Appeal 3319796

The appeal is allowed and planning permission is granted for the extension of main roof hip to form a gable end, erection of rear dormer extension and loft conversion at [site address] in accordance with the terms of the application, Ref 01042/18A/P1, dated 8 January 2023, subject to the following conditions:

The development hereby permitted shall be carried out in accordance with the following approved plans: P9256/OS; PA9256-00; PA9256-01 and PA9256-02.

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.

At the time of my site visit, the dwelling was undergoing complete renovation with the proposed hip to gable extension and a rear dormer extension well advanced. I noted that the rear dormer under construction differs in terms of its design to the appeal proposal. However, I am required to determine the appeal on the basis of the plans and other information before me, as submitted to and determined by the Council.

The main issue is the effect of the proposal on the character and appearance of the host dwelling, the semi-detached pair and the surrounding area.

The appeal property is a semi-detached dwelling located at the end of [address]. It is attached to [address] which has a two-storey extension to the side and a dormer window on its original rear roof slope. The surrounding area comprises of semi-detached and detached dwellings which display both hipped and gable roof forms. I noted at my site visit that several nearby dwellings also have rear dormer extensions.

Policies CC1 and CC2 of the London Borough of Hounslow Local Plan 2015-2030 (2015) (LP) expect proposals (amongst other things) 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 Council’s Residential Extensions Guidelines Supplementary Planning Document (2017) (SPD) whilst non-statutory, provides useful design guidance. The SPD generally advises against hip to gable extensions due to the resulting unbalanced appearance of the house and semi-detached pair. With regard to rear dormers, it 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 appeal proposal 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 appearance of the semi-detached pair is already unbalanced as No 16 has a two storey extension to the side. However, this extension has a hipped roof to the side which matches the original roof form and accordingly, the proposed gable end to No 18 would further unbalance the appearance of the pair of dwellings.

However, the pair of dwellings are set at an angle to the turning head at the end of [address] with the appeal property being the end dwelling. The side elevation of No [address] such that it is not visually prominent in the street scene. As the pair of dwellings do not sit within a uniform street scene comprised of similar hipped roof dwellings, I do not consider that the hip to gable extension would have a particularly harmful effect on the character and appearance of the host dwelling or the semi-detached pair, particularly as there are other dwellings along [address] which display side gables, including the adjacent detached dwelling. Given the above reasons and the mixed character and appearance of [address], I conclude that the proposed hip to gable extension would not be harmful to the character and appearance of the area.

The proposed rear dormer would extend across the width of the roof of the dwelling with only a relatively small set back from the eaves, ridge and side of the roof. It would therefore be a dominant feature of the roof of the dwelling and would be considerably larger than the dormer on the rear elevation of No 16. However, the site is extremely well screened and external views of the dormer would be limited such that it would not have any material effect on the character and appearance of the wider area. I also noted that several of the surrounding dwellings, including at [address], also have large box dormer additions and the proposal would not be out of keeping in this regard.

The appellant has also referred to the planning history of the site, and in particular to an application for a Certificate of Lawfulness1 for the same development. This application was refused as the Council disputed whether the dwelling was in use at that time as a single family dwellinghouse, rather than due to the dimensions of the proposal. Notwithstanding that the Certificate was refused, I am mindful that in many circumstances the proposed hip to gable extension and roof dormer would be likely to constitute permitted development which further weighs in favour of the development.

I find, on balance, that the proposal would not have a harmful effect on the character and appearance of the host dwelling, the semi-detached pair or the surrounding area. Accordingly, it would comply with Policies CC1 and CC2 of the LP which expect proposals to respond to the context and character of the area in terms of design and Policy SC7 of the LP which requires residential alterations to complement the original building and harmonise with adjoining properties.

As the proposed development is well advanced, the standard implementation condition is not necessary. 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.