Appeal 3297761

The appeal is dismissed.

The proposed floor plans provided ([name] 005 [name] and 006 [name]) indicate that both the ground floor and first floor side elevation would be located 1.0 metre from the side boundary with No [address]. The proposed rear elevation ([name] 008 [name]) also indicates this would be the case. However, the front and side elevations provided on [name] 007 [name] show a single storey element next to the boundary with No 16A. Furthermore, the proposed floor plans show a single first floor front elevation window on the extension to this side of the dwelling whereas the front elevation plan provided shows two windows. Given that I am dismissing the appeal, it has not been necessary to address the discrepancies between these plans any further.

The description of the proposal on the Council’s decision notice differs from that on the application form and includes ‘brick piers, walls and railings to highway’. It is clear from the third-party written representations made that the planning application was consulted upon on that basis. Therefore, I have also considered this element of the proposals within my assessment of the appeal.

The main issues are: (i) whether the proposal would preserve or enhance the character or appearance of the Chislehurst Conservation Area, including but not limited to the effect on protected trees; and (ii) the effect of the proposal on highway safety.

The London Borough of Bromley Supplementary Planning Guidance for Chislehurst Conservation Area ([name]) confirms that the CA comprises of a cluster of predominantly residential areas either on the perimeter of the central common or slightly beyond it. The CA has a wooded, semi-rural character with extensive coverage by mature trees, woodland and open grassed areas which extend into those parts of the CA developed with buildings. Residential development in the CA is predominantly characterised by spacious suburban development.

[address] forms a main route through the CA and the section of this road where the appeal site is located reflects the CA’s predominant wider character. Woodland sits on one side of the road and the other side consists of mainly large, detached dwellings in generous plots which often contain mature trees. Where front boundary treatments exist these mainly comprise of picket fencing and hedges which are low in height.

No [site address] is a detached two-storey dwelling situated on a corner plot. Its open front boundary and the generous spacing between the two-storey side elevations of the appeal dwelling and the boundaries of the site complement the CA’s spacious attributes. Amongst the planting on the site, there are some substantial mature trees covered by a Tree Preservation Order (TPO). These trees are situated close the boundary with [address] and are prominent in the street scene. The dwelling’s front elevation is well-balanced and its hipped roof, decorative eaves detailing, Georgian style window design, pinned back external shutters and external facing materials complement the similar aspects of design seen on the neighbouring dwelling at No [address].

As a result of the above factors, the dwelling sits comfortably within its spacious plot and together with the pleasing symmetry and characteristic detailing to its front elevation, the prominence of trees within the site and the openness of its frontage, the site makes a positive contribution to the character and appearance of the CA, adding to its significance.

Even though the extensions would be set back, their height and two-storey mass to either side of the front elevation would overwhelm the dwelling’s original form. The differing widths of the side extensions would also detract from the host dwelling’s symmetry. The floor plans indicate that the two-storey side elevations would sit only 1.0m from the respective side boundaries of the site. Without more generous side space, the considerable bulk of the extended dwelling would appear cramped within its plot. Consequently, the proposal would have a detrimental effect on the appearance of the host dwelling and would unacceptably erode the higher standards of separation which presently exist on the site.

Even if I consider the proposal on the basis of the front elevation drawing before me, which indicates a single storey element to the side of the extended dwelling next to the boundary with No 16A, the bulk of the first floor elements and their close proximity to the side boundaries of the site would still detract from the well-balanced design of the original building and would unacceptably erode the spacious qualities of the appeal site and the CA.

Furthermore, the Council’s Tree Officer has suggested that the proposal would present an unacceptable risk to a mature 20m tall Lime tree covered by a TPO which has significant public amenity value given its clear visibility from [address] and [address]. This is consistent with my own observations on site as it was clear that the proposed footprint of the rear part of the two-storey extension closest to the boundary with [address] would sit under the canopy of this substantial mature tree.

I have not been provided with a copy of the arboricultural surveys referred to in the appellant’s statement of case. In any case, there is no detailed evidence before me to dispute the Tree Officer’s concerns in respect of the impact of any piling foundations on the root system closest to the stem of the tree, the potential detrimental effects on surface water infiltration and gaseous exchange as a result of the further covering of the root protection area beyond areas of existing hardstanding, as well as the potential for future pressure from occupiers of the host dwelling to prune or remove the tree given the very close relationship between this tree and the extended dwelling. In the circumstances, I cannot be certain that the development would not compromise the health of or ultimately result in the loss of this important tree.

