Appeal 3362426

The appeal is dismissed insofar as it relates to the first floor extension.

The appeal is allowed insofar as it relates to the rear roof extension and rooflights and permission is granted for a rear roof extension (following removal of existing dormer); and installation of three rooflights to front roofslope at [site address] , Hanwell, London, [postcode] in accordance with the terms of the application, Ref 243880HH, subject to the following conditions:-

The development hereby permitted shall begin not later than three years from the date of this decision.

The development hereby permitted shall be carried out in accordance with the following approved plans insofar as they relate to the roof extension and rooflights only: A2, A100, A202, A204.

The materials to be used in the construction of the external surfaces of the development hereby permitted shall match those used in the existing dwelling.

The Council’s decision refers to the proposed development as ‘Part first floor rear extension; rear roof extension (following removal of existing dormer); and installation of three rooflights to front roofslope.’ As this describes the proposal more fully, I have considered it on this basis.

The main issue in this appeal is the effect of the proposed development on the character and appearance of the area and whether it would preserve or enhance the significance of the Cuckoo Estate Conservation Area (CA).

The National Planning Policy Framework (2024) (the Framework) states that when considering the impact of new development on the significance of a designated heritage asset, great weight should be given to its conservation. I have also had special regard to section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (the Act) as amended.

The appeal site comprises a mid-terraced house that lies within the [name]. The significance of the CA derives from its historic interest as a surviving inter-war London County Council planned estate and from the architectural interest of its remaining original layout that was planned along lines of a traditional garden suburb, consisting of small groups of terraces and semi-detached houses with grassed areas at corners opening up views. Although the dwellings are modest in scale and character, the Council’s Cuckoo Estate CA Management Plan (2007) refers to the cohesive character of the dwellings and this is an important characteristic that contributes positively to the significance of the CA and to the character and appearance of the area.

The dwelling has been previously extended with a flat roofed dormer on the rear roofslope and a single storey flat roofed extension across the rear elevation. The proposed first floor extension, which is the focus of the Council’s refusal, would be sited on the central part of the rear elevation. It would project by just over 2m above part of the existing ground floor extension and would be set in from the edges of the dwelling by around 0.6m.

Although this would be a relatively small extension, the siting of a first floor extension on this mid-terraced house would break up the uninterrupted form of this terrace of six dwellings at first floor level dwelling. Whilst it would not be seen from any public viewpoints, the resulting elevation would be at odds with the cohesive character of the CA referred to earlier. This would be exacerbated by my concerns regarding the proposed hipped roof which would introduce a third roof form to the existing main pitched roof and the flat roofs of the dormer and ground floor extension, resulting in an overly complex elevation of discordant roof forms.

I saw at my visit that the dwelling next door but one to the north-west at no 275 had a larger wrap-around side and rear two storey extension under construction (approved under application Ref. 22483HH) and that other nearby dwellings at no [address] and [address] have two storey hipped roof rear extensions. However, none of those are directly comparable as those are end terrace dwellings and the impact on the rest of the terrace and its rhythm is less than would be the case here for this mid-terraced dwelling. The appellant has also referred to a similar example at [address] but I have no details of the planning status of that extension. Those do not, therefore, provide justification for this proposal.

I conclude then that, by reason of its siting, the first floor extension would fail to preserve or enhance the significance of the CA and would significantly harm the character and appearance of the area. Whilst the harm in this case would be less than substantial, it carries considerable weight and the Framework requires that any harm to, or loss of, the significance of a designated heritage asset, should require clear and convincing justification. Where the harm is less than substantial, it should be weighed against the public benefits of the proposal. The construction of the first floor extension would create a number of jobs over the short term but given its scale this would be of limited benefit to the economy and does not provide sufficient weight to outweigh the harm I have identified. As such, it would be contrary to development plan policies 7.4, 7B & 7C of the Ealing Development Management DPD (2013) and D4 of the London Plan (2021) which together seek to ensure that new development delivers good design that conserves or enhances heritage assets, has a positive visual impact and complements the scale and detailing of the area.

I have noted that the Council has not objected to the proposed replacement of the dormer or the three rooflights proposed on the front roofslope and as those elements are as approved in recent planning applications and would accord with the development plan policies referred to above, they would be acceptable and I shall therefore issue a split decision.

In addition to the standard commencement condition, a condition is necessary requiring that the development is carried out in accordance with the approved plans except for the first floor extension, to provide certainty. A condition for matching external materials is also necessary in the interests of the character and appearance of the site and the area.

For the reasons given above, I conclude that the proposed first floor extension would be contrary to the development plan and there are no material considerations that would outweigh that. The appeal should be dismissed insofar as it relates to the first floor extension.

The proposed rear roof extension and rooflights would accord with the development plan and the appeal should be allowed insofar as it relates to those parts of the proposal.