Appeal 3317444

The appeal is allowed, and planning permission is granted for infill to existing ground floor rear extension at [site address] , Chiswick, Hounslow, London, [postcode] in accordance with the terms of the application Ref 00371/20/P3 dated 26 October 2022, subject to the following conditions:

The development hereby permitted shall begin not later than three years from the date of this permission;

The development shall not be carried out except in complete accordance with the details shown the following approved plans: site plan dated 17 July 2022, unique reference number #00748727-8064AE, proposed site plan P01, proposed ground floor plan P02, proposed first floor plan P03, proposed second floor plan P04, proposed roof plan P05, proposed rear elevation P07, proposed side elevation P08 and proposed section P09.

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 main issues are the impact of the proposal upon the i) character of the appeal site, surrounding dwellings and the Turnham Green Conservation Area and ii) the residential amenity of neighbouring occupiers with regard to loss of light and outlook.

The appeal site is a two storey, semi-detached, dwelling which stands within the Turnham Green Conservation Area (CA). Section 72 of the Planning (Listed Buildings in Conservation Areas) Act 1990 requires that special attention shall be paid to the desirability of preserving and enhancing the character and appearance of the CA. In this context, preserving can also be taken to mean doing no harm. From the site history, and my site visit, I note that the property already benefits from an existing single storey rear extension which extends to a maximum depth of five metres (on the north side) with the southern side having a depth of four metres.

The proposal seeks to add a gross internal area of three-square metres as a result of infill to the existing ground floor rear extension. I note the change of description in the Council’s delegated report, but the proposal before me is not a new build rear extension following demolition but is in fact an infill extension to the existing built form. The existing depth and massing, and general presence of the existing extension, appears to not have been acknowledged within the Council’s assessment. Whilst the depth of the extension on the southern boundary would increase, by one metre, the overall/maximum depth of the extension would not project further than what is already there in the form of the existing single storey extension. The proposal would, effectively, round off the existing ground floor extension and would be comparable to other examples of large single storey extensions, which the appellant has evidenced as being present within the vicinity. It would not change the character of the appeal site.

The proposal would not be visible from the public realm which limits the impact the proposal could have upon the appearance of the CA and given the presence of other large extensions; the proposal would not be uncharacteristic for the surrounding dwellings. I find that it is, in any case, essentially only matching the overall depth of the existing extension in place. The proposal would represent a small addition and would not, overall (in terms of maximum dimensions), increase the total overall width or depth of the extension, nor increase the height meaning I find that it would respect the host dwelling and not appear visually dominant or out of scale or character with surrounding dwellings.

Overall, the proposed infill extension would merely continue the rear elevation of the current building and would round off the ground floor rear elevation of the house. I acknowledge that this would increase the overall depth of this part of the existing extension to above the maximum depth stated, for single storey extensions that are semi-detached, within the Residential Extension Guidelines Supplementary Planning Document 2017 (SPD). Despite this, it would not project further beyond what is already there and the existing extension already exceeds the guidance. The proposal would only add a small amount to the current footprint and bulk of the house, so is not contrary to the overarching objectives of the guidance stated within the SPD with regard to design.

Taking into account the overall depth of the existing extension, which already exceeds the guidance within the SPD, the evidence of large extensions within the vicinity, and the limited visibility of the proposal from the public realm, I find the proposal would have a neutral impact upon the CA. In accordance with paragraph 199 of the National Planning Policy Framework 2021, when considering the impact of the proposed development on the significance of a designated heritage asset, great weight should be given to the assets conservation. I do not find that the proposal would negatively impact or cause harm to the character or appearance of the appeal property, the surrounding dwellings, or the wider CA and it would, on the basis of doing no harm, preserve the character and appearance of the CA.

Overall, I find the Council’s assessment of the proposal limited, with the assessment appearing to have failed to take into account the existing extension and the proposal in fact being an infill of this. For the reasons outlined above, within this decision letter, I do not find the proposal would be excessive in depth, out of character nor cause harm to the CA.

The proposal would be consistent with London Borough of Hounslow Local Plan 2015 (LP) Policy CC1 which seeks to ensure that all new development conserves and takes opportunities to enhance their special qualities and heritage, LP Policy CC2 which seeks to promote and support high quality urban design and architecture and LP Policy CC4, which expects proposals to conserve any heritage asset and its setting in a manner appropriate to its significance. The proposal would also be consistent with LP Policy SC7, which requires that all alterations and additions do not harm the existing character and appearance of the building and its context as well as respecting the surrounding established context and complementing the original building.

As outlined, within the first main issue, it is acknowledged that the proposal exceeds the guidance as to depth within the SPD for single storey rear extensions. The proposal would, as an infill, add an additional metre to the shortest depth of the existing rear extension (four metres) bringing it in line with the overall depth which is already five metres. The proposal already exceeds the guidance within the SPD in all respects. Notwithstanding this, the SPD is guidance, and it falls to consider the actual impact of the proposal against the overarching objectives of the SPD. The Council’s delegated report raises no concern with residential amenity with the northern boundary (number [address]) and based upon the plans before me, and my site visit, I find no reason to conclude differently on this element.

The neighbour, at number [address] (no. 22), is acknowledged not to have a rear extension, but the Council’s assessment fails to acknowledge the existing extension at the appeal site which is present along the boundary extending to four metres already. At the time of my site visit I noticed extensive vegetation along the boundary, which includes species such as bamboo, and regardless or not as to whether this should be considered as mitigation, it should be noted that no. 22 is directly south of the appeal site. As a result of this, I have no evidence before me to conclude that the proposal would cause unacceptable loss of light, or sunlight, to no. 22 as a result of the appeal proposal. A lack of objection from neighbours is a neutral consideration.

In this case, whilst a line does have to be drawn somewhere with cumulative extension work, I do not find that the proposed infill of around one metre along the boundary would create a change in outlook so significant as to warrant refusal taking into account the existing boundary, vegetation and fencing. The proposal is, overall, a minor change to an already large single storey rear extension. Whilst it would increase depth along the boundary with no. 22 it would not exceed the overall depth already present in the existing extension. The proposal would not realistically change the ability to look outwards or restrict existing neighbour views. Overall, I have no evidence before me to consider that the proposal would cause a loss of light or outlook which would result in such unacceptable impact to neighbouring occupiers that it would warrant refusal in this case.

The proposal would be consistent with LP Policy SC7 which seeks to minimise harm to neighbouring residents, such as avoiding an unacceptable loss of daylight/sunlight and outlook as a result of high-quality design. The proposal is contrary to the overall guidance as to depth contained within the SPD but would be consistent with the overarching objectives of the SPD which is to prevent unacceptable enclosure or loss of daylight and sunlight received by neighbours.

The Council have suggested three standard conditions within their questionnaire which I have applied. The time condition is attached to comply with Section 51 of the Planning and Compulsory Purchase Act 2004. A condition requiring development to be in accordance with the approved plans is required to control and define the development which has granted consent. Conditions relating to materials are required to ensure a satisfactory external appearance.

For the reasons outlined above, and taking account all other matters raised, I conclude that the appeal should be allowed subject to conditions.