Appeal 3330286

The appeal is allowed, and planning permission is granted for a part three storey and part single storey rear extension and associated works at [site address] in accordance with the terms of the application, Ref 23/1247/HOT, dated 5 May 2023, and the plans submitted with it, subject to the conditions in the attached schedule.

The proposal comprises several elements. The Council has not raised any objections to the part three storey or the side elements of the extensions, and from my observation on site, I have no reason to disagree. Therefore, my considerations are primarily restricted to the single-storey rear extension.

The main issues are the effect of the development on: - i) the occupiers of the neighbouring property, [address], with regard to visual intrusion and overbearing impact; and ii) flood risk.

[site address] is a three-storey semi-detached property. The front door is accessed up several steps and to the rear the lower level of the property has steps up to the garden area. The proposed single-storey extension will extend the lower ground floor to the rear. It will require some ground excavation to align the floor levels, but a large proportion of the structure would be above the existing ground level.

The flat roof of the extension would be below the level of the shared boundary, which is substantial comprising a wall with fencing above and over 3 metres in height. The fencing has a slattered form which does allow some light through, nonetheless, it restricts intervisibility between the neighbouring properties. While the extension would project some distance into the garden, due to its limited height and the existing boundary treatment it would not be directly visible from the neighbouring property. The boundary is higher than a typical garden fence, but there are differences in ground levels, and the height of the extension is not excessive. Additionally, the design features including the winter garden adjacent to the rear of the property and the green roof would break up the massing and soften the appearance of the extension.

The Council indicate that No.28 has been divided into flats, and reference plans for an application in 2019 that show patio doors to a terrace at the lower ground level adjacent to the shared boundary. However, there is no evidence before me to indicate that scheme has been implemented and more recent aerial photographs provided by the appellant do not show that arrangement to the rear. In any event, given the scale and form of the single-storey extension, I do not find it would result in a significant overbearing impact to cause a harmful sense of enclosure.

I therefore conclude that the development would accord with policy LP 8 of the Local Plan1 which seeks to protect the amenity and living conditions for occupants of neighbouring properties including from visual intrusion and overbearing impact.

Policy LP 21 of the Local Plan seeks to ensure that all developments avoid or minimise contributing to all sources of flooding. The proposal is supported by a Flood Risk Assessment (FRA) and identifies the site as within [name] 1. Within this zone, the policy indicates that there are no restrictions including for new or extensions to existing basements. The officer’s report acknowledges the FRA and indicates that the proposal would be compliant with Policy LP 21. Notwithstanding this, the Council go on to find conflict against the flood risk criterion (5) of Local Plan Policy LP 11 which relates to basement development.

Policy LP 11 does not define a basement with the supporting text just indicating that this policy applies to all new basement developments, including the construction or extension of one or more storeys below the prevailing ground level of a site or property.

This is not a proposal for the creation of an extra floor under the existing property, nor is it a subterranean development. Whilst the development has a ‘sunken’ element to align the floor levels the majority of the building would be above existing ground level with the excavation required extending to approximately 0.7-0.8m. As such, I agree with the appellant that the proposal is more accurately described as a single-storey extension (as identified on the planning application) rather than a basement. In support of this view is that the other main issue, as considered above, relates to overbearing impact which would not be an issue (or would be highly unlikely to be the case) with a development for a basement which is primarily underground.

As such I do not find Policy LP 11 to be directly applicable to this proposal and the specific details sought by the Council in relation to the Basement Assessment User Guide are not required. Notwithstanding this, the FRA 1 London Borough of Richmond Upon Thames Local Plan adopted 3 July 2018. concludes that there would be betterment in flood risk terms through the incorporation of [name], which the Council acknowledges.

Consequently, I find that the proposal would not adversely impact flood risk and would accord with Local Plan Policy LP 21.

In line with the statutory requirements and for certainty conditions are imposed to ensure the scheme is carried out in accordance with the appropriate timescale and the submitted plans. It is also necessary in the interest of the appearance of the property and its Conservation Area setting for the materials to match the existing property. Additionally, as the extension would create a large flat roof area at first floor level it is necessary in the interests of the living conditions of neighbouring residents to restrict its use.

I have not been referred to any planning policy requirement for the restrictions to site machinery and as the proposal relates to a domestic extension, I do not find that the suggested condition is reasonable or necessary. Similarly, as this is not the development of a basement, a condition to secure a construction management plan in line with Policy LP 11 is also unnecessary. However, a condition is required to secure the fire safety plan in line with the London Plan.

For the reasons set out, I have not found harm to the neighbour’s living conditions or flood risk, and there are no other matters that indicate the proposal should be determined other than in accordance with the Development Plan. I therefore allow the appeal.

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

The development hereby permitted shall be carried out in accordance with the following plans: GR- 001 A - Existing location and proposed block plan; GR-103 B - Existing and proposed third floor plan; GR-202 B - Existing and proposed side elevation; GR-300 B - Existing and proposed section DD; GR-102 E - Existing and proposed second floor plan; GR-105 B - Existing and proposed roof plan; GR-201 C - Existing and proposed rear elevation BB; GR-200 B - Existing and proposed first front elevation; GR-101 E - Existing and proposed first floor plan; and GR-100 D - Existing and proposed ground floor plan.

The roof of the building shall not be used for any purpose other than as a means of escape in an emergency or for maintenance of the building.

The materials to be used in the external surfaces of the extension hereby permitted shall match those of the existing dwelling, except where indicated otherwise on the approved drawing.

The development must be carried out in accordance with the provisions of the submitted ‘Planning Fire Safety Statement’.