Appeal 3366350

The appeal is allowed and planning permission is granted for ‘ground, first and second floor rear extension of the dwelling, with alterations to the roof including provision of roof lights’ at [site address] , London [postcode] in accordance with the terms of the application, Ref 2025/0729/P, subject to the conditions in the attached schedule.

The description of development in the banner heading above is taken from the planning application form and is broadly consistent with the description stated on the Council’s decision notice. It does not include specific reference to a ground floor rear extension which is additionally shown on the submitted plans. The main parties indicate that this element reflects the extent of a single storey rear extension which has been granted a Lawful Development Certificate1 (‘LDC’). However, the Council’s report identifies that the first and second floor rear extension relies on the construction of the ground floor and the appellant indicates that there are also some minor differences in internal layout from the LDC scheme. I therefore agree with the main parties that the proposal should be considered cumulatively, including the ground floor level.

In addition, the main parties agree that the description of development should be amended to include reference to the ground floor level. Given the nature of the development suggested in the description that interested parties were consulted on and that the ground floor element is clearly shown on the plans that would have been before them, I am satisfied in this case that such a change to the description would not cause unlawful procedural unfairness to any party. I have therefore used this amended description in my formal decision.

The submitted plans also show a proposed basement level. However, the plans indicate that this is being considered as part of a separate planning application and 1 Application ref 2024/4391/P the appellant has confirmed that the basement does not form part of the appeal proposal. It is also clear from the Council’s report that it has not treated the basement as part of the development applied for. I have considered the appeal on the same basis.

The main issues are (i) the effect of the proposal on the character and appearance of the host building and Elsworthy Conservation Area; and (ii) the effect of the proposal on the setting and significance of Primrose Hill Registered Park and Garden.

The Elsworthy Conservation Area (‘the CA’) is generally characterised by terraced townhouses, large semi-detached villas and large detached houses of varied styles which are set in spacious and leafy surroundings. [address] Conservation Area Appraisal and [name] 2009 (‘the CAAMS’) notes that the area developed between 1840 and the early 19th Century, largely through speculative residential development for affluent families, and that the character remains that of a wealthy residential suburb.

The appeal site is located within the ‘Willett Development’ sub-area of the CA which was developed from the late 1890s and predominantly comprises larger detached buildings in a ‘garden suburb’ development pattern. The CAAMS describes the buildings here as of consistently high standard. They are of individual designs, but are typically well-detailed and share common forms and details influenced by the [name] and [name] style, as well as a complementary palette of materials. As a result, there is strong group value.

Insofar as it relates to this appeal, I consider the diverse but architecturally coherent streets and the quality of the buildings arranged within verdant surroundings to contribute much to the distinctive character and appearance of the CA and thereby its significance.

The appellant’s heritage appraisal indicates that the building on the appeal site was built by Willett to plans approved in 1897 in a fusion of vernacular, Arts and Crafts and [name] styles. It is of asymmetric form with the entrance set within an angled porch between the two main sections of the building, and includes a steeply pitched main roof which has three gable projections and a catslide roof with dormer to the rear. The original composition has been modified by later alterations, most notably the addition of a two-storey extension, stair tower and second-floor terrace to the side closest to [address], varied rear extensions, and changes to fenestration including the addition of bay windows. Nevertheless, changes to the front elevation have been relatively limited. It remains a striking building with an irregular footprint and roof typical of the Willett development style, and still shares much in the way of architectural language and form with other Willett buildings nearby.

I therefore agree with the CAAMS that the building makes a positive contribution to the CA. This is most clearly appreciated from the front of the site. However, the CAAMS notes that the original historic pattern of rear elevations within a street or group of buildings is an integral part of the character and appearance of the CA, and highlights views of the rear of properties on [address] and the relationship with [address] to the rear as notable. Significant leaf cover around the rear of the appeal site at the time of my visit meant that only limited glimpses of the rear of the building were possible, but available views would be likely to increase at other times of year. In these views, some appreciation of the retained features and general form of the building would be likely and notwithstanding the past alterations, I find that the rear of the building does therefore make some contribution to the significance of the CA.

The ground floor level of the proposed rear extension would reflect the form and design of the LDC scheme. The first and second floor levels which are now proposed above would be of lesser depth than the ground floor, but would span nearly the full width of the building and would be of comparable height to the existing roof. In those respects, the extension could not reasonably be described as clearly subordinate or subsidiary to the existing building as sought by the CAAMS and the Home Improvement Camden Planning Guidance 2021 (‘CPG’). Nevertheless, the increase in depth would in itself be fairly modest relative to the host building. The design of the extensions including stepped sections, projecting bays and the catslide sections to parts of the roof would also help to break up the impression of mass, and the asymmetric form and footprint of the historic building and the detailing and arrangement of the front elevation would remain legible and prominent.

