Appeal 3352915

The appeal is dismissed.

While the appellant has described the proposal as in the above heading, the Council has referred to it as the erection of a rear roof extension with a hip to gable conversion and three front roof windows to the house. From my inspection of the plans, I consider that the Council’s description more fully reflects the development sought. I have assessed the proposal on that basis.

On 12 December 2024, a revised National Planning Policy Framework (the Framework 2024) was published with an amendment issued on 7 February 2025. The Framework 2024, as amended, does not raise any new matters that are determinative to the outcome of this appeal.

The main issue is the effect of the proposed development on the character and appearance of the host building and the local area.

[name] is a short residential cul-de-sac of 2-storey semi-detached houses with hipped roofs. The dwellings along nearby streets, including [address] and [name] have similar characteristics with greater variation in roof forms.

The appeal property occupies a prominent position broadly facing the junction between [name] and [address]. Unlike its attached counterpart, No 10 has a 2-storey side extension with a hipped roof and a canopy above the main front entrance. As a result, the sense of balance and general symmetry between the dwellings within this pair has been disrupted. Similarly, the dwellings within other pairs along [name] no longer match due to various alterations that have taken place. Nevertheless, hipped roofs remain a prominent and a characteristic component of the host building and the street scene to which No 10 belongs.

The continuation of the main roof at the same height as the existing main ridgeline and the inclusion of a gabled end elevation, as proposed, would lead to an unacceptably dominant and discordant front elevation. When viewed from the road, the completed dwelling would be uneasy on the eye given the imbalance and contrast with the attached dwelling, which retains its original hipped roof form, as do other properties on [name]. There would also be an incongruous detail in which the hipped roof of the existing side extension would terminate below the apex of the new gable, thereby creating an awkward juxtaposition of roof lines. Consequently, the gabled roof and front elevation, as proposed, would be obtrusive and an unwelcome addition to the local area.

The Council’s Residential Extension Guidelines Supplementary Planning Document (SPD) notes that hip to gable alterations will normally be refused because they can unbalance the appearance of the house or the pair. The proposal before me is one such example. While the SPD does not provide a rigid set of rules to be slavishly applied, it nonetheless provides guidance that is relevant in this case.

I saw several properties within the local area in which the roof form of one dwelling within a pair differs to that of its attached counterpart including those to which the appellant has referred and provided photographs. To my mind, these changes serve to illustrate that even modest alterations at a high level on a building can have a significant effect on the character and appearance of the host property and its context. In some cases, the resultant disharmony between the appearance of the dwellings within a pair due to their contrasting roof shapes exemplifies the harm that I have identified. Therefore, these cases do not lend support to the appellant’s case. While gable ended properties are evident in the area surrounding the site it is within the context of [name] that the proposal would be primarily seen.

The Council appears to raise no objection to the new dormer, which is to be placed onto the extended rear roof slope and to the roof lights at the front of No 10. From the submitted evidence, I have no reason to reach a different conclusion on these aspects of the appeal scheme. However, from my inspection of the drawings, these elements of the proposal are not clearly severable from the new gabled end and front elevation, which are objectionable. Therefore, I have not issued a split decision that grants planning permission solely for them.

The appellant places some reliance on the changes that could be achieved to the appeal dwelling through the exercise of permitted development (PD) rights. Details are provided, which demonstrate that the new gable end could come forward with a small dormer placed on the rear roof slope. This option is an alternative to the proposal before me and it represents a realistic fall back for the appellant if the appeal were to be dismissed. Nevertheless, planning permission is sought for the development as a whole and I have assessed it on that basis. That assessment has taken into account all the submitted evidence including the Council’s policies and guidance, the Framework 2024 and local circumstances ‘on the ground’.

Having done so, I conclude on the main issue that the proposed development would cause significant harm to the character and appearance of the host building and the local area. It is therefore contrary to Policies CC1, CC2 and SC7 of the Hounslow Local Plan 2015-2030 and the Council’s SPD. These policies and guidance aim to ensure that development complements the original building, harmonises with adjoining properties and maintains the character of the street scene. It also conflicts with the Framework 2024, which states, amongst other things, that development should be sympathetic to local character and add to the overall qualities of the area.

Overall, the development sought conflicts with the development plan, when read as a whole. There are no material considerations, including the policies of the Framework 2024, which indicate that the decision should be taken other than in accordance with the development plan.

For the reasons set out above, and having regard to all other matters raised, I conclude that the appeal should be dismissed.