Appeal 3319847

The appeal is allowed and planning permission is granted for single storey extension at rear of existing garage at [site address] , Northwood, Hillingdon [postcode] in accordance with the terms of the application Ref 485/APP/2023/128, dated 13 January 2023, subject to the following

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: 2209-PL-120 Rev P1 and 2209-005 Rev P1.

Prior to the commencement of the development hereby permitted, details of the below-ground works and foundation construction of the rear extension shall be submitted to and approved in writing by the Local Planning Authority. Works shall be carried out in accordance with the approved plans and details.

These are the effect of the appeal proposal on the character and appearance of the host property and the surrounding area and its effects on the living conditions of neighbouring occupiers.

The appeal property is a large, detached dwelling of contemporary appearance. It sits on a spacious plot which is typical of the surrounding area. The site is within the Copse Wood Estate Area of Special Local Character (AoSLC). The appeal site is also subject to Tree Preservation Order 396 (TPO).

A Certificate of [name] or Development (CoL) was granted in 2022. This confirmed that the erection of an outbuilding in broadly the same location as the appeal proposal, with the same depth, width and height constitutes permitted development (PD). The only difference between the PD scheme and the appeal proposal is a space of 0.815m between the house and the outbuilding. The evidence indicates that the implementation of the PD scheme is a realistic proposition. The CoL creates a credible fallback position that is a material consideration of significant weight in the determination of this appeal.

From the roadside the rear extension would be screened by the existing garage and its dummy pitched roof. The appeal site is also screened from neighbouring houses to the rear. There would be no impact of the street scene or public views from outside the site. There is no convincing evidence to indicate how the proposed extension would harm the local architectural, townscape, historic merit, or any other special characteristics of the AoSLC.

Policy DMHD 1 of the Hillingdon Local Plan Part Two - Development Management Policies (2020) (HLP) indicates among other things that extensions should be subordinate. It contains detailed guidance on extensions and, of relevance to this appeal, states that rear extensions should be no deeper than 4m and in AoSLCs should be finished with a parapet where a flat roof is proposed. Similarly, among other things, HLP Policy DMHB 5 B) indicates that within AoSLCs extensions to dwellings should be subservient to, and respect the architectural style of, the original buildings and allow sufficient space for appropriate landscaping, particularly between, and in front of, buildings.

The extension would be some 7.9m deep. It would clearly conflict with the maximum depth of extension permitted in Policy DMHD 1. The officer report for the CoL stated that ‘the scale of the outbuilding appears proportionate to the scale of the original dwellinghouse’. Given the similarities between the 2 proposals, it is unclear why a different view on proportionality was reached regarding the current proposal. Having assessed the overall size of the existing property and that of the proposed extension, I conclude that it would be subordinate in size and scale to the house.

The extension would comprise matching materials and would reflect the architectural style of the host dwelling, including by continuing the flat roof design of the existing garage. In this case, the introduction of a parapet as required by Policy DMHD 1 would be out of keeping and contrary to accepted principles of good design. The approved PD scheme would leave a gap between the house and the outbuilding. There is no convincing evidence that moving the extension closer to the house to close the gap would have any material effect on the appearance or impact of the proposed extension.

The extension would be constructed close to the boundary with 20 The Broadwalk (No 20) where the neighbouring property has a tall, mature hedge which is not protected by the TPO. The extension would be set in from the boundary, as would the PD extension. However, as suggested by the appellant, I consider it reasonable and necessary to impose a condition requiring details of the below-ground works and foundation design. This would ensure the appropriate protection of the hedge screen and would also comply with the landscaping requirements of HLP Policy DMHB 6.

Having appropriate regard to the [name] scheme and despite the numerical conflict with Policy DMHD 1, I conclude that the proposed extension would not be disproportionate to the existing dwelling and would not harm its character and appearance, nor that of the surrounding area. The scheme broadly complies with [name] 1 and DMHB 11 and Policies BE1 and HE1 of the Hillingdon Local Plan: [name] - [name] (2012) which in summary require high quality design and, in respect of Policy HE1, the conservation of AoSLCs. Furthermore, the proposal would not harm the character and appearance of but would conserve the [name] as required by [name] 5 and DMHB 6.

Turning to the effect of the extension on the living conditions of the occupiers of No 20, there is a gap of at least 4.7m between the neighbouring kitchen window and the proposed extension. The outlook from this window towards the boundary is interrupted by a pillar supporting a canopy. Notwithstanding that the landscaping could be removed in the future, there is also deep boundary planting in the grounds of No 20 which forms a screen between the 2 properties as discussed above.

Having assessed the distances involved, the location of windows and the intervening boundary treatment, I am satisfied that the proposed single-storey extension would not appear overbearing to the occupiers of No 20 and would not result in an unacceptable loss of sunlight, daylight or privacy. Planning permission has been recently granted at No 20 for a two-storey side extension that would run alongside the boundary with No 18. The approved drawings submitted with this appeal also indicate that, if constructed, the outlook from the nearest room would not be harmed by the proposed development.

Notwithstanding that the impact of the PD outbuilding and the appeal extension on the neighbouring property would be the same, I conclude that the single storey extension would not harm neighbouring living conditions and would not therefore conflict with [name] 1 and DMHB 11 in respect of the requirement to protect neighbouring living conditions.

All other objections made to the proposal, including by the Northwood Residents’ Association, do not affect my conclusions. For the reasons set out above, I conclude that the proposed development in is broad compliance with the aims of the policies identified above. Accordingly, the appeal is allowed subject to conditions.

A condition is necessary requiring the use of matching materials to preserve the character and appearance of the surrounding area. I have included a condition identifying the approved drawings for the avoidance of doubt and in the interests of proper planning. As indicated above, foundation details are required to ensure the ongoing health of the boundary planting. [planning inspector] INSPECTOR