Appeal 6000526

The appeal is dismissed.

The site visit was undertaken by a representative of the Inspector whose recommendation is set out below and to which the Inspector has had regard before deciding the appeal.

The Council do not object to the rear single storey extension, porch, rear dormer window or hip to gable roof extension elements of the appeal scheme. These benefit from prior approval. My recommendation therefore focusses on the two-storey side infill extension and changes to the fenestration and material finish of the existing dwelling and, specifically, their effect on the character and appearance of the area.

The appeal property forms one of a pair of substantial semi-detached, two-storey dwellings located on an active main road. Both exhibit a traditional architectural style, characterised by two-storey gabled bay windows to the front, white fenestration, and decorative white detailing to the bays. The facades are finished in distinctive pebble-dash render, complemented by hipped roofs. The surrounding area is defined by properties of similar scale and design, sharing features such as bay windows, white fenestration, and textured finishes. The uniformity of appearance is reinforced by the limited extent of visible alterations, regular plot spacing and generous front gardens with off-street parking. Collectively, these elements contribute to a coherent and attractive streetscape that positively defines the character and appearance of the area.

The proposed two-storey side extension would maintain the existing separation to the boundary with Number [address]. It would not project laterally towards the neighbouring property, but rather, advance forward from the existing building line. Thereby preserving the established spatial relationship between the appeal site and adjoining neighbours. In addition, it would remain subordinate to the host dwelling, as the design incorporates a first-floor setback and a pitched roof set below the principal ridge, which would also represent a visual enhancement compared to the previously approved flat-roofed scheme under the prior approval. Furthermore, given the significant setback of the appeal building from the road frontage, the existing gap ensures that the size and scale of the side extension would not appear unduly prominent or visually incongruous.

That said, the use of anthracite grey aluminium windows together with a silicone render finish across the entire exterior would introduce a material palette wholly at odds with the established character of the host dwelling and its semi-detached counterpart. The prevailing use of white-framed windows and traditional pebble-dash render is a defining element of the architectural vernacular. These changes would result in a stark and incongruous appearance, disrupting the visual cohesion of the street scene and causing demonstrable harm to local distinctiveness.

The scheme therefore, taken as a whole, would be harmful to the character and appearance of the area. As such, it would be contrary to Policy D3 of The London Plan, the Spatial Development Strategy for [name] (2021), Policies CDH01 and CDH05 of the Barnet Local Plan 2021-2026 (2025) and guidance contained in Residential Design Guidance Supplementary Planning Document (2016). Amongst other things, these seek to ensure development uses suitable materials that respect and compliment the character of the existing building and setting.

The prior approval scheme is a fallback position. However, it did not involve alterations to the fenestration or external finishes and, as such, is not sufficiently comparable to the proposal before me, particularly in relation to the harm I have identified.

The replacement windows would be an other alteration for the purposes of the Town and County Planning (General Permitted Development) (England) Order 2015 (GPDO). Such would be permitted thereby provided, according to condition A.3 (a), materials are of a similar appearance to those used in the construction of the exterior of the existing dwelling. Grey aluminium is not similar in appearance to white UPVC. It is in fact more than materially different. Allowances under a different class of permitted development would not affect this finding. I am not minded to recommend allowing the appeal in this light.

For the reasons given above, the appeal proposals would conflict with the development plan and there are no sufficiently weighty material considerations to indicate a decision other than in accordance therewith. I therefore recommend that the appeal should be dismissed.

I have considered all the submitted evidence and my representative’s report and on that basis the appeal is dismissed.