Appeal 3285285

The appeal is dismissed.

In its decision the Council sets out that it is the proposed rear dormer that it objects to. Consequently, whilst I have considered the impact of the scheme as a whole, I have focused on that aspect of it in my decision.

The main issue is the effect of the proposal on the character and appearance of the host property, and whether it would preserve or enhance the character or appearance of the Harpenden Conservation Area.

Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 sets out in respect of development affecting conservation areas, that special attention shall be paid to the desirability of preserving or enhancing their character or appearance. As Policy 85 of the City and District of St Albans District Local Plan Review 1994 (‘LP’) requires development in conservation areas to enhance or preserve their appearance, it reflects that statutory test.

Amongst other things, LP Policy 72 sets out that extensions shall be compatible with the original building with regard to matters including roof form, particularly in conservation areas.

The appeal site lies just within the Harpenden Conservation Area (‘HCA’). Here the dwellings on Park Mount are two storeys high, and typically sited close to the highway. In streetscene views they are mostly finished in red or buff masonry, have simple gabled roofs, and often display architectural detailing typical of their era, such as ornate brickwork, highlighted cills and lintels, and bay windows. To the rear, I observed that many nearby dwellings on this part of Park Mount have been extended or altered, and that they therefore have a less cohesive appearance.

Outside of the HCA on Park Mount to the south-west of the site, the urban grain changes markedly, with single and two storey dwellings set further back from the road, and which are of varied form and design, some with fairly prominent dormer windows.

The host is a detached two storey dwelling, with a plain gabled roof, a bay window and some modest architectural detailing on its front face, and a simpler rear elevation. Although unremarkable in its own right, the principal parties set out that it is a locally listed building, and on the basis of the limited available evidence, I agree that it is a heritage asset as defined by the National Planning Policy Framework 2021 (‘Framework’). Given that the building’s form, siting and design include locally distinctive characteristics typical of this part of the HCA, it also contributes to the significance of that designated heritage asset.

In its rearward location, the proposed dormer would have a modest impact on the streetscene, limited primarily to glimpses approaching along Park Mount from the south-west, where it would be partially obscured behind the retained chimney and the proposed side and rear extension.

The dormer’s materials and the proportions of its windows would respect those in the host property. However, although set in from the roof edges, viewed from the rear, given its substantial size and width, and the proportion of the roof that it would occupy, it would dominate the host property. Additionally, viewed together with the other proposed extensions, it would result in a complex roof form, which would detract from the host’s simple rooflines; and it would result in a large expanse of flat roof, which would be at odds with the host’s sloping roofs.

[name] 1 of their Design and [name] the appellants point to dormer windows elsewhere along Park Mount. However, many of those are outside of the HCA where I have found that the urban grain is very different; and those within it on this side of Park Mount at Nos 3 and 15 are not visible in the streetscene, and according to the Council, are smaller than this one; and I have few details of the approved rear dormer on the opposite side of the road at No 4.

Although only partially visible in the streetscene, the harm that this large dormer would cause to the host would be clearly visible from nearby properties, including some on Park Hill. In harming this building which displays characteristic features of this part of the HCA, the scheme would fail to preserve or enhance its character and appearance as a whole.

For the above reasons, the scheme would conflict with [name] 85 and 72, along with the more general stance on achieving an adequately high design standard in LP Policy 69. As the architectural interest of this locally listed building would be harmed, the scheme would also conflict with the broad thrust of LP Policy 87.

Although the energy efficiency of the dwelling may be enhanced, this scheme is not the only way in which that could be achieved. In its favour, the proposal would however result in additional accommodation for the current, and any future, occupants.

Summing up, the scheme would harm the design of the host property, and in so doing it would fail to preserve or enhance the character or appearance of the HCA. In accordance with the Framework, that is a matter to which I attribute great weight. However, as the harm would be ‘less than substantial’, I am required to weigh it against the public benefits of the proposal.

In this case, the harm that the scheme would cause to the HCA would not be outweighed by the very modest public benefit of providing additional housing accommodation. Consequently, as well as conflicting with the development plan, the scheme would conflict with the Framework.

For those reasons, and having regard to all other matters raised, the appeal is dismissed.