Appeal 3314307

The appeal is dismissed.

A new version of the National Planning Policy Framework (the Framework) was published on 5 September 2023. The sections on Green Belt and heritage assets have not changed, so no injustice has been caused by the revised Framework.

The Council has raised no concern with use of the garage as a habitable room and on the evidence before me I see no reason to disagree. Therefore, the main issues are: i. whether the proposed extension would be inappropriate development in the Green Belt having regard to the Framework and any relevant development plan policies; ii. the effect of the proposal on the openness of the Green Belt; iii. whether the proposal would preserve or enhance the character and appearance of the Aldenham Conservation Area, and its effect on the significance of Nos 1 and 2 [address] Cottages as locally listed buildings; and iv. whether any harm by reason of inappropriateness, and any other harm, would be clearly outweighed by other considerations, so as to amount to the very special circumstances required to justify the proposal.

Paragraph 149 of the Framework states the construction of new buildings in the Green Belt is inappropriate subject to several exceptions. These include c) 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.

This approach is reflected in Policy CS13 of the Hertsmere Local Plan (HLP) [name] 2013 (CS). In addition, Policy SADM26 of the HLP Site Allocations and Development Management Policies Plan 2016 (SADMP) states that an extension or alteration to a building in the Green Belt must not individually or cumulatively be disproportionate in scale to the original building; and the addition must be subordinate to the original.

No 1 [address] Cottages has already been extended to the side under planning permission reference TP/08/0974. I understand that extension increased the size of the original building by 25 percent. The detached garage, granted permission under application reference TP/10/0933, added another 19 percent, approximately.

By linking the garage to the existing extension, the proposed development would add a further 12 percent to the size of the original dwelling. The parties agree this would result in a cumulative increase over and above the size of the original building of approximately 56 percent. I accept that on its own the proposed extension would be proportionate in scale and subordinate to the dwelling in its current form. However, given this cumulative increase, the proposal would result in disproportionate additions to the original building.

For this reason, I conclude the proposed extension would lead to inappropriate development in the Green Belt, contrary to paragraph 149 of the Framework, Policy CS13 of the CS and Policy SADM26 of the SADMP. Paragraphs 147 and 148 of the Framework state that inappropriate development is, by definition, harmful to the Green Belt and that substantial weight should be given to any such harm.

A fundamental aim of Green Belt policy, as set out in paragraph 137 of the Framework, is to keep land permanently open. Openness can be perceived spatially and visually. The openness of the appeal site lies in the space surrounding the semi-detached cottages and their extensions and outbuildings, which affords views from [address] of the woods behind and glimpses of the landscape beyond. From the start of the public footpath at the rear of the cottages, there are also glimpses of the space in front of them through the woods and between the garage and house on the appeal site.

By filling the gap between the existing extension and the separate garage, the proposal would increase the built footprint of the appeal premises, thereby reducing the spatial openness that surrounds it. The proposal would also detract from visual openness by limiting the views and glimpses currently visible through the gap from both directions, and by changing the appearance of the dwelling to a single unbroken mass. This would be notwithstanding that the new element would be contained within the built ‘envelope’ of the house.

I acknowledge there is an existing fence linking the garage to the house’s existing side extension. Nevertheless, this linking structure is clearly seen as a timber fence rather than part of the building, and it includes a gate that has potential to open to reveal the current gap. There is also no mass behind the fence, so the gap can be appreciated from the rear.

Although set back from the line of the fence and with a flat roof, the proposed link extension would be taller than both the fence and the eaves height of the garage. It would therefore appear larger than the current structure, and the symmetry with the fence on the other side of the garage would be lost. In addition, whilst the proposed use of timber facing materials would complement the appearance of the cottage and look similar to a fence, the windows and rooflight on the new extension would clearly identify it as part of the building.

Overall, I find there would be moderate harm to the openness of the Green Belt, to which, as set out in the Framework, I give substantial weight.

Aldenham Conservation Area (ACA) encompasses Aldenham village, comprising groups of mainly historic dwellings and their grounds arranged around the central parish church and village green. Several buildings and structures within the village are listed or locally listed. The ACA’s significance is historic in conserving the early layout and evolution of the village; and architectural as a collection of individually important historic buildings within their village setting.

Nos 1 and 2 [address] Cottages are a locally listed pair of semi-detached two-storey early 19th century workers’ cottages, set back facing [address]. Their significance as non-designated heritage assets derives from their symmetrical and simple design, characteristic of the period, and from features including the gable slate roof, central decorated chimney stack and window configuration. It also derives from their history as part of the old village of Aldenham. Nos 1 and 2 [address] Cottages therefore make a positive contribution to the significance of the ACA.