In addition, I acknowledge that the gaps between the metal railings within the front boundary proposals would facilitate views from the street into the site. Nevertheless, the boundary treatment would still have an enclosing impact on the frontage. Due to its height and composition, it would also have overly formal and imposing appearance compared with the overriding more simple and lower scale boundary treatments to this section of [address]. This would further compound the detrimental impact of the wider proposals on the spacious characteristics of the site and the CA.

The appellant suggests that there is other similar development in the area and has drawn my attention to extensions approved at No 3 Liskeard Close1. However, the design of that particular extension and its relationship with the appearance of its host dwelling and the wider street scene is not the same as the appeal proposal. Having assessed the appeal on its own merits taking into account its individual design and site-specific context, I am not persuaded that the example provided justifies the harm to the CA that would result from the appeal proposals.

Having regard to the requirements of the National Planning Policy Framework (the Framework), the proposals would result in less than substantial harm to the character and appearance of the CA. Paragraph 202 of the Framework states that where a development would lead to less than substantial harm to the significance of a designated heritage asset, this harm should be weighed against the public benefits of the proposal including, where appropriate, securing its optimum viable use.

The proposal would provide additional living space resulting in a private benefit for occupiers of the host dwelling. However, I find that there are no public benefits in this instance that outweigh the less than substantial harm that would be caused to the significance of the CA.

I conclude the development would result in significant harm to the character and appearance of the CA. In that regard it would conflict with the design, 1 [name]/21/04214/FULL6 conservation and tree protection requirements in Policies 6 ([name]), 8 ([name]), 37 (General Design of Development), 41 (Conservation Areas), 43 (Trees in Conservation Areas) and 73 (Development and Trees) of the London Borough of Bromley Local Plan (2019) (LP) and the Framework.

At the time of my visit, while only a snapshot of the traffic conditions in the area, vehicles regularly passed the site both in terms of those travelling in either direction along [address] as well as vehicles turning right onto [address] from the junction with [address]. A 30mph speed limit is in place in the vicinity of the site entrance.

The proposed brick piers and railings would extend further along the side boundary with [address] towards [address] than the existing close boarded fence. From what I saw on my site visit the solid elements of the boundary treatment, both in terms of their position along and extending away from this boundary, would have the potential to reduce visibility for drivers on [address] of oncoming traffic approaching from the right along [address] when compared with the existing situation.

The block plan before me states that the green dashed lane indicates ‘Visibility splay line as shown as requested by highways’. However, there are no detailed measurements on the block plan to demonstrate that the highway authority’s requested visibility sightline of 53.6m x 2.4m would be provided. Alternatively, there is no evidence before to suggest that actual recorded traffic speeds on [address] indicate that an alternative visibility sightline would be suitable. Therefore, I cannot be certain that the proposal would not unacceptably increase the risk of collision for drivers exiting [address] onto [address].

The appellant suggests that they would be willing to lower the height of the proposed boundary treatment. However, in the absence of a plan showing precise lower heights together with detailed visibility splay measurements I am not in a position to assess the overall relationship with highway safety.

In addition, the proposed gates would be located very close to the front boundary. This means that any vehicle entering the appeal site would not be able to pull clear of the highway until the gates were opened. More particularly, in instances where vehicles were to pull up to the gates before they were open, they would obstruct the pavement and overhang the carriageway. I agree with the Council that an electronic mechanism which guarantees gates would always be open to allow a vehicle to pull freely into the property on arrival would be difficult to monitor and enforce. Therefore, gates in this position would be likely to result in vehicles waiting on the highway and this would cause inconvenience for pedestrians and other road users, adding to the harm already identified.

I conclude, it has not been demonstrated that the development would not have an unacceptable impact on highway safety. In that regard it would conflict with the requirements to ensure road safety is not significantly adversely affected in Policy 32 ([name]) of the LP as well as the requirements at paragraph 111 of the Framework.

The Council’s handing of the planning application, including the time taken for determination and whether or not the Council indicated a favourable decision would be forthcoming, are not material to my independent assessment of the proposal against the relevant policies of the development plan and the Framework.

The proposal would not preserve the significance of the CA. Furthermore, it has not been demonstrated that the development would not have an unacceptable impact on highway safety. The proposal therefore conflicts with the development plan taken as a whole. There are no material considerations that indicate the decision should be made other than in accordance with the development plan. The appeal is therefore dismissed.