Appeal 3350539

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 front roof windows. 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.

At the site visit, I saw that there was a dormer extension on the rear roof slope of No 120 and a rooflight on the front roof slope, which are not shown on the plans. I note that the canopy above the front entrance is also omitted from the drawings of the appeal dwelling and that the chimneystacks, which form part of the proposal, were removed ahead of the application submission. For the avoidance of doubt, I have assessed the proposed development as it is shown on the submitted drawings because it was on that basis that planning permission was refused.

The appellant appears to indicate that the proposal could come forward through the exercise of permitted development (PD) rights. Within the context of an appeal under section 78 of the Act it is not within my remit to formally determine whether the proposed development requires planning permission. If the appellant wishes to ascertain whether the development sought would be lawful, they may make an application under section 191 or 192 of the Act.

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, the terrace to which it belongs and the local area.

The appeal property is a 2-storey end terrace house on a residential street that mainly comprises terraces and semi-detached houses of similar age and general style. I saw that some properties within the area of which the site forms part have been externally altered and extended at roof level including those examples to which the appellant has referred and provided photographs. As a result, there is some variety to the appearance of the existing built form in the local area.

Nevertheless, I observed that most buildings within the street scene to which the site belongs include hipped roofs, as do No 120 and its counterpart at the opposite end of the same terrace, which is [address]. Taken together with other features that are common to Nos 120 and 126 such as their 2-storey front bay and gable facing the road, the hipped roof of these properties positively contributes to the sense of balance and symmetry across the terrace, which is distinctive.

The hipped end to the main roof of No 120 is proposed to be altered to form a gable. The extended roof of No 120 would be visible from along [address] from where the entirety of the host terrace and the hipped ends of the terraces on either side would be seen. When viewed from the road, on either side of the site, the completed dwelling would noticeably contrast with No 126, which retains its original hipped roof form. In that context, the proposed gable would draw the eye as a prominent and discordant feature that would disrupt the broad symmetry and sense of balance to the wider terrace. As such, this element of the appeal scheme would obtrusive and an unwelcome addition to the local area.

The Council’s Residential Extension Guidelines Supplementary Planning Document (SPD) warns that hip to gable alterations will be refused because they can unbalance the appearance of the house or the terrace. 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.

At the rear, the new dormer would be a sizeable addition. It would extend across almost the full width of the enlarged rear roof with the top set just below the main ridgeline. Taken together with its flat roof, the dormer would appear as an overly large and bulky ‘box-like’ addition that would overwhelm the main rear roof. As such, it would be at odds with the advice within the Council’s SPD, which states that dormer extensions must be modest in size and should not dominate the roof. Furthermore, as the only example of such development within the same terrace, the new dormer would be incongruous.

[name] 126 does not include chimneystacks above eaves level, the proposal would rebalance the terrace in this limited respect. I note the external materials to be used would match those of the existing dwelling and agree that most of the new dormer would not be readily visible from the road. It would, however, be visible from the rears of properties on either side of the site.

I have also carefully considered the numerous cases to which the appellant has referred in which planning permission has been granted for extensions on properties elsewhere where reference has been made to the exercise of PD rights and/or an imbalance to the host terrace has resulted. From the summary details provided, it is unclear whether the circumstances of any of these examples are the same or very similar to those of the proposal. It is therefore difficult to draw direct parallels between these cases and the appeal scheme. Furthermore, none of the examples cited would be seen in the same context as the site. In any event, a key principle of the planning system is that each development should be assessed on its own merits, which I have done.

I acknowledge that residential extensions that could be or have been achieved under PD has been a relevant consideration in each of the cases identified by the appellant. Roof level additions, whether constructed through the exercise of PD rights or following the grant of planning permission, also form part of the character of the area of which they form part. To briefly reiterate, planning permission is sought for the development, as a whole. I have assessed it on that basis and taken into account all the submitted evidence.

On the main issue, I conclude that the proposed development would cause significant harm to the character and appearance of the host building, the wider terrace and the local area. It therefore conflicts with 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 is also contrary to the Framework 2024, which states that development should be sympathetic to local character and add to the overall qualities of the area.

That the proposal was amended during the application stage is noted, as is the [name] indication that a revised scheme would be recommended for approval. Once complete, the proposal would provide valuable additional living space for the appellant. It would also make good use of the roof space available within the property. However, these considerations do not outweigh the significant harm that I have identified in relation to the main issue.

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, including the absence of objections from others, I therefore conclude that the appeal should be dismissed.