Appeal 3350437

The appeal is dismissed.

A revised version of the National Planning Policy Framework (the Framework) was published on 12 December 2024. The content of the revised Framework has been considered but in light of the facts in this case it does not alter my conclusion.

The main issue is the effect of the proposed development on the character and appearance of the main dwelling and whether it would preserve or enhance the character or appearance of the Hatcham Conservation Area (HCA).

The appeal relates to a two storey, brick built, mid-terrace dwelling house that is located in a predominantly residential area within the HCA. The northern side of [address] comprises similar terrace housing, of uniformed character, and with a noticeable degree of symmetry to the rear. Indeed, all of the residential terrace properties in this row have symmetrical adjoining two storey pitched roof outriggers.

The terms of Section 72 of the Planning (Listed Buildings and Conservation Areas) Act 1990 require me to pay special attention to the desirability of preserving or enhancing the character or appearance of conservation areas. I have been provided with limited information on the HCA as a whole and its significance. However, based on my site observations, I consider its significance, insofar as this appeal is concerned, to derive from the regular layout and appearance of its rows of historic terraced properties.

The proposed flat roof rear dormer would be of a substantial size and scale. It would only be set back approximately 0.23 metres from the eaves level of the rear outrigger and would occupy a vast proportion of its roof plane. It would also be built up to exceed the height of the rear outrigger’s roof ridge. Although it would not be ‘L’ shaped, these factors in combination with its bulky rigid box shaped appearance would result in the introduction of a dominant, top heavy, jarring feature that would have an awkward and unsympathetic relationship with the original dwelling and detract from the form and symmetry with the adjoining outrigger. As a result, it would also cause harm to the significance of the HCA

This impact would be compounded by the use of the synthetic slate materials. These would generally have a larger tile and a smoother texture and appearance than the outriggers existing slate roof tiles, thereby drawing the eye, and further accentuating its visual prominence, particularly in the context of the untouched roof forms of adjacent neighbouring dwellings.

Whilst it would not be visible from the front of the site or from the public realm, its discordant effect would be readily apparent from the windows and back gardens of neighbouring properties within the terrace and the care home to the rear. A suitably worded planning condition to ensure that the proposal’s roof tiles match the existing natural slates on the property would not negate or overcome all of the harm that I have identified.

I consider the harm that would be caused to the significance of the HCA would be ‘less than substantial’ within the meaning of the Framework. Paragraphs 212 and 213 of the Framework explain that great weight should be given to the conservation of a designated heritage asset, and that any harm requires clear and convincing justification. Paragraph 215 of the Framework goes on to state that where a proposal would lead to less than substantial harm to the significance of such an asset that this harm should be weighed against the proposal’s public benefits.

The provision of additional internal living space to meet the needs of the household is a personal rather than a public benefit. Given my reasoning above, I am also unable to find that the financial investment would result in improvements to the building. Furthermore, there is no evidence to demonstrate that the proposal is the only way to secure the retention of a young family in the area or ensure the long-term use of the building. With the above in mind, I therefore find that any limited public benefits involved do not outweigh the harm that would be caused to the significance of the HCA.

The proposed development would thereby cause unacceptable harm to the character and appearance of the main dwelling and would not preserve or enhance the character or appearance of the HCA. As such, there would be conflict with Policies 15 and 16 of the Lewisham Core Strategy Development Plan Document 2011, Policies 30, 31 and 36 of the Lewisham Development Management Local Plan 2014 and Policy HC1 of the London Plan 2021. These seek, amongst other matters, to ensure that development is sympathetic to the host dwelling and preserves or enhances the character and appearance of the conservation area.

In addition, conflict would arise with the design advice contained within the Council’s Alterations and Extensions Supplementary Planning Document 2019. The proposal would also fail to accord with the heritage objectives of the Framework, specifically in Section 16.

Several planning applications have been referred to me. However, none of these examples are for rear dormer extensions within a two storey symmetrical outrigger. Accordingly, their circumstances, and those of the existing ground floor extensions on [address] are not directly comparable to those which apply in this appeal.

For the reasons given above, having taken account of the development plan as a whole, along with all other relevant material considerations, the appeal should therefore be dismissed.