Appeal 3361884

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

The appeal is allowed insofar as it relates to the rooflights and permission is granted for the installation of two roof lights to front roof slope at [site address] , Hanwell, London, [postcode] in accordance with the terms of the application, Ref 243724HH, 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 rooflights only: 02, 03, 04.

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 ‘Rear roof extension and installation of two roof lights to front roof slope.’ 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 dwelling and whether it would preserve or enhance the significance of the Hanwell Village Green 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.

[site address] is a two storey, pitched roof end terrace house that is likely to have been built in the Edwardian era. It is sited close to the village green in a part of the CA that is leafy with open spaces and traditional dwellings, giving it a rural village character. The CA Appraisal (2008) noted that the Victorian and Edwardian properties generally are very cohesive and have been relatively immune from inappropriate minor development and the Addendum (2020) noted that remains the case.

Like most of the other dwellings in the terrace, it has retained many of its original features on the front elevation but the rear elevation has been much altered. It has been previously extended with a single storey extension with a lean-to roof across the rear elevation and with a first floor flat roof extension above part of that.

The Hanwell Village Green Conservation Area Management Plan (2008) requires that dormer windows do not dominate the roofslope and the Council’s Generic Management Plan for Conservation Areas (2023) states that they should take up no more than two thirds of the height of the roof. The plans show that the proposed flat roof dormer of some 5.6m in width would occupy most of the 6.75m or so width of the roof. At 2.3m in height, it would be set down only 0.22m from the main ridge instead of the 0.5m required under the [name] and would be set back from the eaves by only 0.5m. The appellant says this is necessary for practical reasons to provide sufficient internal floor-to-ceiling height. However, as such, and despite its matching materials, the size and scale of the proposed dormer would be excessive and would dominate the roofslope. As none of the other dwellings in the terrace have rear roof extensions, it would be particularly conspicuous and would result in an overly bulky addition.

The proposed extension would not be visible from [address] but, even though it would be partly screened by surrounding trees, it would be clearly seen from an access road to Brent Valley Golf Course and [name].

The appellant has referred to other examples of rear dormers within the CA including at 6 and [address] but those are smaller in scale and less prominent, located within a cul-de-sac and sited on a modern terrace in which there were existing roof alterations. They do not, therefore, provide justification for this proposal.

I conclude then that, by reason of its size, scale and bulk, the proposed roof extension would significantly harm the character and appearance of the dwelling and would fail to preserve or enhance the significance of the CA. 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. However, in this case, I have not been told of any benefits that are sufficient to outweigh that harm. As such, the proposed roof extension would be contrary to development plan policies 7.4, 7B & 7C of the Ealing Development Management DPD (2013) and D4 & HC1 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 two rooflights proposed on the front roofslope. As those would be small in scale and of a conservation style, they would not harm the significance of the CA or the setting of [address], a [name] listed building opposite. They would accord with the development plan policies referred to above 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 roof 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 roof 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 roof extension.

The proposed rooflights would accord with the development plan and the appeal should be allowed insofar as it relates to that part of the proposal.