Paragraph 199 of the Framework requires great weight to be given to the conservation of a designated heritage asset when considering the impact of a proposed development on its significance. Paragraph 203 states that, in weighing applications that directly or indirectly affect non-designated heritage assets, a balanced judgement will be required having regard to the scale of any harm and the significance of the heritage asset.

By linking the garage to the main dwelling, the proposed extension would undermine the historic form of No 1 [address] Cottages to create a single built mass. Notwithstanding the set back position, subservient scale, flat roof and understated style of the proposed addition, the built form of No 1 would be different from that of No 2. This would be detrimental to the characteristic simple design and symmetry of the pair, and the difference would be visible from [address]. This harm would in turn detract from the character and appearance of the ACA, given the cottages’ positive contribution to the ACA’s historic and architectural significance. Siting of the extension within the curtilage of the existing building and use of sympathetic materials would not outweigh this harm.

For these reasons, I conclude there would be harm to the significance of Nos 1 and 2 [address] Cottages as non-designated heritage assets. I also conclude the proposal would neither preserve nor enhance the character or appearance of the ACA and would therefore harm its significance. I consider the harm to the ACA would be less than substantial.

Paragraph 202 of the Framework states that, where a development proposal will lead to less than substantial harm to the significance of a designated heritage asset, this harm should be weighed against the public benefits of the proposal. The proposal would make a modest contribution to economic growth during the construction process, to which I give limited weight. However, this public benefit would not outweigh the harm I find to the significance of the ACA. It would also not outweigh the harm to the locally listed buildings. Therefore, the proposal would conflict with the Framework.

I also conclude the proposal would conflict with Policies CS14 of the CS and Policy SADM29 of the SADMP. These policies seek to conserve and enhance the historic environment of the Borough; avoid the cumulative effect of smaller scale proposals on Conservation Areas; and maintain or improve the appearance and character of locally listed buildings.

I have given limited weight to the modest economic contribution of the proposal noted above.

The appellant states the extension would not provide additional accommodation, but the plans before me suggest the space would be used as a TV/playroom, in addition to providing an internal link between the garage and the main house. Be that as it may, I accept the proposal would provide a more convenient layout for occupants of the dwelling, enabling home working. I attribute limited weight to this benefit.

The Council has raised no concern with the effect of the proposal on parking or the living conditions of neighbouring occupiers. From the evidence before me I see no reason to disagree. I also accept there would be little change to the front and rear gardens, and little effect on trees or ecology. However, compliance with the development plan in these regards is a neutral factor.

I acknowledge the size of the proposed extension was reduced during consideration of the planning application in response to comments from the Council and its heritage advisor. Nevertheless, I have considered the proposal on its merits based on the evidence before me.

The appeal site is within the setting of three listed buildings. The Grade I listed Church of [name] the Baptist has 12th century origins with several later additions and alterations. Its significance lies primarily in its rectangular plan, west tower and many historic elements; and in its relationship as parish church with its setting in the surrounding churchyard and village of Aldenham. [name] listed [address] is the former vicarage with early 18th century origins. Its significance derives from its historic design elements to both front and rear and its setting includes its garden and the nearby church and churchyard. [name] listed [name] is a former 16th century house with 19th and 20th century alterations and additions. Its significance lies primarily in its partly exposed timber frame, structural features, and other elements including windows and materials. Its setting includes the church, churchyard, cricket pitch and houses along [address].

Given the modest scale of the proposed extension and limited inter-visibility between it and the listed buildings, on balance I consider there would be no material impact from the proposal on their significance or setting. The setting of the listed buildings would therefore be preserved.

According to paragraphs 147 and 148 of the Framework, inappropriate development in the Green Belt should not be approved except in very special circumstances. These will not exist unless the harm to the Green Belt, and any other harm resulting from the proposal, are clearly outweighed by other considerations.

I am required to give substantial weight to the harm the development would cause to the Green Belt by virtue of its inappropriateness and to openness. I also give great weight to the harm to the significance of the ACA and locally listed buildings as heritage assets. The weights I have attached to the other considerations, individually or cumulatively, do not clearly outweigh these harms. Consequently, the very special circumstances necessary to justify the development do not exist.

I have found the proposal conflicts with the development plan, read as a whole. No other material considerations, including the Framework, have been shown to indicate that a decision should be taken otherwise than in accordance with it. Therefore, the appeal is dismissed.