Appeal 6005886

The appeal is dismissed.

The main issue is the effect of the proposal on the character and appearance of the dwelling, street scene and wider conservation area.

The appeal property comprises an end-terrace dwelling forming part of a terrace of interwar houses on [address] within the Watling Estate Conservation Area. Whilst the appeal property appears to be a later addition to the terrace, it is well executed with appropriate materials and detailing.

[address] is characterised by terraces arranged within a planned suburban street layout typical of the estate. The properties share a consistent building line and uniform scale, with simple elevations, regularly spaced apertures and pitched roofs creating a strong sense of rhythm. The houses are generally set behind modest front gardens / parking areas and many have defined boundary treatments.

These characteristics of the terrace row within which the appeal property sits are representative of the wider Watling Estate Conservation Area, which derives much of its significance from the coherence of its layout, the consistency of terrace housing and the uniformity of scale, materials and architectural form.

The appeal proposal seeks planning permission for a two-storey side extension and a first-floor addition over the current ground floor rear extension. The proposed side extension would extend the full depth of the house with a pronounced step out towards the boundary at the rear. The first-floor element fronting the road would be set back slightly from the front elevation with a small lean-to roof section bridging the gap between the ground floor front elevation and the slightly recessed first floor elevation.

The proposal appears to have evolved from consented scheme 25/2985/HSE. The principal differences being that the ground floor element fronting the street would be flush with the front elevation and feature a small lean-to roof to tie it into the first-floor structure, the side elevation to the rear would be extended further out towards the boundary and a new first floor bedroom is proposed above the existing ground floor extension.

Whilst the consented scheme is a material consideration to which I attribute weight, it nevertheless falls to me to consider the appeal scheme afresh against the Development Plan and to apply the statutory duty for Conservation Areas under Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (the Act).

The appeal property occupies a prominent end-of-terrace position within a row characterised by a consistent scale, spacing and architectural form. Whilst it already differs to some extent from the prevailing terrace composition as a later addition within the row, the increased width, depth and overall massing of the proposed extension would further erode this consistency and result in the dwelling appearing as a dominant and incongruous element which would disrupt the rhythm of the terrace.

This effect would be reinforced by the variation in depth between the ground and first floor, resulting in a visually fragmented appearance uncharacteristic of the Conservation Area. The ground-floor element projecting flush with the front elevation would form a prominent feature of the front elevation and would fail to achieve a suitably subordinate relationship with the host dwelling.

Whilst the appeal property appears to occupy a slightly wider plot than some others within the terrace, the character of [address] is derived primarily from the consistent scale, alignment and architectural form of the terrace. The maintenance of separation distances does not therefore outweigh the effect of the increased width, depth and overall massing of the proposal on the coherent appearance of the terrace.

Even taking account the siting of the substation which abuts the site boundary, the effect on the appearance of the terrace would be readily apparent from the street, thereby eroding its contribution to the character of the Conservation Area.

I have limited evidence before me regarding the circumstances in which the other cited examples of development within the Conservation Area were approved, or whether they are directly comparable to the appeal proposal. In any event, those examples do not in themselves justify the proposal before me.

For the reasons given above, I find that the proposal would fail to preserve the character and appearance of the Watling Estate Conservation Area.

Paragraph 212 of the National Planning Policy Framework (the Framework) advises that when considering the impact of development on the significance of designated heritage assets, great weight should be given to their conservation. Given the harm would arise from the overall massing of the proposed development and its effect on the appearance of the appeal property and the terrace and character of [address], I find the harm to be less than substantial in this instance but nevertheless of considerable importance and weight.

Under such circumstances, paragraph 215 of the Framework advises that this harm should be weighed against the public benefits of the proposal. The appellant is of the opinion that the proposal would be beneficial because it would adapt and improve the quality of the existing dwelling including through increasing the number of bedrooms to provide a family-sized dwelling, thereby making efficient and effective use of a dwelling plot within an established residential area.

Whilst the improvement to the housing stock would be a small public benefit, it would not be of sufficient magnitude to outweigh the harm to the CA, to which I afford great weight. The proposal would fail to preserve the character or appearance of the Conservation Area and would thus fail to satisfy the requirements of the Act.

As a result, the proposal would conflict with Policy D3 of the London Plan (2021) which requires proposals to respond to local character, Policy HC1 which seeks conservation of heritage significance, Policies CDH01, CDH05 and CDH08 of the Barnet Local Plan (2025) which seek high quality contextual design, subordinate residential extensions and preservation of Conservation Areas respectively, the Residential Design Guidance SPD (2016) which provides guidance on sympathetic extensions, the Watling Estate Conservation Area Character Appraisal (2007) which identifies coherence of terrace form as significant, and the Framework which seeks to conserve heritage assets.

For the reasons given above, and taking into account all other matters raised, I conclude that this appeal should be dismissed.