Appeal 6004517

The appeal is dismissed.

I have taken the description of the proposed development in the banner heading above from the Council’s decision notice, avoiding superfluous wording, as this gives a more concise description of the proposal.

The main issues are: • whether the proposed development would preserve or enhance the character or appearance of the Watling Estate Conservation Area (CA); and, • the effect of the proposed development upon the living conditions of occupiers of [address], with particular regard to outlook.

The appeal property is a terraced house within the Watling Estate Conservation Area (CA). The special interest of the CA derives from its verdant open layout and house designs which are similar in scale and form and reflect the garden suburb principles applied to the estate design, which are referred to in the Watling Estate Conservation Area Character [name] (2007) (CACAS). The appeal property, and the adjoining house, No 8, have ground floor canted bay windows and share a recessed porch with a timber surround and turned spandrels on each side, features which are identified in the CACAS as contributing to the character of the area. Appeal Decision: 6004517

The CACAS identifies the addition of porches in a list of unsympathetic alterations which detract from the special character of houses within the CA. The proposed development includes replacing the recessed porch and timber features with a projecting mono-pitched roofed porch. It would result in the loss of an original design feature noted as contributing to the character of the area and would thus fail to preserve or enhance the appearance of the CA.

The appellant has stated that it would be joined to a similarly designed porch at No 8 to maintain symmetry between the houses. However, I have no evidence that an application has been submitted for an adjoining porch which would, in any case, not mitigate the harm that I have identified. I note that several houses within [address] have modern porches, including No 4 which also adjoins the appeal property, but that does not justify the further loss of an important feature that contributes to the character of the CA.

The proposed development would also replace a rear open sided wood framed lean-to with a single storey extension. It would be the same height width and depth as the lean-to but would appear more solid and bulky because the open sides would be replaced with brick walls and the opaque polycarbonate roof would be replaced with a tiled roof.

The Council’s Residential Design Guidance Supplementary Planning Document (2016) (SPD) advises that rear extensions of 3m depth on terraced houses are normally acceptable. That corresponds with the depth of the neighbouring rear extension on No 8. The proposed extension would be 4.2m deep, thus substantially exceeding the acceptable depth in the SPD and that of the adjoining rear extension, in the context of which it would appear overly large and out of proportion. Although it would match the depth of the existing lean-to, that structure is open on three sides and has a light and airy appearance. In contrast, the proposed extension would have solid side and rear walls and thus appear bulkier, drawing attention to the difference in rear building lines between it and the neighbouring house.

Views of the proposed extension would be limited to the first-floor rear windows of houses within the same terrace and on [address] close to the appeal site. Nonetheless, from these views it would appear out of proportion and interrupt the pattern of development in the area due to its excessive depth.

Given the small scale of the proposed development within the context of the CA as a whole, it would not harm its character. There would, however, be harm in terms of its appearance. The harm would be localised and less than substantial but would nevertheless be contrary to Policies CDH01, CDH05, and CDH08 of the Barnet Local Plan (2025) (BLP), Policies D3 and HC1 of the London Plan (2021) (LP), the SPD, and Section 72 of the Planning (Listed Buildings and Conservation Areas) Act 1990, which require development to respond sensitively to local character.

Any harm to the significance of a designated heritage asset requires justification and, in accordance with paragraph 215 of the Framework, I must weigh the harm against the public benefits of the proposal. There would be modest benefits arising from improved living accommodation and employment during construction. However, such benefits would not outweigh the harm to the appearance of the Watling Estate Conservation Area. Appeal Decision: 6004517

No 4 has a rear patio below the level of the rear of the appeal property with patio doors that open out on to it which are correspondingly lower than the height of the appeal property ground floor windows. Consequently, the boundary fence and existing lean-to will appear higher from No 4 than from the appeal site. The lean-to’s open sides break up its mass, providing a gap between the top of the fence and the lean-to roof which prevents it from appearing excessively overbearing.

As already noted, the proposed extension would replace the open sides with brick walls and the polycarbonate roof with a tiled roof. It would fill the gap between the fence and roof creating a bulkier structure which would be significantly more visually intrusive than the lean-to. It would thus have a more overbearing presence when viewed from No 4’s patio doors and rear garden.

The appellant has referred to a lack of evidence that the extension would breach a 45-degree line taken from the centre of the patio doors. I have not been provided with plans to enable such an assessment, which in any case is not a requirement set out in either the SPD or the Council’s policies. However, based on my observations during my visit, I conclude that the proposed extension would appear overly dominant because of the difference in site levels and additional bulk and result in unacceptable harm to the neighbour’s outlook.

Overall, I conclude on this main issue that the proposed rear extension would conflict with the SPD, Policy CDH05 and Policy CDH08 of the BLP and Policy D3 of the LP, which seek to maintain adequate outlook and ensure that extensions are not overbearing or unduly obtrusive.

The appellant has referred to recent planning approvals for rear extensions on [address], including at No 20. However, no details of these proposals have been provided to me. I am therefore unable to assess any direct comparability with the current appeal proposal. In any case, I have come to my own view regarding the development rather than relying on the approach the Council may have taken elsewhere.

The orientation of the houses is such that the proposed rear extension would have little effect on the amount of light to neighbouring properties. However, notwithstanding the comments in the Council Officer’s Report, overshadowing was not referred to in the reasons for refusing the application.

For the reasons given above, and having regard to all matters raised, I conclude that the appeal should be dismissed.