Appeal 3368084

The appeal is dismissed.

An application for costs was made by [name] against the Council. This is the subject of a separate decision.

The appellant has claimed that the dormer extension part of the proposal would comprise permitted development by virtue of the provisions of the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended. However, the application expressly sought planning permission for works including a dormer extension and within the context of an appeal under section 78 of the Act it is not within my remit to formally determine whether this part of the proposed development requires planning permission. If the appellant wishes to ascertain whether the dormer extension could be undertaken lawfully, they may make an application under section 192 of the Act. Notwithstanding, I have considered the evidence as to whether permission is required as far as it is material to this appeal.

The main issues are the effects of the proposal upon the character and appearance of the host dwelling and wider area, and upon the living conditions of neighbouring occupiers at Nos 20 and [address], with particular regard to visual impact and light.

The appeal property is a mid-terraced dwelling with accommodation over three floors, including within a semi-basement. To the rear there is a full-height, gabled outrigger which is shared in common with No 24, and which reflects the development pattern of the wider terrace. The proposal would involve three distinct elements. The Council has no objection to the proposed insertion of four, high level windows on the front elevation to serve the basement. These would be seen just marginally above ground level and I agree that they would be inconspicuous within the front garden setting. To the rear it is proposed to erect a dormer window on the main roof slope, and a single-storey flat roof extension across the full width of the plot and which would wrap-around the side return of the outrigger.

The Council’s Residential Extensions and Alterations Supplementary Planning Document (SPD) was approved in 2009. It sets out a number of guiding design principles, including for rear extensions in general and specifically for single-storey rear extensions upon terraced houses, and for dormer windows on rear roof slopes. It recognises that the composition of the rear elevations of Hackney’s housing stock contributes to its overall townscape. Amongst other things, the SPD advises that all rear extensions must be subordinate to the principal dwelling and that their form should reflect the original building.

The SPD specifically advises that the maximum depth normally acceptable for a single-storey rear extension on a terraced house is 3m. The appeal property has an ‘L-shaped’ footprint with its original rear wall stepped accordingly. From my observations, it appeared that there was originally a shallow, single-storey projection to the rear of the outrigger and another to the rear of the main part of the dwelling. The proposed single-storey extension would incorporate these original elements and would project 3m beyond along the boundary with No 24, as annotated on the plans, and an approximate 9m along the boundary with No 20, as estimated by the Council based on a scaled measurement.

I recognise the SPD provides for some flexibility. This is further demonstrated by examples given within the appellant’s submissions, where the Council has permitted single-storey wrap-around extensions to a variety of depths on other similarly arranged terraced properties elsewhere in the borough. Nevertheless, by projecting to a depth of around 6m beyond that normally permitted where the extension would project to the side of the outrigger, I find its size to be excessive and disproportionately deep at this point.

I observed during my visit that neither adjoining property was extended in any similar fashion. Neither could I detect anything similar to the rear of other nearby properties that could be seen from the appeal site. My impression is that the wrap-around form of the addition would result in an extension overall that would subsume the dwelling at ground floor without any respect for its original form, and which would fail to appear appropriately subordinate within its garden setting. Whilst it would not be seen from the public domain, the addition would not be out of sight but would be observed from surrounding properties and gardens where it would detract from the townscape quality of the surrounding area. Due to its size and visual impact, there would be direct conflict with the guiding principles of the SPD with no circumstances apparent to me to suggest that these should be simply set aside without reason.

The dormer window would sit within the rear facing roof slope and would span its majority width, straddling over the roof of the outrigger. The SPD advises in general that roof extensions and alterations should, amongst other things, be in scale with and proportionate to an existing roof and should reflect the design of the original building. Upon rear roof slopes, it advises that dormer windows should reflect the architectural character of the existing building and its neighbours in their form, detailing and materials, that they should be well spaced and positioned within the existing roof slope, set in from the party wall on each side and down from the ridge, and that generally the width of a single dormer should not exceed half the width of the roof.

The dormer window would rise equivalent to the height of the existing roof’s ridge. The plans ([name] P04) submitted with the application appear inconsistent where they show the height of the dormer above the roof’s eaves. The rear elevation shows the dormer reaching down to the eaves. The left side elevation on the same drawing suggests the dormer would be set up from the eaves by a margin. In any event, notwithstanding the dormer’s set in from both sides, it would fail to meet the SPD’s general guide that they should be a minimum 0.5m below the ridge, a minimum of 1m above the eaves, and should generally not exceed half the width of the roof.

