Appeal 3347936

The appeal is allowed and planning permission is granted for the installation of rear dormer to existing first floor room at [site address] , [site address] , Barnet [postcode] in accordance with the terms of the application, Ref 24/1632/HSE, subject to the following conditions:

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

The development hereby permitted shall be carried out in accordance with drawing nos SK01-1, SK01-2, SK01-3, SK01-4, SK01-5, SK01-6.

The external materials of the extension hereby permitted shall match those used in the existing building/dwelling.

Following the submission of the appeal, a draft revision to the National Planning Policy Framework was issued for consultation alongside a [name]. Neither introduce issues relevant to the pertinent considerations in this appeal and therefore I have not sought comments on it from the parties.

The new local plan is at regulation 24 stage. It will now be subject to a period of formal consultation. Although the new local plan is at an advanced stage and is a material consideration, at the current time it does not form part of the statutory development plan. As such, I give it only limited weight in my assessment of the appeal.

The main issues are: • whether the proposal would be inappropriate development in the Green Belt having regard to the National Planning Policy Framework (the ‘Framework’) and any relevant development plan policies; and • the effect of the development on the appeal property and the character or appearance of the Monken Hadley Conservation Area (MHCA) and whether it would preserve the setting of the [name] listed building Hadley Bourne1.

The National Planning Policy Framework 2023 (the Framework) explains that the essential characteristics of Green Belts are their openness and permanence. There is a general presumption against inappropriate development in the Green Belt (GB) unless very special circumstances exist. The construction of new buildings should be regarded as inappropriate, but for defined exceptions.

Barnet’s Local Plan (Development Management Policies) Development Plan Document 2012 (DMP) Policy DM15 states that certain forms of development are not inappropriate in the GB. This includes the extension of existing buildings ‘where they do not result in a disproportionate addition over and above the size of the original building.’ This stance is reflected in paragraph 154 of the Framework which also allows for extensions to existing buildings in the GB, as an exception, on the provision that they are not disproportionate.

Further, guidance on what is considered to be a disproportionate addition in the GB is provided in paragraph 14.48 of the Local Plan Supplementary Planning Document: Residential Design Guidance (SPD) which states ‘ as a guiding principle the volume of the original building should not be increased by more than 25% by external measurement in order to protect openness.’

There is no dispute between the main parties that the appeal building has not been extended previously. Based on the evidence before me the proposed extension would represent an increase of approximately 3%. Paragraph 14.49 of the SPD goes on to state that there may be instances where an extension of less than 25% is appropriate. However, in this instance the site is not prominent and given the modest increase, as a result of the proposed extension, it is not inappropriate.

In conclusion the proposed dormer window would not be inappropriate development in the GB having regard to the Framework. Although not cited within the reasons for refusal on the decision notice, Policy DM15 of the DMP has been referenced in the Officer report, which also seeks to protect the GB from inappropriate development.

[site address] was originally erected as a greenhouse within the grounds of [name] a [name] listed former convent, set back from the highway amidst attractive mature gardens. The scale and position of [name] increases its prominence within the street scene. [site address] does not have a public frontage and is not clearly visible from the public realm. Notwithstanding this, it is a well preserved example of an ancillary building that has been sympathetically altered utilising a palette of traditional materials to allow for its current use as a dwelling. 1 1078840

The significance of this part of the conservation area is defined, in part, by the lower building density and varied and high quality architecture. These factors, along with mature gardens and parkland, combine to give the area a verdant village feel that contrasts with surrounding areas where the building density is higher and more suburban in character.

[address] is several metres from [name] and its smaller scale and lower profile ensures that is clearly reads as being subservient to the building it originally served. The utilitarian former use is evident in its simple built form and materials. This differs from [name] which is of is of a significantly grander scale and includes finer architectural detailing, which sets it apart as the main building. The MHCA derives much of its character and appearance from listed buildings including [name] which, along with the appeal property, make an important contribution to its historical and architectural significance.

The proposal is for the erection of a double dormer window, which would extend over around half the width and depth of the rear roof plane. The cheeks and face of the dormer would be finished in zinc cladding and the windows would be constructed from powder coated aluminium.

The external materials proposed would reflect the existing building and the contemporary design would reflect the simple built form of [site address] which incorporates a varied and visually interesting roof. The dormer is large; however, the substantial, interconnected roof planes can comfortably accommodate the proposed scheme. The host property would continue to read as an ancillary building within the wider garden setting. In light of these factors the proposed scheme would preserve the character and appearance of the MHCA.

The proposed dormer would not reflect the existing dormers on [name], which are smaller and more discrete. However, these buildings are distinctly different architecturally which warrants a different design approach in this instance.

The orientation of [site address] and the position of the dormer is such that it would not be clearly visible from [name]. The proposed external materials and design would ensure that [site address] would remain subservient, and [name] would retain its visual prominence within both short and longer range views within the surrounding gardens. As such the appeal proposal would preserve the setting of this listed building and the contribution the appeal property currently makes to its significance.

In conclusion I find that the proposed development would respect the character and appearance of the host property to the extent that it would preserve the character and appearance of the MHCA and the setting of the [name] listed building [name]. Hence, there would be no conflict with s72(1) and s66(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990, Policy D3 of the London Plan 2021, [name], CS1 and CS5 of Barnet’s Local Plan ([name]) Development Plan Document 2012 and Policies DM01 and DM06 of the DMP. When read together, these policies seek to ensure high quality design in development and where appropriate, conserve and enhance the distinctiveness of Barnet and to proactively protect and enhance Barnet’s heritage including conservation areas and listed buildings. There would also be respect for the Framework insofar as it relates to achieving well-designed places and conserving and enhancing the historic environment.

A letter of objection was submitted on behalf of the Conservation Area Advisory Committee raising concerns regarding the design of the dormer and the quality of the submitted Location Plan. The design of the proposed dormer is assessed within the reasons section above. The Council accepted the submitted Location Plan and as the site can be clearly identified I see no reason to disagree with the Council in this respect.

I have considered the conditions put forward by the Council and the appellant’s comments on them. They meet the tests set out at paragraph 56 of the Framework, and I have included them with some minor editing of the suggested wording for precision and enforceability.

I have attached conditions specifying the timescale for the initiation of the development and specifying the approved plans in the interests of certainty. A condition regarding proposed external materials has also been attached to protect the character and appearance of the MHCA.

For the reasons given above the appeal should be allowed.