Appeal 3326747

The appeal is allowed and planning permission is granted for the erection of two storey side extension at [site address] , [site address] , [site address] , Hertfordshire [postcode] in accordance with the terms of the application Ref 23/00621/FHA, dated 9 March 2023, subject to the conditions appended to this

Since the appeal was lodged, a revised version of the National Planning Policy Framework (the Framework) was published (December 2023). This does not materially change the planning policy context in respect of the main issues.

The main issues are: • whether the proposed development would be inappropriate development in the Green Belt, having regard to the National Planning Policy Framework (the Framework) and any relevant development plan policies; • the effect of the proposed development on trees; and • if the development is inappropriate, whether the 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 proposed development.

The appeal site comprises a 2/2.5 storey dwelling positioned within a reasonably large plot. It is located on the private residential road of [site address] .

National Green Belt policy in the Framework sets out that inappropriate development is, by definition, harmful to the Green Belt and should not be approved ‘except in very special circumstances.’ There are, however, certain exceptions. One of those, at paragraph 154, is the extension or alteration of a building, provided it does not result in disproportionate additions over and above the size of the original building. Policy CS5 of the [name] 2006- 2031 (CS, 2013) broadly conforms to the general thrust of national Green Belt policy, which in summary supports the limited extension of existing buildings.

The Framework does not provide a definition of ‘disproportionate additions’ and therefore an assessment of whether a proposal would amount to a disproportionate addition over and above the size of the original building is a matter of planning judgement. The submitted evidence refers to Saved Policy 22 of the Dacorum Borough Local Plan (2004). It is understood that this set out a percentage increase ‘ceiling’ for an extension to be regarded as ‘limited in size’. However, I have not been provided with a copy of that policy, nor did it appear in the decision notice. Accordingly, it has had no part in my decision.

The term ‘original building’ is described in the Framework1 as ‘a building as it existed on 1 July 1948 or, if constructed after 1 July 1948, as it was built originally.’ No alternative Local Plan definition of original building is before me.

With this in mind, planning permission was granted in 2005 for the demolition of a former property on the same site, known as Kenslea. That permission also granted the construction of a replacement detached dwelling. That dwelling now exists on site, and was constructed after 1 July 1948. Within its submitted evidence, the Council takes the former dwelling, Kenslea, to be the original building and uses its floorspace as a baseline for calculating the addition of floorspace over time. However, given that this former dwelling was demolished in its entirety, and with no definition of ‘original building’ in the Local Plan that differs from the Framework, I consider the existing dwelling of [site address] , for the purposes of this particular case, to form the original building. In that regard, the total uplift in floorspace over time is significantly less than that calculated by the Council. Nevertheless, even were I to accept the Council’s baseline, a calculation of increased floorspace is not the only way in which to consider proportionality.

The proposed development would involve the erection of a two-storey extension to the north elevation of the existing dwelling. The proposal would increase both the footprint of the property and its volume. However, whether or not the above baseline is used, the scale of the extension, to my mind, would be limited in extent relative to [site address] . With respect to CS Policy CS5, it would have no significant impact on the character and appearance of the countryside and would have a neutral effect on the rural economy and maintenance of the wider countryside.

My attention is also drawn to an extant permission for a single-storey extension. The proposal would be of the same footprint as this, but also include a first floor element. This would be of a similar design to the main house. The increase relative to that extant extension (41sqm) would be, similarly, limited.

For the above reasons, I conclude that the proposed development would not be inappropriate development in the Green Belt. The proposed development would 1 Annex 2: Glossary therefore accord with the relevant provisions of CS Policy CS5, which in summary seeks to limit extensions to dwellings in the Green Belt. This is in a similar vein to the objectives of the Framework insofar as development in the Green Belt is concerned.

A number of semi-mature trees, along with hedging, exist along the north-west boundary of the site, near to the position of the proposed development. These trees are not readily visible or prominent from the public realm by reason of their position behind more mature landscaping and established built form. For these reasons, the visual amenity value of the trees is limited. CS Policy CS12 seeks to ensure that important trees are retained or replaced with suitable species if their loss is justified.

I note that no tree survey has been provided in support of the proposed development. However, it is not proposed to remove any trees as part of the proposed development and the site has been the subject of a recent planning decision for a single-storey extension2. The footprints of that scheme and the scheme before me are the same. The extension is also shown in the submitted evidence to be outside of any root protection areas.

I have no substantiated evidence before me to demonstrate that the trees in this location would be unlikely to survive on site for many years following the construction of the proposed development. However, the provision of protective measures during the course of works would be reasonable, and this could be adequately dealt with by condition.

Overall, I conclude that, subject to condition, the proposed development would be acceptable in respect of the amenity of trees, in accordance with the relevant provisions of [name] CS11 and CS12. These policies, in part, seek to ensure that important trees are retained. This is in a similar vein to the objectives of Saved Policy 99 of the Dacorum Borough Local Plan (2004).

In addition to the standard three-year time limit condition, I have imposed a condition requiring the development to be carried out in accordance with the approved plans. This is necessary for certainty. I have imposed a further condition relating to the protection of retained trees during construction in order to ensure their longevity.

As the proposal would not be inappropriate development in the Green Belt, and hence there would be no harm caused to it, it has not been necessary for me to take into account other identified considerations.

In light of the above reasoning, and having regard to all matters raised, I conclude that the appeal should be allowed.

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 (all starting 20 633): PL30; PL31; PL33.

The external surfaces of the development hereby permitted shall be constructed in the materials shown on plan PL33 and as specified on the application form.

All retained trees and hedges shown on plan PL31 and any trees whose canopies overhang the site shall be protected by strong fencing, the location and type to be first approved in writing by the Local Planning Authority. The fencing shall be erected in accordance with the approved details before any equipment, machinery or materials are brought onto the site for the purposes of the development, and shall be maintained until all equipment, machinery and surplus materials have been removed from the site. Nothing shall be stored or placed within any fenced area, and the ground levels within those areas shall not be altered, nor shall any excavation be made, without the prior written consent of the Local Planning Authority. In this condition “retained tree” means an existing tree which is to be retained in accordance with the approved plans and particulars.