Appeal 6001203

The appeal is dismissed.

Since the determination of the application the subject of this appeal, the Council has adopted the [site address] Local Plan ‘the best for our borough’ 2024 to 2039 (7 October 2025) (the Local Plan). This supersedes the previous London Borough of [site address] Local Plan (July 2018). The main parties have had the opportunity to comment upon the implications of the adoption of the Local Plan.

The main issue is the effect of the proposal on the character and appearance of the host property and the St Matthias Conservation Area (the SMCA).

Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (the Act) requires that with respect to development affecting buildings or other land in a conservation area, ‘special attention shall be paid to the desirability of preserving or enhancing the character or appearance of that area.’

The appeal property lies within the SMCA. The character of the conservation area stems from the development of this part of Richmond in the mid to late 19 th century when the arrival of the railway led to substantial development of new streets and high-class villas on the slopes of the hill. Today, the conservation area is characterised by a mix of mid to late Victorian building styles and forms which include many substantial houses and large mews properties.

The appeal property is a large Victorian-era semi-detached three-storey dwelling with the second-floor accommodation contained within a pitched roof. It forms part of a long row of similarly designed pairs of houses which front the southwest side of [address]. The dwellings are sited close to the road, and they have a consistent front building line with frontage enclosure comprising low walls or fences. As such, the properties comprise a visually prominent feature within the street scene.

In recognition of their attractive and distinctive appearance, these houses are designated as Buildings of [name] (BTMs) by the Council. They have a distinctive brick-walled and slated pitched roof design and a regular pattern of window glazing detail, proportioning and positioning. They all incorporate similar attractive architectural features including window headers and corbelling, corner quoins and window cills, a decorative motif and feature band at roof level and brick chimneys with multiple pots. There is also a strong sense of visual symmetry between the pairs of properties having regard to the front and rear gable-ended roof form and the design and positioning of fenestration and architectural detailing.

The appeal property and the adjacent house at No.27 are the only buildings within the group that are three-storey. Although higher than the others within the group, they nonetheless exhibit the same aforesaid architectural detailing. The upper floor accommodation within the pitched roof space is served by front and rear windows, including a front centrally located feature window instead of a wall motif, and side-facing roof lights. As such, the roof form is in keeping with the pitched roofs of the other houses within this group of BTMs, and this higher pair of houses is consistent with the design aesthetics which characterise this row of buildings.

Moreover, whilst most of these houses, including the appeal property, have been altered and/or extended in a variety of ways since originally built, including the appeal site building, they have retained a strong sense of cohesiveness and harmony. [name] dwellings comprise an attractive feature within the townscape, making a strong positive contribution to the character and appearance of this part of the SMCA.

Many of the houses within this group of BTMs have been extended to the rear, including at upper floor level. This includes a pitched roof 2-storey addition to the rear of the adjacent property at No.27. As such, there is no objection in principle to an upper floor addition to the rear of the appeal property above the existing ground floor rear projection, subject to an appropriate design.

The other rear extensions include a mix of heights, depths and roof forms, but there is no cogent evidence before me that any of the first-floor additions are flat-roofed. Moreover, whilst the first-floor projection to the rear of No.27 extends as far as the rear of the site, it remains subservient in scale to the main building due to its cat-slide roof form which has the effect of significantly reducing its bulk, and also allowing the original building design at roof level to continue to be fully appreciated.

In contrast, the appeal scheme would result in a full-width and full-depth flat-roofed 2-storey addition to the rear of the building. This would comprise a notably larger and more bulky addition to the property than that which exists to the rear of No.27. Moreover, the perceived height of the addition would be increased by the proposed use of the whole of the flat roof as an open terrace, such that the proposed terrace level side parapet walls and glazed screens would extend above the eaves height of the original dwelling roof.

The result would be an unduly large and voluminous addition which would appear visually over-dominant and incongruous in relation to the host property and the adjacent rear first floor addition at No.27. It would harmfully impact upon the symmetry of the rear elevation, which is a key feature of the original building. This erosion of symmetry would be further compounded by the proposed replacement of the upper floor rear window with a door to access the terrace.

The existing property is characterised by modestly sized multi-paned windows which are key features within this row of BTMs. Although the appeal property includes significantly larger window and door openings on the rear elevation of the existing 2-storey addition, they remain domestic in scale and are broken up by many smaller individual panes. As such, they are consistent with the original building fenestration.

