Appeal 3346461

The appellant described the proposal as ‘a semi-detached house where a first-floor extension has been built and proposing a pitched roof instead of existing flat roof’. I consider that the Council more accurately describes the appeal proposal and its wording has been used as the description of development in the heading above.

A flat roofed, first-floor side extension has already been constructed.

The appeal is dismissed.

The main issue is the effect of the appeal proposal on the character and appearance of the host property and the surrounding area.

The appeal property (No 15) is an end of terrace, two-storey dwelling located on the north side of [address]. The surrounding area is residential, containing similar properties. To the north of the appeal site is a woodland area of open space. No 15 stands at the end of a row of terraced houses, as does the neighbouring property (No 17). There is a gap between them which is emphasised by their differing orientation and hipped roofs.

An appeal for a first-floor side extension with a flat roof, reflecting the development as built, was dismissed in September 2023 (reference APP/R5510/D/23/3324073). Among other things, the Inspector concluded that the first-floor extension harmed the character and appearance of the host dwelling. This decision is material to the appeal before me.

The current appeal proposes a pitched, hipped roof with a window in the first-floor front elevation. In principle, this design approach would better reflect the form of No 15 and would improve the appearance of the existing extension, including by reducing its currently somewhat ‘boxy’ appearance.

However, the previous Inspector found that the forward projection of the first-floor front elevation produced an awkward and dominant structure. This element remains in the revised scheme. I agree with the conclusion of the Inspector. Notwithstanding that the extension would remain less than half the width of No 15, there would be no ‘step in’ from the ground floor side extension, no ‘set back’ at first floor level or any other measure that would minimise its bulky appearance. The proposed development would not be sufficiently subordinate to the host dwelling.

The forward projection would also affect the design and construction of the proposed roof, resulting in an incongruous roof form that would jar with the design of the main roof of No 15 and would harm the appearance of the terrace. It would also contrast unacceptably with the roof of No 17 whilst increasing the visual terracing effect between the two neighbouring houses. The proposal would lead to a cramped appearance within the street scene, notwithstanding the slightly splayed siting difference between the two blocks of terraces.

Some extensions in the immediate area are unsympathetic to local character. However, the existence of poor-quality design is not a good reason to permit further development that would add to this harm.

For the reasons set out above and having regard to all other matters raised, I conclude that the proposed extension would harm the character and appearance of the host dwelling by reason of its size, siting and design and would not be sufficiently subordinate. The proposal would result in a cramped and incongruous development which would harm the character and appearance of the wider street scene. For these reasons, the proposed development fails to comply with Policies DMHD1 and DMHB 11 of the Hillingdon Local Plan: [name] - Development Management Policies (January 2020).

Accordingly, the appeal is dismissed.