Appeal 3332109

The appeal is allowed and planning permission is granted for two storey side extension at [site address] , [site address] , [name], Hertfordshire, [postcode] in accordance with the terms of the application, Ref. 5/23/0465, dated 2 March 2023, subject to the following conditions:

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

The development hereby permitted shall be carried out in accordance with the following approved plans: S1606/10 OS Plan; B1606/13/A Block Plan; P1606/12/[name]; and P1606/11/A Proposed Floor Plans.

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 description of the development in the banner heading has been taken from the planning application form. However, in the formal decision I have omitted reference to the application being a resubmission to reflect the definition of development within the terms of the Planning Acts.

Since the appeal was lodged a revised version of the National Planning Policy Framework (the Framework) has been published. However, as the policies of relevance to this proposal have not changed fundamentally it has not been necessary to seek comments from the parties. I have referred to the current paragraph numbers of the Framework in this decision.

The main issues are: • whether the proposal is inappropriate development within the Green Belt (GB) for the purposes of planning policy set out in the Framework and the development plan; • the effect on the openness of the GB; and • if the development is inappropriate, whether the harm by reason of inappropriateness, and any other harm, is clearly outweighed by other considerations so as to amount to the very special circumstances necessary to justify the development.

The appeal property is a semi-detached house located at the edge of what appears as a suburban residential area within the Green Belt. The site is prominently located next to an open green space, but is otherwise seen as part of this established housing group.

The Framework confirms that the construction of new buildings should be regarded as inappropriate in the GB, with some exceptions. One of these is the extension or alteration of a building, provided that it does not result in disproportionate additions over and above the size of the original building. Although the Framework does not define “disproportionate” by reference to any size criteria, in support of Policy 13 of the City and District of St Albans District Local Plan Review 1994 (LP), the Council applies its Supplementary Planning Guidance, ‘[name] and [name] in the Green Belt’ 2004 (SPG).

This document and the Council’s policies pre-date by some margin the current Framework, and their wording is not wholly consistent with the national approach; rather than “disproportionate”, LP Policy 13 applies the term “significantly larger or different in character”, and relates to extensions to houses rather than buildings. This reduces the weight to be afforded the policy and guidance. In any event, the SPG confirms that its figures are guidelines rather than rigid limits, conferring a degree of flexibility in their application.

In essence, the SPG seeks to limit the size of side and rear extensions in the GB to an increase of between 90m3 and 180m3, and a percentage increase in floorspace of 20% to 40%. However, the SPG also sets out site-specific criteria used to determine whether or not an acceptable extension should be towards the top or bottom of these size ranges. This includes the visibility of the proposal.

There is dispute between the parties about the degree of change that would result. The Council considers the increase would be approximately 57.73% in floorspace, and towards the upper end of the ‘acceptable’ volume range. The appellant considers that, even taking into account an existing porch, the floorspace increase would equate to 51%, and again, the volume would be within range. An outbuilding some 9m from the dwelling would further add to the floorspace, if included in calculations, but Table 3 of the SPG suggests that only garages within 5m of the original dwelling will be classed as an extension.

Whilst a numerical analysis is a useful starting point, it is evident that the Council applies these guidelines flexibly, as shown in the nearby planning permissions cited by the appellant. [name] note the Council’s assessment that the site contexts are not comparable, viewed on the ground I did not find the differences to be so marked. This demonstrates the value of considering the visual impact of the proposal alongside a mathematical calculation.

In this case, the site is prominent at the edge of the housing group and next to an open space, but is also seen in the context of other extended dwellings which overlook this open space. The existing side projection and covered parking at the appeal site create a somewhat cluttered appearance to the side of the dwelling, and do not particularly contribute to any sense of space. As part of the established housing group, the appeal property is distinct from the expanse of open green space outside of the appeal site.

Whilst taking into account the existing front extension, the width and depth of the proposal would appear subordinate to the host dwelling, and would be consistent with the scale and proportions of other extensions in the vicinity. It would replace an existing single-storey side projection, which the Council considers to be non-original. Nevertheless, it would be removed, as would a temporary garage-style structure. Although this is clearly not part of the original building, or an extension, it occupies space close to the dwelling. The scale and visual impact of the proposal would not create a building significantly larger or different in character than the original dwelling, in accordance with LP Policy 13.

This is consistent with the Council’s assessment of the design merits of the proposal: the delegated report confirms that the proposal would be in keeping with the existing dwelling, and although large, would not be dominant, and would be sympathetic to the street scene. The report confirms that the proposal would accord with [name] 69 and 72.

I therefore conclude that the proposal would not result in a disproportionate addition over and above the size of the original building, and in so doing would not be inappropriate development in the GB. It would not conflict with the Framework and the aims of [name] 1 and 13 and the SPG. Although cited in the reason for refusal, given the Council’s analysis I find no conflict with the design requirements set out in [name] 69 and 72.

Impact on openness is implicitly taken into account in the exception to inappropriate development specified at paragraph 154 c) of the Framework. Having found the proposal to be not inappropriate, no further assessment is required on this point, and no very special circumstances need to be demonstrated to justify the development.

In addition to the standard time limit, I have attached a condition specifying the approved drawings as this provides certainty. It is also appropriate to control materials to match the existing dwelling, in order to safeguard the character and appearance of the development and the area.

For the reasons given above I conclude that the appeal should be allowed.