Appeal 3307045

The appeal is dismissed.

The main issue is the effect of the proposal on the character and appearance of the host dwelling and the Southgate Green Conservation Area.

No. [site address] (No.9) is a detached two-storey 1950s dwelling located within the Southgate Green Conservation Area (SGCA). Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (the Act) requires that special attention be paid to the desirability of preserving or enhancing the character or appearance of conservation areas. No.9 is not listed, or locally listed and the Council’s Heritage and Conservation Advisor does not identify No.9 as a non-designated heritage asset. Accordingly, I have not considered it as such.

SGCA is centred on The Green with three main roads, including [address], radiating from it, each with its own individual character. The Southgate Green Conservation Area [name] (2015) (CACA) explains that the significance of the SGCA is derived from its architectural and historic interest. This includes its considerable time depth in buildings which range from the late [postcode] to the late [postcode] which, as described in the CACA, ‘vividly illustrates the village’s development from an isolated woodland hamlet to the centre of a metropolitan suburb.’

No.9 is identified in the CACA (Figure 8) as a building making a positive contribution to the area. The appellant’s case is that No.9 makes a neutral or slight negative contribution to the SGCA with reference to a ‘checklist’ of twelve questions set out in Table 1 of Historic England’s (HE) Conservation Area Appraisal, Designation and [name] 1 (2019). The HE checklist is designed to help with the process of appraising a Conservation Area, where a positive response to one or more criteria in the checklist may indicate a particular building makes a positive contribution.

It is recognised that No.9 does not meet many of the checklist criteria. However, as shown on the OS map regression included with the Heritage Appeal Statement, it does clearly illustrate a phase of the development of Southgate Green as an identifiable infill between two earlier, and grander, dwellings dating from the first part of the [postcode] . Whilst the key phases of the development of Southgate Green was the [postcode] and [postcode] , No.9 as a 1950s infill development nonetheless forms an important part of the time depth of buildings which contributes to the significance of the SGCA. It further reflects the traditional functional character of the area.

The CACA describes [address] as more suburban (than The Green) in nature, with houses more prominent in the streetscape. The appellant alleges that No.9 has a limited presence in key views due to its set back and intervening built form and tree cover. From my site visit, I found this not to be the case and despite the mature tree in the grass verge to the front of No.9, it is very prominent in the streetscene and is recognisably of a different age and design than its neighbours. Visually and historically, No.9 contributes to the time depth of buildings in the SGCA and consequently, I concur that, as identified in the CACA, No.9 is a building that makes a positive contribution.

No.9 has a gabled, part catslide roof above an arched porch, with two dormer windows in the front roofslope. The proposal is to raise the eaves of the roof to create a true first floor and change the gable to a hipped roof form. The overall height of the roof would not be significantly increased and I accept that the roof form would not markedly increase the massing of the dwelling, when viewed directly from [address]. The design of the front elevation, with three symmetrical bays, a central projecting gable and prominent chimney stacks, reflects the design of the neighbouring dwelling at No.[address]. Whilst the design (and use of materials) has clearly been informed by the neighbouring context, the result of the change to the roof form is to entirely lose the 1950s design and form. It would therefore cause harm to the character of the host dwelling and fail to preserve the character and appearance of the SGCA.

I am not persuaded, as alleged by the Council, that the proposed crown or hipped roof itself would fail to give a legible roof form or give rise to an alien three-dimensional form that is not observed elsewhere in the SGCA. The hipped profile of the proposed roof is not unusual and would appear a simple and legible form when viewed from [address]. Further, I have had regard to the Inspector’s decision in respect of No.[address] (APP/Q5300/W/16/3165937) and I similarly observed on my site visit that there are other examples of hipped or crown roof forms in the SGCA, notably in this case next door at No.[address]. That said, although it is not proposed to demolish No.9, for the reasons given above the loss of the gabled, catslide roof would, to all intents and purposes, result in the loss of the 1950s design of the dwelling.

The existing plan form of No.9 is not particularly deep and to the rear it has an existing large two-storey flat roof extension across around half the width of the dwelling. A full width part single, part two-storey rear extension is proposed essentially forming an L-shape around this two-storey extension. The proposed extension would project between around 2.7m and 8m from the existing rear building line and would significantly increase the footprint of No.9. However, the footprint and rear building line would be comparable to those of the neighbouring dwellings at No.7 and No.[address] and would not appear a disproportionate or unsympathetic addition to the dwelling, or the plot, given the generous size of the garden.

Because of the siting of No.[address] (No.7) on a similar front building line and close to the boundary of No.9, the proposed rear extension would not be particularly discernible travelling south to north on [address], largely hidden by the massing of No.7. The existing narrow gable, plan form and part of the flat roof of the two-storey extension on the northern flank of No.9 is, however, visible in the streetscene because of separation distance from No.[address], which splays away slightly from its neighbour. Whilst visible, the depth of the proposed extension would again be comparable to the depth of plan of its neighbours and it would replace the somewhat visually incongruous flat roof extension. Further, as the massing of the extension would be to the rear, the spacing or visual gap between No.9 and No.7 and 11 would be largely unaltered and the plot would retain its characteristic verdant setting, with all trees (save an [name]) within the rear garden retained.

Although the proposed rear extension would not read as a subservient addition to No.9, I note that it is not a policy requirement of either Policy DMD6 or DMD11 of the Development Management Document (2014) (DMD) which together require development (including rear extensions) to be of a scale and form appropriate to the existing pattern of development and to have no visual impact.

Notwithstanding my conclusions in respect of the rear extension, the proposed roof form would cause harm to the appearance of the host dwelling, and would not preserve or enhance the character or appearance of the SGCA resulting in the loss of the 1950s design. It would therefore fail to comply with the statutory requirements of S72(1) of the Act. Paragraph 199 of the National Planning Policy Framework (the Framework) requires that great weight should be given to the conservation of a heritage asset. In this case, the harm to the significance of the SGCA would be less than substantial. Paragraph 202 of the Framework requires such harm to be weighed against any public benefits of the proposal. The appellant has not provided me with any public benefits to outweigh the less than substantial harm identified in this case.

Consequently, the proposal would conflict with the requirements of Core Strategy Policy CP30 and CP31, [name] DMD6, DMD8, DMD37 and DMD44, and London Plan (2021) Policies D3 and HC1. Together, these policies require development to preserve the significance of designated heritage assets and be a high quality design in relation to local character, scale, form and pattern of development.

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