By virtue of its overall size, the dormer would fail to appear as a subordinate rear extension that would reflect the roof form of the original dwelling, instead likely to be seen as a large and bulky addition dominating the rear roof slope and giving the impression of a flat roof additional storey. The two small windows proposed would result in an excessive solid-to-void ratio that would further accentuate its incongruous form. It would precisely reflect the form of extension the SPD guides against. Further, based upon my observations on site, whilst I saw some other large roof additions to other properties in the area, they were not dominant in numbers or representative of a typical roof form within the context of the area’s rear garden settings.

I am mindful that a rear roof addition could be added to the dwelling as permitted development. The appellant argues that the dormer proposed in this instance would be set in 0.5m from the ridge and eaves and that it would be under forty cubic metres in volume with no side facing windows. The plans before me do not reflect all of these factors. They do not reliably show the dormer set up from the eaves or down from the ridge as claimed, and no volume calculations have been provided. I accept a large rear facing dormer constructed as permitted development represents a legitimate fallback position with a real prospect of implementation. However, I am not persuaded by any substantive evidence that such a development would be identical to the proposal that is before me. Whilst any variation between the two may be only slight, based upon the information available to me, the weight I attach to the fallback position is insufficient to outweigh the degree of harm that I have identified in this instance.

Overall, both individually and cumulatively, I find the proposed ground-floor wraparound and dormer extensions would fail to respond positively to the character or context of the appeal property and wider locality. In this regard they would fail to display the design quality required by Policy LP1 of the Hackney Local Plan 2033 (HLP), adopted in 2020, and by Policies D3 and D4 of The London Plan 2021 (LP). For the same reason, and further by failing to have appropriate regard to the SPD, there would be direct conflict with HLP Policy LP17.

The Council describe the single-storey extension along the boundaries with both neighbouring properties as 3.3m high. The appellant asserts the extension would be just 3m high. The plans before me show a single-storey addition with a flat roof that would be 3m high, but with a raised parapet to each side. The plans are annotated to show the height of the extension’s flank walls, including the parapet, to be 3295mm. It is this height that would present itself to both neighbouring properties along both respective adjoining boundaries.

No 20 is unextended to the rear apart from where its original single-storey element to the side of its outrigger and adjacent to the appeal property appeared to have been replaced with a more lightweight, conservatory style projection, but only to an equivalent shallow depth. The proposed extension would project beyond this for a depth of around 9m, which would be excessive and well beyond the 3m depth guide within the SPD. When also considering its height, it would far exceed the height of a normal boundary enclosure, and the existing approximate 2m high timber fence which currently exists. The extension would be further counter to the SPD guidance in this regard which advises that the height of a single-storey rear extension should be kept as low as possible on a boundary to avoid an unacceptable impact on the neighbouring property.

By reason of its depth, height and position, I find that the single-storey rear extension would impose itself at close quarters in the outlook from the rear ground floor living space and from the outside amenity area to the side of the outrigger at No 20 as a dominant and visually overbearing presence. This would be harmful to the living conditions at No 20.

By projecting 3m beyond the existing depth of the outrigger at No 24, which has an original single-storey projection similar to the appeal property, the extension would be compliant here with the SPD in this regard. A similar approximate 2m high boundary fence exists to this side. Given the more limited degree of projection beyond the immediate rear elevation of No 24, the impact upon the outlook from this neighbouring property, and from its garden space, would be minimal.

The rear gardens to these properties are north facing. For this reason, the extension would not impact existing levels of sunlight to the backs of either adjoining property to any significant degree. Neither am I persuaded that existing levels of daylight within the neighbours’ living spaces would be impacted to a degree that would be harmful. Nevertheless, for the reasons I have given, the adverse impacts to the living conditions at [address] means that there would be conflict with HLP Policy LP2 and LP Policy D6 as far as they require development to be appropriate to its context including maximising the usability of outside amenity space in surrounding housing.

The appellant has directed me to three specific examples where planning permission has been granted for single-storey wrap-around extensions comparable in size and nature. I have been provided with details to each of these.

In the case at [address] (Ref 2024/2516) the copy of the officer’s report provided to me is incomplete, with part of its right-hand margin missing making it difficult to get a complete picture. Nevertheless, it is apparent from what I can glean that the nature of the surrounding’s was such that the proposal in that instance was judged acceptable in its setting. In the case at [address] (Ref 2023/2204), it is clear to me from the officer’s report that there was extensive past history, including an identified fallback position with prior approval having been granted for a similarly deep extension. In the case at [address] (Ref 2019/0490), the decision predated the current HLP and in any event the application was jointly made by two neighbouring properties and that a prior approval had been granted for one previously.

Each of the examples given to me demonstrate that similar extensions elsewhere may lawfully exist but that no two circumstances are necessarily the same and that context and site-specific circumstances are key, as is frequently iterated within the SPD. None of the examples given lead me to alter my conclusions on the appeal proposal, which has been considered having regard to its own context and merits.

For the reasons given above, the appeal is dismissed.