The proposal would effectively eradicate the building’s existing rear elevation. However, the general form and architectural features of the upper floors of the extension would for the most part replicate the existing building. I appreciate that this would not hold the authenticity of the existing rear elevation, but the architectural value and integrity of the original rear elevation has already been reduced by past alterations including the addition of bay features, changes to fenestration, the addition of an awkward external flue rising up the rear chimney and varying ground floor extensions.

The varied and in some cases poor-quality ground floor level additions to the rear would be rationalised to a single more cohesive form. This would be of different appearance to the existing building and is somewhat lacking in articulation, but it would reflect the LDC scheme. Views of this part of the development would also be very limited given boundary treatment to the site, and I therefore agree with the Council that the design of the ground floor would not warrant withholding permission. Furthermore, the proposal includes the reinstatement of glazing bars to the rear of the first-floor bay closest to No 43 which would be more sympathetic than the existing large pane, as well as the removal of the awkward external flue.

On balance, I consider that the more sympathetic detailing of the upper floors of the rear elevation would offset the loss of existing fabric and details, and that the overall effect on the character and appearance of the rear of the building would be neutral. The contribution that the rear elevation makes to the character and appearance of the building and area would not therefore be harmfully eroded.

Moreover, the rear building line along this part of [address] is not consistent. While the rear of the appeal building would be extended, it would remain set back relative to the rear of [address] and would not project significantly beyond No 43. The position of the rear elevation would not therefore stand out. The appeal building would also retain a generous rear garden and given my findings that its design would be acceptable, I am satisfied that the development would not cause harmful disruption to the pattern or composition of the group of rear elevations here.

Turning to the alterations to the roof, I note guidance in the CAAMS highlighting diverse historic rooflines which it is important to preserve. However, the proposal would maintain the height of the existing main ridge and while there would be an increase in the height of the roof over the side projection closest to No 43, this would remain notably set down from the main ridge and would remain lower than the front gable ensuring a clear sense of subservience. There would not therefore be unwelcome disruption to the general roofline in views along the street.

The extended roof would include crown sections. However, that to the side projection closest to No [address] of a series of varied, contrasting roof forms which have developed over time, including an unsympathetic second floor terrace. Although irregular roofscapes are characteristic within the CA, the complexity of this part of the roof appears awkward and unwieldy, including in glimpses from the street. In my judgement, the simpler, consolidated form proposed would be less conspicuous and discordant against the host building than the existing arrangement. At the same time, its set down would ensure that it retained an ancillary character, and it would not appear unduly bulky or dominate the steeply pitched roof of the host building which is characteristic of the CA.

The roofscape would further include projecting gables, prominent chimneys and catslide sections, including a reinstated catslide to the south east corner which would be more readily appreciated than the existing catslide which is interrupted by the flat roof with terrace. Although there would be some reduction in the overall diversity of roof forms, I consider that there would remain an appropriate degree of articulation and irregularity and sympathetic detail in keeping with typical arrangements in the CA.

Moreover, the close relationship with neighbouring buildings means that there would be very limited opportunities for views of the crown sections. Based on my observations, they would not be readily perceived from the street and while there may be some potential for views of the section closest to No [address], the significant set down from the main roof and comparative set back from the rear of the building means it would not be conspicuous. The appellant has further drawn my attention to examples of crown roofs elsewhere in the CA including at 41 and [address] to the site. The presence of such forms to the appeal building would not therefore stand out.

I acknowledge that there would be change to the dimensions and proportions of the appeal building. From my observations however, its scale and form would not be out of place against other surrounding development in this part of the CA which is generally characterised by large properties, many of which have been extended or altered. Indeed, the flat roof design and resulting considerable bulk and mass of No 43 would remain far more visually prominent, and I am satisfied given all of the above that the additional massing to the appeal building would not appear unduly bulky or dominant.

For all of these reasons, I find that the development would assimilate comfortably with the host building and would be suitably sympathetic to its historic character. It would also maintain the distinctive architectural variety and language of the area as well as the characteristic irregularity of footprints, rooflines and building lines, and would not be an incongruous or prominent feature within its surroundings, including in views from [address]. As a consequence, I find that the proposal would not detract from the picturesque compositional value of buildings or the integrity of the Willett development group overall. Nor would it compromise the integrity or special character of the roofscape or group of rear elevations including the appeal building. In my assessment, the relationship of the site with [address] and the role and contribution made by the appeal building to the character, appearance and significance of the CA would not be adversely affected.

