Appeal 3357624

The appeal is allowed and planning permission is granted for a proposed rear dormer loft conversion and changing from a hipped to a gable roof and a proposed rear first floor extension at [site address] in accordance with the terms of the application, [name]/2024/2816, 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, BP1, 01, 02, 03, 04, 05, 06, 07; and the [name]

The main issue is the effect of the proposed development on the character and appearance of the host dwelling and surrounding area.

The appeal property is a two storey dwelling located in an area comprising properties of a similar original design and appearance. The proposal is for a rear dormer loft conversion, a hipped to a gable roof and a proposed rear first floor extension.

Policies CC1 and CC2 of the London Borough of Hounslow Local Plan 2015-2030 (2015) (LP) expect proposals to respond to the context and character of the area in terms of design. Policy SC7 of the LP requires development proposals to complement the original building and for extensions to have regard to the quality, character, materials and scale of the principal building, be subordinate to the existing building and not overdevelop the site in terms of mass and density. The Council’s Residential Extensions Guidelines Supplementary Planning Document (2017) (SPD) whilst non-statutory, provides further useful design guidance.

The appeal property is a mid terrace dwelling, with a hipped roof form. The terrace is already unbalanced through the addition of No 23A which, although set back from the front elevation of No 23, is of considerable width. Many of the surrounding dwellings have also been heavily extended to the side and rear. Hip-to-gable roof extensions are common, as are large rear box dormers. These alterations and extensions have reduced on the rhythm and uniformity of the streetscene, with many pairs of semi-detached houses appearing unbalanced.

The proposed hip-to-gable extension would further alter the appearance of the terrace but, as a matter of judgment, would not be harmful to the character and appearance of the host dwelling, the wider terrace or the area given the extent of alterations that have taken place locally and the overall lack of rhythm and uniformity in the street scene. The proposed rooflights on the front elevation are also small in size and similar to those on neighbouring dwellings.

With regard to rear dormers, the SPD states that the Council will normally refuse roof extensions that would be as wide as the house and create the appearance of a large box. As a guide, it advises that any roof extension to the rear of a terrace house or smaller semi-detached house should be at least 0.3m below the ridge level, at least 0.5 above eaves level and at least 0.5m from the side of the roof.

The proposed rear dormer would extend across the full width of the dwelling and would not be set down from the ridge or significantly up from the eaves. Accordingly, it does not comply with the guidelines contained within the SPD. Notwithstanding this, it is important to recognise that such guidance does not constitute a rigid set of rules to be applied exclusively when other material considerations indicate that an exception may be appropriate.

The proposed roof dormer would be ‘box like’ in appearance and would dominate the rear roof of the dwelling. However, it would be similar in its scale, design and appearance to many other dormer extensions in the immediate area, many of which are more prominently located and clearly visible from public vantage points. The Council has stated that most of the other rear dormer additions have been constructed in accordance with permitted development rights. However, notwithstanding this, the various hip to gable extensions and rear dormers that have occurred form part of the context of the site and are therefore an important consideration.

The proposed rear dormer would not be visually prominent in the public domain as it would be well screened from the nearby [address] (A316) by a belt of trees. Whilst it would be visible from neighbouring properties, it would be seen in the same context as other similar rear dormer extensions in the area and would not, therefore, appear out of keeping or harmful to local character.

The SPD advises that first floor extensions should be proportionate and subordinate to the dimensions of the main house and that the width of a first-floor rear extension should be no greater than half the width of the original house.

The proposed first floor rear extension would extend across slightly more than half the width of the main house, although a reasonable part of its original first floor rear wall would remain visible. Furthermore, it would have a very shallow depth and would not extend beyond the two storey rear elevation of the adjacent dwelling, [address]. It would also have a flat roof design and would sit beneath the proposed rear dormer. Given its limited depth and height and its siting in relation to the rear elevation of No 23A, it would not be excessive in scale and would not overwhelm the host dwelling. The rear extension would not appear as a bulky or discordant feature when viewed from the private domain and as with the rear dormer, would not be readily visible from any public vantage points.

For the above reasons, I find that the proposal would not have a harmful effect on the character and appearance of the host dwelling or the surrounding area. Accordingly, it would comply with the design objectives of Policies CC1, CC2 and SC7 of the LP, the London Plan (2021) and the National Planning Policy Framework (2024).

Third party comments relating to the works that have already taken place at the appeal site are not relevant to the appeal proposal which I have considered on its merits.

The proposed rear extension would be level with the two-storey rear elevation of [address]. It would set in from the boundary with [address] and given its shallow depth, would not result in any significant loss of light to either dwelling. The alterations at roof level would not have any material effect on the amount of light received by neighbouring windows or rear gardens. Whilst the proposal would introduce further windows on the rear elevation of the dwelling, including at roof level, the proposal would not result in any unacceptable level of overlooking of neighbouring dwellings beyond that which can reasonably be expected in an urban area.

In addition to the standard implementation condition, the approved plans condition is imposed for certainty. A condition requiring the use of matching materials is necessary to protect the character and appearance of the dwelling and the local area.

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