Appeal 3285341

The appeal is dismissed.

I have added the replacement garage to the description of the proposal as it was not included in the description entered on the application form.

An application for costs was made by [name] against Swindon Borough Council. This application is the subject of a separate decision.

The main issues are the effect of the proposal upon a) the character and appearance of the existing dwelling and the area, and b) the living conditions of the occupiers of the neighbouring dwelling, No. 38 The Knoll.

The existing dwelling stands at one end of an elevated private road that runs parallel to [site address] , above a prominent stone retaining wall. It marks the southern end of a row of similar semi-detached pairs of generously proportioned early 20th century dwellings, with prominent two storey bays, hipped roofs and side chimneys. The dwellings are of architectural merit and are a significant contributor to the character and appearance of the area.

The side facing roof of the existing dwelling is highly prominent to view from the lower level of [site address] , and, along with the corresponding openings below, largely appears as it did when it was originally constructed. From this perspective the dwelling’s decorative ridge tiles, the timber brackets that support the front gable and the detail of the stone bay can all be readily appreciated.

The basic box like form of the proposed dormer would be in stark contrast to these existing details. It would be prominently positioned to straddle the rear hip, to extend from the rear across the dwelling’s side roof. It would appear wholly at odds with the form of the original dwelling. Rather than appearing as a well conceived contemporary addition with a clear additive form, it would have an awkward and rather clumsy relationship with the form of the existing roof, and would significantly detract from the largely unaltered and well detailed appearance of the existing dwelling. Owing to its elevated and prominent position, its harmful appearance would be easily seen from [site address] , where it would erode the positive contribution that the building makes to the character and appearance of the area.

I note that there are other examples of dormer extensions to properties along The Knoll. However, I could see none that were as prominent as the proposal before me.

I am mindful of the potential for the appellant to carry out similar development permitted by the General Permitted Development Order1. In this respect I am aware of the appellant’s submission of an application for a lawful development certificate that includes a substantial extension to the roof. This has not been determined and therefore the weight I give to this as a fallback position is limited. Notwithstanding this however, it does show an extension that would see the hip replaced with a straight gable. Although different to the strong repetitive pattern of hipped roofs along the row of houses, the formation of a full gable would allow the dormer to be contained more neatly and discreetly on the rear roof slope and is therefore likely to be less harmful than the dormer proposal subject of this appeal.

In a simpler and better defined manner, other elements of the proposal would be added to the rear elevation of the building or would be detached and would have a much more modest impact. Where it would adjoin the side boundary the single storey rear extension would be the same length as the existing extension and the extension to the rear of the neighbouring dwelling. Further into the site the extension would step out further into the garden, but with a slightly different material palette that would break its mass.

A further element would project out to the side, beyond the side wall of the existing dwelling. This part would be set at a lower level, which would follow the slope of the site and also give it a further additive form. It would not appear as an intrinsic part of the rear extension. Thus, although the maximum dimensions would constitute a substantial extension and would be beyond those suggested by the Council’s guidance2, the mass of the ground floor additions would be successfully managed by their arrangement into these separate components. 1 The Town and Country Planning (General Permitted Development) (England) Order 2015 2 [name] & Alterations Supplementary Planning Document 2011

The replacement garage would be set further into the site than the existing garage. It would be set down to follow the slope of the site and would relate well to the other extensions through the use of a similar material palette.

The proposal also includes a two storey element that would accommodate a new first floor bathroom. This would have a flat roof, which would allow it to sit neatly underneath the existing eaves line and thus be distinct from the existing dwelling. It would also enable it to relate well to the simple contemporary forms of the ground floor extension.

I accept that the materials proposed would be entirely different to the traditional materials used in the row of houses. However, the garage and the other rear extensions would be set well back. They would be largely unseen from [site address] . Where viewed from the end of the Knoll the various elements and overall material palette would appear well considered. The Council refers to the cladding material of the two storey part. Whilst this would be the same as the material for the dormer, which I have found would not be acceptable due to its prominent position and relationship with the existing roof, I am satisfied that it would be a modern high quality material that would work well with the materials proposed for the ground floor elements. Each part of the rear extension and the garage would have a simple additive form that would be distinct from the existing dwelling and would allow its form, scale and materials to remain the dominant street facing component.

In summary, the proposed dormer would harm the character and appearance of the existing dwelling and the area. It would be contrary to Policy DE1 of the Swindon Borough Local Plan 2026 (LP) and the [name] & Alterations Supplementary Planning Document 2011 (SPD), insofar as they seek to ensure that development proposals are designed to a high quality with regard to existing context and character, and recognise that box dormers should avoid conflict with existing changes in roof shape.

The proposed two storey extension would extend out to the rear alongside the boundary with the neighbour, No. 38 The Knoll. Owing to an existing single storey extension it would have no significant impact on the ground floor of this neighbouring dwelling or the ability to enjoy its existing garden.

However, the extension would be close to a first floor window at the rear of the neighbouring property. Assuming that the neighbouring dwelling has a layout that mirrors the appeal property, and taking into account physical factors such as the presence of obscured glazing and an outlet from an extractor fan, the closest window would appear to serve a bathroom. The extension would impinge on the 45 degree line when measured from this window, however as a bathroom it would not be considered a habitable room and the SPD makes it clear that this test would not be relevant.

The window beyond is likely to serve a bedroom, and thus a room that is regarded as habitable for the purposes of the SPD. The additional details submitted as part of the appeal make it clear that the extension would not impinge on a 45 degree line drawn from the centre of the bedroom window. Even if I take into account its position to the south of the neighbour, I am satisfied that the extension would be far enough away that its impact on the outlook and level of light reaching this window would be modest. It would not be sufficient to harm the living conditions of the occupiers of this dwelling.

In summary, the proposed two storey extension would not harm the living conditions of the occupiers of the neighbouring dwelling. It would accord with Policy DE1 of the LP and the SPD insofar as they seek to ensure that development proposals are designed to a high quality with regard to light and outlook impacts.

I have been provided with details of the Council’s recent decision3 on a prior approval notification for a 6 metre long rear extension. This matter has no bearing on my consideration of the proposed dormer extension.

In conclusion, although I have found that the proposal would not harm the living conditions of the occupiers of the neighbouring dwelling this is a neutral matter that cannot outweigh the harm I have found regarding the impact of the proposed dormer. Therefore, for the reasons above, the appeal should be dismissed.