Appeal 3351999

The Council has described the application as “construction of ground floor rear infill extensions and loft conversions including rear dormer roof extension to rear roof slope, additional roof extension to rear outrigger roofslope, installation of roof lights, front fencing, front terracing and landscaping works with other associated alterations (resubmission with additional / altered elements)”. As this more accurately describes the works proposed it is used in the decision below.

An updated version of the National Planning Policy Framework (the Framework) was published on 12 December 2024. The relevant parts of the Framework have not materially changed and whilst the parties have not been asked to comment, I am satisfied they have not been prejudiced as a result.

The appeal is allowed and planning permission is granted for the construction of ground floor rear infill extensions and loft conversions including rear dormer roof extension to rear roof slope, additional roof extension to rear outrigger roofslope, installation of roof lights, front fencing, front terracing and landscaping works with other associated alterations (resubmission with additional / altered elements) at [site address] , Blackheath [postcode] in accordance with the terms of the application, Ref 24/1161/HD, 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 accord with the following approved plans: 2301/E101 P1 (existing floor plans), 2301/E102 P1 (existing elevations and section), 2301/G100 P2 (site location plan), 2301/G101 P3 (proposed floor plans), 2301/G102 P3 (proposed elevations and section), 2301/G103 P2 (block plan), 2301/G104 P1 (existing and proposed side (south) elevation).

The materials to be used on the external surfaces of the development hereby permitted shall match those used in the existing building.

It is clear from the Council’s reason for refusal on the decision notice that it is only the cumulative effect of the proposed rear dormers that is objected to and the Council confirms that the other elements, including the proposed dormer within the main rear roofslope, already have planning permission (Ref: 23/4007/HD). Therefore, the main issue is the effect of the proposed dormers on the character and appearance of the host dwelling and surrounding area, including the Westcombe Park Conservation Area.

The appeal site comprises a large, terraced dwelling of Edwardian age which sits in an elevated position relative to the road and pavement. There are a number of steps up to the front door with front garden area comprising a raised bank behind a retaining wall. To the rear is a large two storey ‘outrigger’ extension. The road is predominantly characterised by terraced dwellings, though those to the south of the appeal site are of grander scale and set at a higher level as the road slopes up from north to south.

The Conservation Area Appraisal (2010) (CAA) notes that the conservation area has been built up on the former Westcombe Park estate, comprising of predominantly late Victorian and Edwardian properties, with some later infill. The appeal site lies within a residential area of late nineteenth and early twentieth century origin. A number of the properties are locally listed including those comprising the terrace to the south of the appeal site and some on the opposite side of the road, including numbers 60-64 which lie opposite the site. The significance of this part of the conservation area is mainly derived from the traditional layout and architectural style of the Victorian and Edwardian properties.

The Council’s Urban Design Guidance SPD (2023) ([name]) states that rear dormers are generally acceptable subject to building typology. It goes on to state that they should be well spaced and positioned within the existing roof slope and reflect the position of existing windows below. Guidelines for distances to the ridge, party wall and eaves are set out. It goes on to state that roof extensions should generally follow and complement the pattern and pitch of the main roof and be secondary in scale to the main roof.

The additional roof dormer that is now proposed would be sited within the part of the roof that comprises the junction of the main roof with the rear outrigger. It would be of the same height as the previously approved dormer but would extend to a greater depth. Nevertheless, it would be a relatively small addition in the context of the remaining roof slope area with the majority of the sloping roof of the rear outrigger unaffected. In addition, whilst cumulatively the two dormers now proposed would take up a significant proportion of the main rear roofslope, they would nevertheless be well spaced with the original roof form still discernible.

The UD SPD includes an example of a rear outrigger extension which extends over the whole depth of its roof slope that is considered unacceptable due to its size and overbearing nature. However, the proposal in this case would be much smaller and being set back partly within the main roof and clad in matching roof tiles, it would not appear unduly dominant or visually intrusive in the wider area. Nor would the cumulative impact of the two rear dormers be such as to overwhelm the rear roofslopes.

Overall, the proposal would not harm the character or appearance of the host dwelling or surrounding area. It would comply with Policies DH1, DH3 and DH(a) and (h) of the Royal Greenwich Local Plan: [name] (2014) and Policies D3 and HC1 of The London Plan (2021) which seek a design led, high quality approach that optimises the capacity of sites whilst ensuring that it is compatible with the site context, that positively responds to local distinctiveness and roof extensions that respect the scale and character of the host building and surrounding area and which preserve or enhance the character or appearance of the conservation area and conserve the significance of heritage assets.

Regard has been had to the duty under S72 of the Planning (Listed Buildings and [name]) Act; I find that there would be no harm to the character or appearance the Westcombe Park Conservation Area. In addition, given the separation distances and that the proposed dormers are to the rear of the host building, there would be no effect on nearby non designated heritage assets. The proposal would therefore also satisfy the policies of the Framework which seek to ensure that heritage assets are conserved in a manner appropriate to their significance.

I have considered the conditions suggested by the Council and agree that these should include one to relate to the approved plans in the interest of clarity and proper planning and one to require matching materials in the interest of the appearance of the host building and visual amenity of the wider area.

It is therefore concluded that the appeal should be allowed and planning permission granted.