Appeal 3323884

The appeal is dismissed.

The main issue is the effect of the variations to materials and design of the dormer roof extensions upon the character and appearance of the existing building and greater locality, with special regard to the [address] Conservation Area (CA).

Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (PLBCA), in respect of development affecting conservation areas, states that special attention shall be paid to the desirability of preserving or enhancing the character and/or appearance of the area.

In undertaking extensions and alterations to existing buildings, the London Borough of Richmond Upon Thames Local Plan 2018 (LP) Policy LP1 lists a Appeal Decision: APP/L5810/D/23/3323884 number of design principles in order to ensure development respects, contributes to and enhances the local environment and character, such as consideration around compatibility with existing character; development patterns, views, local grain, scale; height, layout, siting, heritage assets and natural features, amongst others. LP Policy LP3 is related to heritage assets and seeks to conserve and enhance heritage assets, with development within CAs required to preserve and where possible enhance the character or appearance of the CA.

These policies are supported by the [name] and External Alterations Supplementary Planning Document (SPD) which contains further explanations and guidance with regards to extensions to existing properties. With regards to extensions the SPD seeks that the overall shape, size and position of extensions should not dominate the existing house and should harmonise with the original appearance. There is also the emphasis on protecting key spaces and gaps, and ensuring subservience.

The appeal site is located along [address], where the [name] states that the significance of the area derives from the Edwardian expansion which together with surrounding streets saw a large development of semi-detached properties. Each of the pairs of dwellings has similar designs with an arts and crafts influenced material palette, similar size, scale, and placement which creates a homogenous character with a formal picturesque Edwardian townscape that has a tranquil and suburban feeling and experience. Key strengths of the areas are highlighted in the [name] as houses with similar type and similar scale presenting a coherent appearance, wide avenues lined by trees, and abundant foliage in gardens, amongst others. Buildings are two storeys and contain red clay roof tiles, some with decorative ridge tiles, large chimney stacks, pitched roof forms with two storey projecting square bay windows with mock timber framing and a gabled roof. Dwellings are relatively modest in size and are positioned so that gaps exist between dwellings, particularly at first floor level, where there are glimpses to the tops of trees in rear gardens. [address], there is an emphasis on vegetation with street trees which along with front gardens reinforces a leafy and spacious quality and character to the CA.

Many of the dwellings along [address], and to the rear of dwellings on surrounding streets have large roof extensions, most of which are confined to the rear roof slope of the dwelling. Materials follow the characteristics of the host dwelling and seek to blend in with the design, scale and form of the existing dwellings.

The appeal building is one of the original characteristic dwellings which make up the CA and reflects the origins of the development of this area. The building is one half of a pair of semi-detached dwellings, two storeys with pitched roof and two storey projecting bay window with gabled roof above. The existing planning permission allows a dormer roof extension to the existing dwelling that is clad in tiles which match the appearance of the existing roof.

I can appreciate comments from the appellant with regards to there being different philosophies of design that can be applied to existing buildings, such as the proposal which seeks to apply a more ‘honest approach’ in that the alteration seeks to be deliberately modern which is sometimes utilised to alleviate concerns regarding pastiche and showing the evolution of Appeal Decision: APP/L5810/D/23/3323884 development over time. I also do not dispute that zinc is a high quality material and has been applied to historic assets, such as in place of lead or for the use of dormer cheeks and roofing.

In this particular location it was evident from my site visit and from surrounding dwellings, that the approach that has been followed in this particular area is that dormer roof extensions retain similar cladding materials as the host dwelling with the overall aim for the dormer extension to blend in with the existing building and give it a form a subservience. [name] agree that the proposed alterations to the approved scheme would present a high quality and honest appearance, the alterations would not be compatible with the host building and surrounding locality which seeks that extensions blend in, rather than to stand out with alternative design approaches that seek to highlight alterations. Whilst zinc is a high quality product, the large expanse of the material together with the large areas of glazing would be at odds with the materials and designs of dormer roof extensions surrounding and would look awkward and incongruous in this context.

I can appreciate that there are examples of zinc1 being used within the surrounding area, however the examples given are located to the side roof plane and are limited to side cheeks of small dormer windows and not to the extent of what is proposed in this scheme.

Taking the above into account, the proposal would not be a sympathetic alteration to the existing dwelling and would be harmful to the architectural authenticity and integrity of the existing building and surrounding area as a result of its use of materials. Consequently, the proposal would not preserve or enhance the significance of the CA and would cause ‘less than substantial harm’ to the CA. The proposed alterations to the approved scheme would be contrary to LP Policy LP1 and LP3 as discussed previously.

Whilst serious, it is considered that the proposal would cause ‘less than substantial’ harm to the character and appearance of the CA. Paragraph 202 of the Framework requires that, where a proposal would lead to less than substantial harm, the harm should be weighed against the public benefits of the proposal. The appellant has not described any benefits to the scheme, however the alterations would provide some short term employment opportunities. The benefits would not be dissimilar to those provided under the approved scheme, and therefore carry limited weight.

That said, I therefore find that the public benefits would not outweigh the harm to the CA. Each of the proposals would therefore conflict with the Framework, which directs, at paragraph 199, ‘that great weight should be given to the asset’s conservation ... irrespective of whether any potential harm amounts to substantial harm, total loss or less than substantial harm to their significance’.

In conclusion on this matter, I consider that each of the proposed alterations would cause less than substantial harm to the significance of the CA. It has not been shown that public benefits would outweigh this harm and so the proposal would conflict with the development plan and the Framework.

For the reasons given above, I conclude that the appeal should be dismissed. 1 No.s 33, 35, and 57 East Sheen Appeal Decision: APP/L5810/D/23/3323884