Appeal 3348789

The appeal is dismissed.

The National Planning Policy Framework (the Framework) was updated in December 2024, during the consideration of this appeal. Insofar as is directly relevant to the appeal, there are no substantive changes and no parties have been prejudiced as a result.

On visiting the site and considering the evidence before me, there appeared to be some discrepancies between the existing building on site and that shown on the plans. However, the discrepancies and inaccuracies are not such that they materially alter the scheme before me and there is enough information in the plan drawings considered as a whole for me to understand the proposed development.

The main issues in this appeal are: • the effect of the proposal on the living conditions of neighbouring residents with particular regard to outlook; and • the effect of the proposal on the character and appearance of the area.

The appeal property, [site address] , is a two-storey semi-detached dwelling with accommodation within the roof space facilitated by a fairly large rear dormer window. [address] is a residential road which is largely characterised by similar semi-detached pairs of dwellings set back from the road by small front garden and parking areas.

The proposal is for a first-floor rear extension which would increase the size of bedroom 2 and add an en-suite to that room.

Policy CC2 of the London Borough of Hounslow Local Plan Volume One 2015 – 2030 (LP) states that development will be expected to provide adequate outlook and minimise overbearingness to proposed and adjoining/adjacent dwellings. Policy SC7 of the LP specifically relates to residential extensions and alterations and supports Policy CC2 by setting out that development proposals should minimise harm to neighbouring residents through high quality design.

These policies are supplemented by the Council’s Residential Extension Guidelines Supplementary Planning Document, 2017 (SPD). The SPD is clear that two-storey and first-floor rear extensions potentially have a much more negative impact on neighbours than other types of extension and can cause severe enclosure. In order to minimise such effects, the SPD states that the width of a first floor rear extension should be no greater than half the width of the original house and should not project more than 2.5 metres beyond the rear wall of the house. The SPD also states that the first floor element should be set a minimum of 2 metres from the original side wall of a neighbouring property.

The proposed extension would span the entire width of the rear elevation of the property and would not be set-in from the neighbouring dwelling. As such, the extension would be extremely close to rear windows serving the first floor of the neighbouring property at No. [address]. Whilst the extension would project around 2m instead of the 2.5m set out within the SPD, the proposal would, nevertheless, sit a significant distance forward of the rear building line of the neighbouring property. At such close proximity, the extension would significantly enclose the rear of the neighbouring property and would appear as a visually dominant and excessively obtrusive feature when viewed from the rear windows at No. 22. The proposed extension would appear as an overbearing feature in the outlook from the rear of the neighbouring property.

I accept that the proposed development would not breach the 45 degree line from one of the rear windows and, as such, would not have a detrimental impact on the levels of light reaching this room. I also note that the closest rear window which would be most affected appears to serve a bathroom. Nevertheless, as set out above the proposed extension would cause substantial harm to the outlook from both the rear windows at No. 22 and the overall effect of the proposal would be unacceptable.

For the reasons above, the proposal would cause harm to the living conditions of neighbouring residents with particular regard to outlook. Consequently, the proposal would conflict with Policies CC2 and SC7 of the LP which, amongst other things, seek to retain, promote and support high quality urban design and support the extension of residential properties providing they do not result in harm to the amenity of neighbouring residents. The proposal would also fail to meet the design guidelines set out within the SPD.

The proposed extension would sit above an existing ground floor rear extension. The proposal would be set back from the rear elevation of the extended ground floor and would project around 2m from the rear elevation at first floor level. The top of the proposed flat-roofed extension would meet the existing eaves height of the dwelling.

Though the proposal would not be unacceptable in respect of its forward projection or height, the proposed extension would span the entire width of the property at first floor level. As such, the development would fail to sympathetically respond to and reflect the scale and proportions of the existing dwelling and would visually compete with other elements of the host building. Due to its size and lack of set-in from the side walls of the property the proposed extension would, consequently, not appear as a subservient addition to the property.

Furthermore, the appeal property hosts a number of other additions including a ground floor lean-to structure which extends from the ground floor rear extension and a large rear dormer which spans much of the rear roof slope of the property. The proposed extension would result in a further, separate, addition which would result in a dwelling which would appear as a piecemeal building comprising a number of different elements rather than as a cohesive, singular design.

The proposal would use materials to match the existing dwelling. However, the use of complementary materials would not be sufficient to unify the appearance of the dwelling or reduce the prominence of the proposed extension. The use of matching materials would not, therefore, mitigate the harm I have found to the character and appearance of the host dwelling and the wider area.

Though the proposed extension would be sited to the rear of the appeal property, glimpse views of the side profile of the property would be possible from the street. The appeal property would also be visible from neighbouring properties. Moreover, though a factor to which I have given due consideration, limited visibility alone is not a sufficient reason to allow a development which I consider would cause harm.

For the reasons set out above, the proposal would appear as a visually jarring and incongruous addition which would not sit comfortably with the host dwelling and would cause harm to the character and appearance of the area. The proposal would, consequently, conflict with Policies CC1, CC2 and SC7 of the LP which, in part, expect development proposals to respond meaningfully and sensitively to the site, its characteristics and constraints and support residential extensions and alterations where they complement the original building, harmonise with adjoining properties and maintain the character of the area.

The proposal would also fail to meet the expectations set out within the SPD which states that rear extensions of the type proposed should be proportionate and subordinate to the dimensions of the main house.

I note the appellant’s frustrations with the Council’s approach to determining the planning application. However, this is a matter for the appellant to resolve with the Council directly and it does not have any bearing on my determination of the appeal before me.

I accept that the proposal would meet the fire safety standards set out within the London Plan. I also recognise that there were no objections from neighbouring residents who were consulted about the appeal. These considerations are, however, neutral factors which do not add weight in favour of allowing the appeal and are not sufficient to dissuade me from the conclusions I have reached that the proposal would cause harm to the living conditions of the occupiers of neighbouring properties and to the character and appearance of the area.

For the reasons set out above, the proposal is contrary to the development plan. There are no material considerations that indicate that permission should be granted. Therefore, taking all other matters raised into account, the appeal is dismissed.