Appeal 3358982

The appeal is allowed and planning permission is granted for a proposed loft extension at [site address] , Hounslow, [postcode] in accordance with the terms of the application, [name]/2024/3554, subject to the following conditions:

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

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

The development hereby permitted shall be carried out in accordance with the following approved plans: Location Plan; 2024/1/2; 2024/1/3; 2024/1/4; 2024/1/10; 2024/2/5; 2024/2/6 and 2024/2/7.

The main issue is the effect of the proposed development on the character and appearance of the existing dwelling and on the Isleworth Riverside Conservation Area.

The site is within the Isleworth Riverside Conservation Area (CA). The Isleworth Riverside Conservation Area Appraisal (CAA) identifies that the CA encompasses several diverse character areas, with the appeal property falling within the ‘Four Roads Character Area’. It describes this area as comprising a ‘small enclave of late nineteenth and very early twentieth century mostly terraced houses of various styles, which retain many original features such as sash windows, porches and doors. They are neatly laid out on a broken orthogonal grid of streets linked by narrow alleyways which derive from earlier market gardens’.

The appeal property is a mid-terrace, two-storey dwelling with rear outrigger, constructed in yellow stock brick with a slate roof and timber sliding sash windows. Its character and appearance is reflective of this part of the CA and, along with the remainder of the terrace and other nearby terraces, is identified in the CAA as positively contributing to the significance of the CA.

Section 72(1) of the Planning (Listed Buildings and Conservation Area) Act 1990 (the Act) requires that special attention be paid to the desirability of preserving or enhancing the character or appearance of Conservation Areas. Similar advice is contained within the National Planning Policy Framework (2024) and Policy CC4 of the Hounslow Local Plan 2015-2013 (2015) (LP). Policies CC1 and CC2 of the LP expect proposals to respond to the context and character of the area in terms of design, whilst Policy SC7 requires residential alterations to complement the original building and harmonise with adjoining properties.

The proposal is for a rear roof extension. Other than for a single front roof window, the proposed development would not be visible from [address]. The proposed front window would be a velux conservation type roof light which would be flush with the existing roofslope. It would therefore be acceptable in appearance and would not detract from the host dwelling or the surrounding area.

The proposed roof extension would be slightly recessed from the side boundaries and would be finished with vertical hung slates to match existing and the local roofscape. Whilst it would only marginally be set down from the ridge of the dwelling, the roof would gently slope, reducing its ‘box-like’ appearance. The roof extension would meet the eaves of the dwelling and would be a large addition to the roof. The design of the roof extension would not comply with all aspects of the Council’s non-statutory Residential Extension Guidelines Supplementary Planning Document (2017) (SPD), including those applicable to conservation areas.

However, it is also relevant to consider the circumstances of the site. The small rear garden of the dwelling is dominated by a large modern two storey house located close to its rear boundary. Many of the dwellings within the same terrace as the appeal property have been altered and extended to the rear. These include a large flat roof rendered extension on the adjacent dwelling and several roof extensions that can be seen in the same context as the appeal property. There are also various ground floor extensions and windows are of mixed design and appearance. The rear elevation of the nearby terrace in [address] is also visible from the appeal site where several large roof extensions are clearly evident.

The Council highlight that there is no planning history for the roof extensions to Nos 30, 41 and [address] and that the roof extensions at 26 and [address] were approved in excess of 10 years ago and would have been assessed against different policies and guidance. Notwithstanding this, the various extensions and alterations that have occurred form part of the context of the site. The appellant has also highlighted that the Council’s Senior Conservation Officer raised no objection to the proposed development.

Given the short depth of the adjacent gardens and the large two storey building to the rear, very limited views of the roof extension would be obtainable. Any that could be glimpsed, including from [address], would be seen in the same context as the other loft extensions and various other rear extensions and alterations that contribute to the highly mixed appearance of the rear elevation of the terrace. Given this context and having regard to the lack of prominence and views of the development, I conclude that it would not be harmful to the character and appearance of the host dwelling and would preserve the character and appearance and significance of the CA.

Accordingly, the proposal meets the design and heritage requirements of Policies CC1, CC2, CC4 and SC7 of the LP.

I have had regard to the Council’s list of suggested conditions in the event that the appeal is allowed. In addition to the standard implementation condition, the approved plans condition is imposed for clarity. A condition relating to materials is necessary to protect the character and appearance of the CA.

For the reasons given above, and having regard to all other matters raised, I conclude that the appeal should be allowed.