I therefore conclude that the proposal would preserve the character and the appearance of the host building as well as the character, appearance and significance of the CA. It would therefore accord with section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 which requires special attention be paid to the desirability of preserving or enhancing the character or appearance of a conservation area. It would also accord with Policies D1 and D2 of the Local Plan 2017 which include requirements for high quality development that respects local context and character and that preserves or enhances conservation areas. It would not strictly comply with detailed guidance contained in the CAAMS and CPG, but for the reasons detailed above, the effect of the departure on the host building and CA would be acceptable in this specific case.

[address] is a Grade II Registered Park and Garden (‘RPG’) which includes a steeply rising hill laid to grass with paths, some of which are decorated with ornamental trees, offering panoramic views over the City of London, as well as an area where sports pitches have been formed. It was opened for public access in 1842 following its sale to The Crown Commissioners in order to form an extension to Regents Park which is to the south.

Despite boundary vegetation, there is some awareness from within the RPG of surrounding development. This includes the buildings on [address] and insofar as it relates to this appeal, I find the quality and composition of the group of rear elevations including the appeal building and the generally verdant gardens to their rear to complement the RPG and make a positive contribution to its significance as part of the setting.

At the time of my visit, dense vegetation cover meant that views of the appeal building from the RPG were very limited. Opportunities for views would be greater at other times of year when vegetation is not in full leaf. However, I have found above that the proposal would be suitably sympathetic to the host building and that it would not be incongruous or detract from the picturesque compositional value of buildings or the special character of the group of rear elevations which back onto [address]. Given also that the development would not project significantly beyond the neighbours to either side and the generous garden that would be retained, the verdant quality of the space to the rear of buildings on [address] would not be diminished.

On that basis, I am satisfied that the proposal would not detract from existing views from the RPG or the relationship between the park and surrounding development, and I conclude that there would not be harm to the setting or significance of the [address] RPG. As a consequence, I find no conflict with Policies D1 or D2 of the Local Plan insofar as they include requirements seeking development that respects local context and character and that preserves or enhances the historic environment and heritage assets.

I have considered suggested conditions against the tests set out in the Framework. I have made amendments where necessary to ensure compliance with these tests or for clarity, brevity or consistency.

I have imposed the standard time limit condition, and a condition specifying the approved plans for the avoidance of doubt and in the interests of certainty. Conditions to specify the materials, to define the extent of demolition and to require protection for trees are necessary in the interests of character and appearance. I have also imposed a condition to require flank windows to the upper floors of the building to be obscure glazed and restricted opening which I consider would be necessary to prevent overlooking in the interests of neighbouring living conditions.

For the reasons given above, I find that the proposal would accord with the development plan when it is read as a whole, and material considerations do not indicate that a decision contrary to the development plan should be reached. I therefore conclude that the appeal should be allowed.

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

Unless otherwise amended under the conditions below, the development hereby permitted shall be carried out in accordance with the following approved plans: 2502 PL-001 Rev 0, 2502 PL-051 Rev 0, 2502 PL-052 Rev 0, 2502 PL-150 Rev 0, 2502 PL-151 Rev 0, 2502 PL-152 Rev 0, 2502 PL-160 Rev 0, 2502 PL-170 Rev 0, 2502 PL199 Rev 0, 2502 PL-200 Rev 0, 2502 PL-201 Rev 0, 2502 PL-202 Rev 0, 2502 PL-300 Rev 0 and 2502 PL-310 Rev 0; except in respect of the proposed basement level shown on plan Nos. 2502 PL-200 Rev 0 and 2502 PL-310 Rev 0 which does not form part of the development hereby permitted.

The extent of demolition shall be limited only to that indicated on the approved plans including in particular Plan Nos. 2502 PL-051 Rev 0 and 2502 PL-052 Rev 0.

With the exception of the aluminium door system to the ground floor of the rear extension which shall be constructed in the materials shown on plan no. 2502 PL-300 Rev 0, 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.

All works of demolition and construction shall be carried out in accordance with the relevant recommendations of [name] 3998: 2010 (Recommendation for Tree Work) (or equivalent standard if replaced).

The development hereby permitted shall not be occupied until first and second floor level windows to the side elevations of the development hereby permitted have been fitted with obscured glazing, and no part of the window that is less than 1.7 metres above the floor of the room in which it is installed shall be capable of being opened. Details of the glazing shall be submitted to and approved in writing by the Local Planning Authority before the relevant window is installed and the window shall be installed in accordance with the approved details and shall thereafter be retained. End of Schedule