Appeal 3369343

The appeal is allowed and planning permission is granted for alterations to mansard roof on the front elevation at [site address] in accordance with the terms of the application, Ref 25/00994/FULL, subject to the following conditions:

The development hereby permitted shall begin not later than 3 years from the date of this decision.

The development hereby permitted shall be carried out in accordance with the following approved plans: 19NP-001, 19NP-002, 19NP-020.1, 19NP- 0100.1 and 19NP-200.1.

The materials to be used in the construction of the external surfaces of the development hereby permitted shall be installed in accordance with the details listed within the planning application forms, the glazing bars shall be applied, and along with the window frames, shall painted white within three months of the date of this decision and shall be retained as such thereafter.

The main issue is whether the proposal would preserve or enhance the character or appearance of the Westbourne Conservation Area.

The appeal site is situated within a mid 19th century terrace of four storeys and which have been conserved to a very high standard and include painted, timber sash windows to principal elevations and other fine architectural detailing.

Whilst at roof level, the mansard, the subject of the appeal proposal is visible within the street scene, albeit oblique, and I noted ran counter to the prevailing pattern of mansard roof extensions within the terrace, whereby the majority of dwellings have pairs of sliding sash windows. However, it is not disputed that at the time the appellants purchased the property, it already had wide full-height windows/doors which I understand were previously constructed from uPVC as a replacement in a shade of dark grey. The present replacement aluminium doors are of an overly contemporary appearance and a clear absence of glazing bars does not befit the vernacular of the host dwelling or the terrace of which it forms part.

However, due to the elevated position and the appellants’ intention to apply stick-on glazing bars and paint the window frames white, I consider that it would be extremely difficult to ascertain from street level the nature of the construction material employed for the fenestration.

I acknowledge that the Council consider that on a building of historic merit within a Conservation Area that they would expect the window units to be constructed of timber with integral glazing bars, however I consider that the use of aluminium is a positive step over and above the uPVC which was previously installed and overall I consider that the proposal would, on balance, preserve the character and appearance of the Conservation Area as a whole.

[name] consider that no harm would be caused to either the designated or non-designated heritage assets and I find no conflict between the proposal and Policies 38, 39 and 40 of the City of Westminster City Plan adopted April 2021 which together require that heritage assets and their settings are conserved and enhanced in a manner appropriate to their significance, requiring alterations and extensions to respect the character of the existing and adjoining buildings whilst avoiding adverse visual and amenity impacts; and specifically stipulating that roof extensions will be supported in principle where they do not impact adversely on

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

Other than the standard time limit condition the Council has suggested that conditions be imposed that require the development to be carried out in accordance with the approved plans and that materials to be used in the construction of the external surfaces of the development match those used in the existing building, and requiring the approved windows to be painted white. I have amalgamated the latter two into a single condition (no3) and, bearing in mind that the window material is aluminium, have made reference to the details set out within the planning application forms instead.