior to the installation of the air source heat pump, details of the appearance, location, screening, noise impact and predicted carbon savings from the air source heat pump shall be submitted to and approved by the local planning authority to show how the renewable energy carbon savings are to be achieved. The air source heat pump shall be installed in accordance with the approved details prior to the occupation of the development and retained and maintained as such unless otherwise agreed by the local planning authority.

Prior to the commencement of above ground works, details of the appearance, location, orientation, total area and predicted carbon savings from the photovoltaic panels shall be submitted to and approved by the local planning authority to show how the renewable energy carbon savings are to be achieved. The photovoltaic panels shall be installed in accordance with the approved details prior to the occupation of the development and retained and maintained as such unless otherwise agreed by the local planning authority.

The main issue in this case is the effect of the proposed side/rear roof extension on the character and appearance of the host property and the wider Wandsworth Common Conservation Area (CA).

No 17 is a two-storey dwelling situated on the north side of [address], close to its western end. It lies within the CA. In common with most of the houses along the road, it has a slim two-storey side extension, and is effectively the end property in a long terrace of properties that are connected by similar side extensions. The extensions are set well back from the front elevation to give the appearance in the street scene of a row of semi-detached dwellings. The Council has indicated no significant issues with most of the proposals, such that the main issue relates purely to alterations to the roof of the host property, which would include a hip-to-gable extension and the creation of a rear mansard-style roof extension to create additional living accommodation the roof space.

Policy LP1 of the Council’s Local Plan 2023 (LP) indicates that the scale, massing and appearance of a development should provide a high-quality, sustainable design that enhances and relates positively to the prevailing local character and the emerging character (where the context is changing). Policy LP3 of the LP indicates that development proposals will be supported where they sustain, preserve and, wherever possible, enhance the significance, appearance, character, function and setting of any heritage asset and the historic environment. Policy LP5 sets out that any roof extension that is visible from the public realm should be sympathetic to the style of the building and in keeping with the character of the locality. In relation to rear extensions, these should be subservient to the original host dwelling and avoid appearing as overly dominant.

The Character Appraisal for the CA indicates only that [address] comprises mainly two and three storey buildings with single and two storey canted bay windows. The buildings are predominantly of gault and yellow brick with red dressings to the windows. Some have parapets with eaves cornicing, others decorative cornices and string courses. Issues identified for this part of the CA include houses that have been altered unsympathetically through painting, rendering and pebble dashing brick facades, and with replacement windows having inappropriate patterns and materials.

The Council’s SPD on Housing (2016) indicates that the pitch (steepness) and the shape (gabled or hipped) of a roof are important features and should be retained. In particular hipped roofs on semi-detached pairs of houses or on end of terraced houses are often characteristic features and must always be retained. It is rarely possible to change a hipped roof to a roof with a gable end without spoiling the appearance of the house and harming the appearance of a conservation area.

The Council contends that the proposed development, by reason of its scale, design and location, would be unsympathetic and incongruous. It would appear overly dominant and relate poorly to the host building, the adjacent hipped roof semi-detached property and the wider local streetscape. The appellant notes the existence of a number of similar extensions to properties in the immediate vicinity and that the proposal would, therefore, complement the variety of extensions approved along [address]. Furthermore, it would appear that amendments have been made to the original scheme in an attempt to overcome many of the potentially negative issues raised during the course of discussions with the Council on the proposal.

To the west of No 17 are two pairs of semi-detached dwellings (Nos 9 -15) with a gap between the two pairs. There is just a very narrow gap between No 15 and the appeal property, which is built up to the boundary with No 15. The proposed roof extension would involve the building up of the side boundary wall, but it would not reduce the width of the gap between the two properties. Through the gap, there is an existing limited view of a dwelling on [address] at the rear, but this view would not be affected and is, in any case, of little significance to the area.

There are a number of rear extensions to houses in the immediate vicinity of the appeal property including the neighbouring No 19, along with Nos 21, 25 and all of Nos 29 to 37. These appear to be similar in scale and general design to that proposed for No 17, such that the existence of such extensions has emerged as a characteristic feature in the street scene around the appeal property.

In common with these other examples in the vicinity, the extension at No 17 would be set well back from the front elevation of the house and would not affect the front part of the existing hipped roof of the property, which would remain a prominent visual feature. The extension would also be set down by a small amount from the current ridge height of the house. The set back and set down nature of the extension would ensure that it appeared as a subordinate feature to the host property. Moreover, the narrowness of the gap between the appeal property and No 15, together with the sloping nature of the mansard style element of the roof towards the rear of the house, would further reduce its overall visibility within the street scene.

The Council acknowledges the existence of other similar examples in the area but contends that the appeal property is effectively an end-terraced house, while its close relationship to the adjacent No 15, which has a hipped roof, would result in harm to the streetscape. I disagree. Although the earlier examples pre-date the Council’s recently adopted LP, the established character along this significant length of the road is now one where such roof extensions are common and, in my opinion, they are not prominent or harmful to the street scene. I note that the Council has accepted that interpretation in its own reports on these recent extension proposals.

While the proposed roof extensions at No 17 would be on the end of the ‘terrace’ of houses on this side of the road, they would not be readily visible from the street. By virtue of the topography of the area, No 17 is set a small amount below the level of No 15 and this, along with the fact that the extension would be set well back from the front elevations of both houses, would mean that it would be largely screened from all viewpoints except immediately opposite the small gap between the two properties. Furthermore, since the neighbouring No 19, which appears as the other half of a pair of semi-detached houses with the appeal property, also has a similar rear roof extension and the proposal at No 17 would, therefore, effectively balance the visual appearance of the pair within the streetscape.

The Council has referred to a recent appeal decision relating to the dismissal of a proposed roof extension at a house on [address] to the rear. However, the circumstances of the two properties are different, including with regard to such matters as gaps between houses, the positioning of chimneys, and the general lack of any other similar roof extensions on [address]. I do not consider this decision to represent a precedent for the current proposal.

In conclusion, I find that the proposal would not appear uncharacteristic in the area and would not be harmful to the street scene. By virtue of its set back and set down nature it would not appear over-dominant, prominent or incongruous, and it would not be harmful to the character or appearance of the host property, the neighbouring properties, or the wider street scene along [address], where similar roof extensions are a common feature. On this basis, it would preserve the character and appearance of the CA, and would not conflict with Policies LP1, LP3 or LP5 of the LP, nor, in this case, with the general thrust of guidance on roof design in the SDP.

I have attached a condition relating to plans because it is necessary that the development shall be carried out in accordance with the approved plans, for the avoidance of doubt and in the interests of proper planning. I have attached a further condition relating to materials in the interests of the character and appearance of the CA. I have attached a condition restricting use of the flat roof of the rear extension in the interests of protecting the residential amenities of the occupiers of neighbouring dwellings. Finally, I have attached conditions relating to the proposed air-source heat pump and solar panels in order to achieve appropriate appearance and sustainability standards. The submitted plans indicate that conservation-style rooflights would be used in the front roof slope and so I do not consider that a separate condition is necessary with regard to this matter.