Appeal 3350132

The appeal is allowed and planning permission is granted for alterations to hipped roof to provide increased headroom above stair and landing at [site address] , in accordance with the terms of the application [name]/0992/24 and the plans submitted with it, 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: location plan, A358 02, A358 05 and A358 06.

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

I consider that the main issue in this case is its effect on the character and appearance of the area.

[site address] is a two storey semi-detached house in an established residential area within the Canons Park Conservation Area. It has a two storey extension to the side. The significance of this part of the conservation area comes from the Metroland architectural style of the development of the Canons Park estate. This is manifest in the mock Tudor style characterised by strong gables with ‘black and white’ timber detailing and large tiled roofs and at this end of the street, is seen particularly at No. 2 itself and Nos. 4 and 6. Other houses along the street are constructed in many variations on this style.

The relevant policies in this case include D3 of the London Plan (2021), CS1 of the [name] (2012) (the [name]) and DM1 of the Development Management Plan Local Policies (2013) (the DMP) which, among other things, require development to be of a high quality design. The Council’s Supplementary Planning Document [name] (2010) (the SPD) provides detailed advice on residential extensions.

There is a statutory duty under Section 72 of the Planning (Listed Buildings and Conservation Areas) Act 1990 to pay special attention to the desirability of preserving or enhancing the character or appearance of conservation areas. The National Planning Policy Framework (2021) (the Framework) states that in the consideration of development proposals great weight should be given to the conservation of heritage assets in accordance with the significance of the asset and any harm should require clear and convincing justification.

The proposed gable would project from the hipped roof of the two storey side extension with its ridge in line with that of the extension. It would be of a somewhat anomalous form in relation to this roof, but it would be a relatively small addition in the context of the overall height and mass of the host building. I consider that it would not appear unduly prominent either in relation to the house itself or in the wider street scene, since it would be set back from the main front elevation of the house and the road and only partially visible in views along the street from the south or directly in front.

The symmetry of the pair of semi-detached houses is already disrupted by the two storey extension at No. 2, and I consider that the proposal would not amount to a significant increase in that disruption. The timber detailing would reflect that of the existing house and the tiled roof would blend in with the existing tiles, appearing from the front as a continuation of the ridge.

Gables of the style proposed are not common along the street but there are some small tiled ones visible, including at the locally listed No. 3 opposite, where it appears to be part of a large extension to the side. In some respects, the proposal would look similar to the three gables along the side elevation of No. 6 to the north. These have similar timber detailing and are set low down in the hipped roof rather than at ridge height.

The gable would not be readily visible in views from the street due to its location to the side and its set back from the road. It is screened by trees to the south although it would be partially visible when the leaves are off the trees. These trees are protected by virtue of their location in the conservation area, and would therefore be likely to remain substantially as they are in the future.

I consider that the proposed gable, while not wholly consistent with some of the typical roof forms in this part of the conservation area, would nevertheless reflect the character and appearance of many of the nearby houses in its timber detailing and tiling and would be of relatively modest proportions in the context of the overall size and form of the pair of semi-detached houses.

I conclude that the development would not harm the character and appearance of the house itself or the significance of the wider conservation area and that it is consistent with policies D3 of the London Plan, CS1 of the [name] and DM1 of the DMP and the SPD.

For the reasons given above, the appeal is allowed.

I have considered the conditions put forward by the Council, having regard to the tests set out in the Framework. A condition detailing the plans is necessary to ensure the development is carried out in accordance with the approved plans and for the avoidance of doubt. A condition relating to the materials is necessary in order to ensure the satisfactory appearance of the development.