The proposed fenestration on the rear wall of the existing 2-storey extension would be notably more contemporary in design and would comprise a significantly different design of glazing panels which would have large, tall, rectangular-shaped glazing units which would not respect the original window design. Although incorporating a brick band midway up, the proposed area of glazing would be considerably larger than that which prevails within this group of houses, and it would occupy a disproportionately large area of the rear wall of the building, so that it would comprise a visually over-dominant incongruous feature within the building.

This effect would be exacerbated by the proposed similarly glazed and large ground floor side elevation and first floor rear elevation French door openings in the proposed rear extension. The result would be a preponderance of discordant more contemporary designed glazing which would take up a disproportionately large part of the building walls within which it is set. This would serve to emphasise the unduly large and discordant nature of the proposal as well as undermining the original character and appearance of the BTM.

The dissonant effect of the proposed glazing would be further compounded by the replacement of the rear elevation second floor window with a roof level door to the new balcony which would appear discordant immediately adjacent to the upper floor rear elevation window of No.27.

The appellant has drawn my attention to approved additions to the rear of Nos.13 and [address] which contain large single glazed glass panels. However, based on the information before me, these schemes are not directly comparable with the proposal before me in respect of the extension design, size and relationship to its host property. As such, they do not justify allowing the appeal scheme glazing, which I must determine based on the merits of the scheme before me.

The proposed side dormer would comprise a notably larger and more visually prominent feature within the roof slope compared to the existing small roof lights. Moreover, the roof slope would appear unduly cluttered because of the dormer, which would rise from the eaves, together with the proposed 3 surrounding roof lights.

When viewed from the public realm of the street, the dormer would appear as an unduly bulky side addition to the roof due to its height, depth and scale. It would unbalance the existing symmetry of the front elevation of the pair of houses and, notwithstanding that there are dormers elsewhere on the opposite side of the road, it would introduce an alien roof feature within the row of BTMs, where the original building side roof slopes remain intact and where side dormers do not feature. As such, the proposed dormer would comprise an unsympathetic addition to the property which would appear incongruous in the street scene.

Having regard to the above, the proposed rear extension and terrace, floor to ceiling height glazing and dormer window addition would harmfully undermine the architectural integrity of the BTM comprising 25 and [address]. This would be harmful to the character and appearance of the BTM and this part of the SMCA. This is notwithstanding that some elements of the scheme would not be visible from the public realm of the street or from neighbouring properties.

The statutory duty in Section 72 of the Planning (Listed Buildings and Conservation Areas) Act 1990 is a matter of considerable importance and weight. In terms of the advice in paragraph 215 of the National Planning Policy Framework 2024 (the Framework), the harm to the SMCA would be to the lower end of ‘less than substantial’ given the relatively modest scale of the scheme which relates to extensions and alterations to a single dwelling within the wider conservation area and the limited wider visibility of much of the scheme.

Consequently, the Framework sets out the need to address the ‘less than substantial harm’ in a balanced manner against the public benefits associated with the proposal. In doing so, however, paragraph 212 of the Framework sets out that when considering the impact of a proposed development on the significance of a designated heritage asset, great weight should be given to the asset’s conservation irrespective of whether potential harm amounts to substantial harm, total loss or less than substantial harm to its significance.

In this instance, whilst the proposal would improve the living conditions of the occupiers, this is not a public benefit, and no public benefits have been put forward in respect of the development to weigh against this less than substantial harm.

For the above reasons, I therefore conclude that the appeal proposal would cause significant harm to the character and appearance of the host property and the SMCA. It would therefore be contrary to Local Plan Policies 28, 29 and 30. Collectively and amongst other things, these policies seek to ensure that new developments, including extensions, are of a high architectural and urban design quality that responds positively to local character, and that they preserve and, where possible, enhance the character or the appearance of the conservation area and the character of non-designated heritage assets, including Buildings of [name].

For similar reasons, the proposal would also be contrary to Chapter 16 of the Framework in respect of the conservation and enhancement of the historic environment.

The proposal would conflict with the development plan taken as a whole, and there are no material considerations, including the Framework, that indicate that a decision should be made other than in accordance with the development plan.

Therefore, for the reasons given above, I conclude that the appeal should be dismissed.